Extracellular polymeric substances

In this study, the refinery wastewater produced by the integrated gasification combined cycle (IGCC) and pre-treated in a lab-scale partial nitritation chemostat was fed to a granular anammox reactor, in order to evaluate its feasibility as the final treatment step. The IGCC wastewater was characterized by high NH 4 -N concentration (540±82 mg L -1 ), high organic carbon to nitrogen ratio (C org /N), and by the presence of toxic substances. A conservative exponential law was adopted to progressively replace the synthetic influent with the pre-treated IGCC wastewater, in order to avoid any stressful conditions which could hinder the process. An increase in specific anammox activity (SAA) up to 0.104 gNO 2 -N gVSS -1 d -1 was initially observed, suggesting that stimulation may occur if pre-treated IGCC wastewater dilution is sufficiently high. A system malfunction caused a worsening of process performance, which was partially restored: when only pre-treated IGCC wastewater was fed, the nitrogen removal efficiency and SAA were 71±3% and 0.045±0.002 gNO 2 -N gVSS -1 d -1 , respectively, and the removal of organic matter due to denitrification was negligible. As to physical/morphological properties of anammox granules, they did not change significantly during the whole experimental campaign. Results showed that the anammox process can be successfully applied to treat complex industrial wastewaters with high C org /N ratio, if a conservative start-up strategy is adopted and the preliminary partial nitritation step guarantees an efficient removal of readily degradable organic matter.

Nitrogen pollution has been serious problem in environmental water particularly in freshwater ecosystems. A heterotrophic nitrifier and aerobic denitrifier was isolated and characterised from domestic wastewater. Based on phenotypic and phylogenetic characteristics, the isolate was identified as Klebsiella pneumonia. The strain had the capability to utilise ammonia, nitrate and nitrite as a sole nitrogen source. The maximum growth rate (m max ) of isolate was 0.55 h À1 when ammonia used as nitrogen source. The isolate could express hydroxylamine oxidase (hao), periplasmic nitrate reductase (nap) and nitrite reductase (nir) which are essential for heterotrophic nitrification and aerobic denitrification. Both hao and napA genes were amplified in isolated strain by PCR. Furthermore, the isolate showed capacities of extracellular polymeric substances (EPS) secretion and auto-aggregation. Results demonstrated that the isolation of heterotrophic nitrifier and aerobic denitrifier favoured the bioremediation of nitrogenous compounds from domestic wastewater.

Microbes (bacteria, phytoplankton) in the ocean are responsible for the copious production of exopolymeric substances (EPS) that include transparent exopolymeric particles. These materials act as a matrix to form marine snow. After the Deepwater Horizon oil spill, marine oil snow (MOS) formed in massive quantities and influenced the fate and transport of oil in the ocean. The processes and pathways of MOS formation require further elucidation to be better understood, in particular we need to better understand how dispersants affect aggregation and degradation of oil. Toward that end, recent work has characterized EPS as a function of microbial community and environmental conditions. We present a conceptual model that incorporates recent findings in our understanding of the driving forces of MOS sedimentation and flocculent accumulation (MOSSFA) including factors that influence the scavenging of oil into MOS and the routes that promote decomposition of the oil post MOS formation. In ...

Using the atomic force microscope, we have investigated the nanoscale mechanical response of the attachment adhesive of the terrestrial alga Prasiola linearis (Prasiolales, Chlorophyta). We were able to locate and extend highly ordered mechanical structures directly from the natural adhesive matrix of the living plant. The in vivo mechanical response of the structured biopolymer often displayed the repetitive sawtooth force-extension characteristics of a material exhibiting high mechanical strength at the molecular level. Mechanical and histological evidence leads us to propose a mechanism for mechanical strength in our sample based on amyloid fibrils. These proteinaceous, pleated β-sheet complexes are usually associated with neurodegenerative diseases. However, we now conclude that the amyloid protein quaternary structures detected in our material should be considered as a possible generic mechanism for mechanical strength in natural adhesives.

An unprecedented period of phosphogenesis, along with massive deposition of black shales, major perturbations in the global carbon cycle and the rise of atmospheric oxygen, occurred in the terminal Proterozoic in the aftermath of the Marinoan glaciation. Although causal links between these processes have been postulated, evidence remains challenging. Correlated in situ micro-analyses of granular phosphorites from the Ediacaran Doushantuo Formation in Yichang, South China, suggested that cyanobacteria and associated extracellular polymeric substances (EPS) might have promoted aggregated granule growth and subsequent phosphatization . Here, we present new paleontological data for the Doushantuo phosphorites from Yichang, which, combined with Raman microspectroscopy and carbon isotope data, further document links between the biology of cyanobacteria and phosphogenesis. Mapping of microfossils in thin section shows that most phosphatic granules contain microfossils that are dominated by colonies of Myxococcoides, along with several filamentous genera generally considered to represent cyanobacterial sheaths. In addition, the phosphorites and associated rocks have ␦ 13 C org values in the range of -26.0 to -29.7‰ VPDB, consistent with photoautotrophic carbon fixation with the Rubisco enzyme. Close association of phosphorites with the Marinoan tillites in stratigraphic level supports a genetic link between deglaciation and phosphogenesis, at least for the Doushantuo occurrence. Our new data suggest that major cyanobacterial blooms probably took place in the terminal Proterozoic, which might have resulted in rapid scavenging of bioavailable phosphorus and massive accumulations of organic matter (OM). Within a redox-stratified intra-shelf basin, the OM-bound phosphorus could have liberated by microbial sulfate reduction and other anaerobic metabolisms and subsequently concentrated by Fe-redox pumping below the chemocline. Upwelling of the bottom waters or upward fluctuation of the chemocline might have brought P-enriched waters to the photic zone, where it was again scavenged by cyanobacteria through their EPS to be subsequently precipitated as francolite. The feedbacks between enhanced continental weathering, cyanobacterial blooms, carbon burial, and accelerated phosphorus cycle thus controlled the marine biogeochemical changes, which led to further oxygenation of the atmosphere and oceans, ultimately paving the way for the rise of metazoans.

We report the soil microbial diversity and functional aspects related to degradation of recalcitrant compounds, determined using a metagenomic approach, in a landfill lysimeter prepared with soil from Ghazipur landfill site, New Delhi, India. Metagenomic analysis revealed the presence and functional diversity of complex microbial communities responsible for waste degradation. S oil provides an intricate and challenging environment for microbiologists, with a large percentage of uncharacterized microbes that can be elucidated only through a metagenomic approach (1, 2). A lysimeter is a simulation of existing landfill conditions for waste degradation and leachate treatment that helps to resolve the problems associated with unengineered waste dumping sites (3). The aim of this study was to investigate through a metagenomic approach the functional genetic diversity of the diverse microbial communities responsible for degradation in a landfill lysimeter. Samples were collected in August 2016 from a landfill site (28°37=25.11ЉN, 77°19=36.1ЉE) located at the Ghazipur area in New Delhi, India. A composite sample was prepared from sampling positions and transferred to the physical setup of a lysimeter to study the leachate characteristics in an open dump. DNA was extracted from a landfill lysimeter soil sample using an Exgene soil DNA kit (GeneAll Biotechnology Co., Ltd.). Paired-end sequencing libraries (2 ϫ 150 bp) were prepared using an Illumina TruSeq Nano DNA library pep kit followed by sequencing using the Illumina NextSeq 500 platform. The raw reads were processed through Trimmomatic v 0.35 (4) to obtain high-quality clean reads devoid of adapter sequences and low-quality reads. The high-quality reads were assembled through CLC Genomics Workbench. Prodigal 2.6.3 (5) was used with default parameters to predict genes from the assembled scaffolds. Kaiju (6) (a program for sensitive taxonomic classification of high-throughput metagenomic sequencing data) was used for taxonomical analysis of the predicted genes, and functional analysis of genes from the sample was carried out using COGNIZER (7) (a comprehensive standalone framework) enabled to simultaneously provide COG (8), KEGG (9), Pfam (10), GO (11), and SEED (12) subsystems annotation to individual sequences constituting metagenomic data sets. A mean library fragment size of 490 bp and ϳ3 Gb high-quality data were obtained. A total of 10,254,512 high-quality reads were assembled into scaffolds. A scaffold of 406,004 bp was retrieved, with an N 50 value of 454 bp. The software predicted a total of 258,260 genes with an average length of 337 bp. The predicted genes with Ͻ300 bp were excluded from taxonomical analysis and functional classification. Taxonomical classification was performed, and the results consisted of 65.80% bacteria, 2.93% Archaea, 0.92% eukaryotes, 0.13% viruses, and 30.23% unclassified organisms. The phylum Proteobacteria, with a percentage abundance of 28.24%, was found to be the most dominant phylum. The other major phyla and percentage abundances were

Although the production of extracellular polymeric substances (EPS) has long been recognized as an important factor in bacterial adhesion processes, little is known about the supramolecular organization of EPS adsorbed on solid surfaces. In this paper, atomic force microscopy (AFM) is used to probe, under aqueous conditions, the nanoscale morphology and molecular interactions of polystyrene substrata after adhesion of the Gram-negative bacterium Azospirillum brasilense under different experimental conditions. After cell adhesion under favourable conditions (24 h contact time at 30 °C), topographic images revealed that the substratum surface was covered by a continuous layer of adsorbed substances, :2 nm thick, from which supramolecular aggregates were protruding. These adsorbed substances, attributed to proteinaceous EPS, were found to cause a significant change of substratum solvation properties: adhesion force mapping performed over 5 ×5 mm areas with a silicon nitride probe showed adhesion forces of 0.8 9 0.2 nN (n= 1024) magnitude on bare substrata, while forces of only 0.2 90.2 nN magnitude were found after cell adhesion. Finally, when the cell adhesion test was performed under unfavourable conditions (2 h at 30 °C or 24 h at 4 °C), there was no/little indication of the presence of an adsorbed layer and of a change of substratum solvation properties. The correlation between the AFM data and the cell adhesion behaviour provides evidence for the involvement of proteinaceous EPS in the adhesion of A. brasilense to solid surfaces.

Activated sludge models Kinetic parameters Influent fractionation Soluble microbial products (SMP) Exo polymeric substances (EPS) a b s t r a c t Membrane bioreactors (MBRs) have been increasingly employed for municipal and industrial wastewater treatment in the last decade. The efforts for modelling of such wastewater treatment systems have always targeted either the biological processes (treatment quality target) as well as the various aspects of engineering (cost effective design and operation). The development of Activated Sludge Models (ASM) was an important evolution in the modelling of Conventional Activated Sludge (CAS) processes and their use is now very well established. However, although they were initially developed to describe CAS processes, they have simply been transferred and applied to MBR processes. Recent studies on MBR biological processes have reported several crucial specificities: medium to very high sludge retention times, high mixed liquor concentration, accumulation of soluble microbial products (SMP) rejected by the membrane filtration step, and high aeration rates for scouring purposes. These aspects raise the question as to what extent the ASM framework is applicable to MBR processes. Several studies highlighting some of the aforementioned issues are scattered through the literature. Hence, through a concise and structured overview of the past developments and current state-of-the-art in biological modelling of MBR, this review explores ASMebased modelling applied to MBR processes. The work aims to synthesize previous studies and differentiates between unmodified and modified applications of ASM to MBR. Particular emphasis is placed on influent fractionation, biokinetics, and soluble microbial products (SMPs)/exo-polymeric substances (EPS) modelling,

In this study, a coupled system of algal-sludge and membrane bioreactor (AS-MBR) was established for fouling control, and meanwhile the performance of wastewater treatment was enhanced. Results indicated that the AS-MBR increased the COD, NH 4 þ-N, TN and PO 4 3-P removal efficiencies from 91.7% to 95.9%, 90.8%e96.9%, 22.0% to 34.3% and 18.4%e32.6%, respectively. Further analysis suggested that in the AS-MBR, the total specific oxygen utilization rate (SOUR), the SOUR of ammonia oxidizing bacteria and the SOUR of nitrite oxidizing bacteria were 26.6%, 58.5% and 52.4% higher than the control, respectively, indicating the improvement of microbial activities in AS-MBR. Additionally, the membrane fouling rates in the AS-MBR were 52.6% and 32.2% lower than the control in the slow and rapid fouling processes, respectively. A further mechanism investigation demonstrated that the concentrations of extracellular polymeric substance (EPS) were decreased by 19.8% and 22.1% in the mixed liquid and the fouling layer, respectively, after the inoculation of algae, which was expected to have a positive effect on the higher permeability and longer operation cycle of the membrane in the AS-MBR. More regular floc morphology was observed for the fouling layer on the membrane of AS-MBR, with the polysaccharides and proteins forming large clusters and channels in the fouling layer that likely decreased the filtration resistance. Consequently, high-throughput sequencing analysis revealed that the microbial community in the AS-MBR had higher abundances of bacteria and algae related to nutrients and organic matters degradation, which was beneficial for the improvement of wastewater treatment and alleviation of membrane fouling.

Extracellular polymeric substances (EPS) produced by microorganisms are a complex mixture of biopolymers primarily consisting of polysaccharides, as well as proteins, nucleic acids, lipids and humic substances. EPS make up the intercellular space of microbial aggregates and form the structure and architecture of the biofilm matrix. The key functions of EPS comprise the mediation of the initial attachment of cells to different substrata and protection against environmental stress and dehydration. The aim of this review is to present a summary of the current status of the research into the role of EPS in bacterial attachment followed by biofilm formation. The latter has a profound impact on an array of biomedical, biotechnology and industrial fields including pharmaceutical and surgical applications, food engineering, bioremediation and biohydrometallurgy. The diverse structural variations of EPS produced by bacteria of different taxonomic lineages, together with examples of biotechnological applications, are discussed. Finally, a range of novel techniques that can be used in studies involving biofilm-specific polysaccharides is discussed.

A bench-scale self-forming dynamic membrane bioreactor (SFD MBR) treating canning wastewater showed instable filtration performance, with a worsening in correspondence of a change in the influent quality. To unveil the possible reasons for such behaviour, a microbial investigation was carried out to complement conventional filterability and settleability tests. The microbial communities of the influent wastewater, the activated sludge, and the filtering sludge cake (dynamic membrane) were characterised through metagenomic and differential abundance analyses. In parallel, the production of exopolymers was measured. The outputs indicate that under the tested conditions the canning wastewater promoted the development of a very peculiar microbial ecosystem, with a strong selection of the genus Thiothrix (relative abundance above 90 %). The Shannon index values in activated sludge were below 2, indicating a very low bacterial diversity. This may have limited the ecosystem resilience towards changes of external conditions, causing instability in the process of the dynamic membrane formation. Furthermore, the diversity analysis showed that the bacterial compositions of the feed and the sludge resulted not significantly linked to each other, confirming the main role of the chemical composition of the influent wastewater on overall process performances. When treating agro-industrial streams, in-depth feed characterisation is recommended in order to prevent the factors that may generate instability in SFD MBR performance.

Nostoc calcicola produced profuse amount of polysaccharidic exopolymer under P limited conditions. The exopolymer showed a truly pseudoplastic, non-Newtonian, time independent behaviour with good recovery after shear. It was composed of D-ribose, D-arabinose, L-rhamnose, L-fucose, D-xylose, D-mannose, D-glucose, D-galactose and 3-methyl-D-arabinose. IR spectra showed bands at ~1250 and 820 cm, characteristic of sulphate residue. The exopolymer showed good emulsifying and antimicrobial activity. It absorbed 282 g H2O.g -1 exopolymer. The possible applications of the exopolymer in pharmaceutical, food and oil recovery industry have been discussed.

Biofilm formation and evolution are key factors to consider to better understand the kinetics of arsenopyrite biooxidation. Chemical and surface analyses were carried out using Raman spectroscopy, scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), glow discharge spectroscopy (GDS), and protein analysis (i.e., quantification) in order to evaluate the formation of intermediate secondary compounds and any significant changes arising in the biofilm structure of Acidithiobacillus thiooxidans during a 120-h period of biooxidation. Results show that the biofilm first evolves from a low cell density structure (1 to 12 h) into a formation of microcolonies (24 to 120 h) and then finally becomes enclosed by a secondary compound matrix that includes pyrite (FeS 2)-like, S n 2− /S 0 , and As 2 S 3 compounds, as shown by Raman and SEM-EDS. GDS analyses (concentration-depth profiles, i.e., 12 h) indicate significant differences for depth speciation between abiotic control and biooxidized surfaces, thus providing a quantitative assessment of surface-bulk changes across samples (i.e. reactivity and /or structure-activity relationship). Respectively, quantitative protein analyses and CLSM analyses suggest variations in the type of extracellular protein expressed and changes in the biofilm structure from hydrophilic (i.e., exopolysaccharides) to hydrophobic (i.e., lipids) due to arsenopyrite and cell interactions during the 120-h period of biooxidation. We suggest feasible environmental and industrial implications for arsenopyrite biooxidation based on the findings of this study.

Many cyanobacteria produce extracellular polymeric substances (EPS) mainly composed of heteropolysaccharides with unique characteristics that make them suitable for biotechnological applications. However, manipulation/optimization of EPS biosynthesis/characteristics is hindered by a poor understanding of the production pathways and the differences between bacterial species. In this work, genes putatively related to different pathways of cyanobacterial EPS polymerization, assembly, and export were targeted for deletion or truncation in the unicellular Synechocystis sp. PCC 6803. No evident phenotypic changes were observed for some mutants in genes occurring in multiple copies in Synechocystis genome, namely ∆wzy (∆sll0737), ∆wzx (∆sll5049), ∆kpsM (∆slr2107), and ∆kpsM∆wzy (∆slr2107∆sll0737), strongly suggesting functional redundancy. In contrast, Δwzc (Δsll0923) and Δwzb (Δslr0328) influenced both the amount and composition of the EPS, establishing that Wzc participates in the produc...

Cyanobacterial extracellular polymeric substances (EPS) are mainly composed of high-molecular-mass heteropolysaccharides, with variable composition and roles according to the microorganism and the environmental conditions. The number of constituents-both saccharidic and nonsaccharidic-and the complexity of structures give rise to speculations on how intricate their biosynthetic pathways could be, and how many genes may be involved in their production. However, little is known regarding the cyanobacterial EPS biosynthetic pathways and regulating factors. This review organizes available information on cyanobacterial EPS, including their composition, function and factors affecting their synthesis, and from the in silico analysis of available cyanobacterial genome sequences, proposes a putative mechanism for their biosynthesis.

Different effects of multi-walled carbon nanotubes (MWCNTs) on the freshwater diatom Nitzschia palea were examined. MWCNTs used in this study (MWCNT) were dispersed either by sonication without (MWCNT sonicated) or with a realistic concentration (10 mg L À1) of Natural Organic Matter (MWCNT +NOM). A pocket-size device was designed to distinguish shading effect (using MWCNT suspensions as external filters) from total exposure effect of MWCNT sonicated and MWCNT +NOM on benthic algae. This study demonstrates that cell division was strongly inhibited after a 48 h exposure to MWCNT +NOM compared to MWCNT sonicated. This device did not yield a quantifiable contribution of shading to growth inhibition of MWCNT sonicated and below 10 mg L À1 of MWCNT +NOM. In all cases, neither lethal effects nor drops in photosynthetic quantum yield were observed. After a 6-d exposure, a complete growth recovery was observed for all conditions except at the highest concentration of MWCNT +NOM. Different microscopic approaches using carbohydrates markers revealed the strong affinity between MWCNT and extracellular polymeric substances (EPS) produced by N. palea. These seem to constitute a defensive mechanism against MWCNT.

ASSESSING ENERGY REGIME EFFECTS ON PATHOGEN-PARTICLE INTERACTIONS LINKING WATER QUALITY TO ECOSYSTEMS AND PUBLIC HEALTH Sandra M. Tirado. Advisors: University of Guelph , 2012 Dr. S.N. Liss Dr. I.G. Droppo Dr. S.M. Glasauer Dr. M. Habash Floc-pathogen interactions are important determinants of the fate of pathogens in aquatic systems. The dissociation of bacteria from particles due to shear stress can significantly increase the presence of free-floating pathogenic bacteria in the aqueous phase. This has implications for pathogen transport and water quality. This study evaluated the interactions of water-borne pathogens with particles in selected aquatic ecosystems. Three experimental chapters and one concluding chapter is presented. Chapter 3 assesses the strength of the floc-microorganism association under different energy levels in relation to the physico-chemical properties and the bioorganic content of flocs from six different aquatic environments (SB, CSO, RF, AG, ML, MN); Chap...

h i g h l i g h t s Suitability of MBR for dye wastewater treatment is reviewed. MBR is suitable for end-of-pipe treatment compared to other processes. MBR combined with MF, UF, NF, MD can assist to recover dyes and reuse treated water. When RO is added to MBR, salts can be recovered. When FO/RO system is added to MBR, brine discharge from RO can be minimised.

Compared to the Conventional Activated Sludge Process (ASP), Membrane Bioreactors (MBRs) have proven their superior performance in wastewater treatment and reuse during the past two decades. Further, MBRs have wide array of applications such as the removal of nutrients, toxic and persistent organic pollutants (POPs), which are impossible or difficult to remove using ASP. However, fouling of membrane is one of the main drawbacks to the widespread application of MBR technology and Extra-cellular Polymeric Substances (EPS) secreted by microbes are considered as one of the major foulants, which will reduce the flux (L/m 2 /h) through the membrane. Critical flux is defined as the flux above which membrane cake or gel layer formation due to deposition of EPS and other colloids on the membrane surface occurs. Thus, one of the operating strategies to control the fouling of MBRs is to operate those systems below the critical flux (at Sub-Critical flux). This paper discusses the critical flux results, which were obtained from short-term common flux step method, for a lab-scale MBR system treating Ametryn. This study compares the critical flux values that were obtained by operating the MBR system (consisting of a submerged Hollow-Fibre membrane with pore size of 0.4µm and effective area of 0.2m 2) at different operating conditions and mixed liquor properties. This study revealed that the critical flux values found after the introduction of Ametryn were significantly lower than those of obtained before adding Ametryn to the synthetic wastewater. It was also revealed that the production of carbohydrates (in SMP) is greater than proteins, subsequent to the introduction of Ametryn and this may have influenced the membrane to foul more. It was also observed that a significant removal (40-60%) of Ametryn from this MBR during the critical flux determination experiments with 40 minutes flux-step duration.

The work reviewed here was published during 2009 and describes research that involves biofilms treating pollutants. The review is divided into the following sections: biofilm measurement and characterization, biofilm reactors, microbial fuel cells and biofilm models.

Hybrid processes coupling the use of powder activated carbon (PAC) with membrane filtration for drinking water production are emerging as promising alternatives to conventional technologies due to their enhanced control of dissolved contaminants. The quantification of biomass colonizing PAC is crucial for modeling, designing control strategies and improving the overall performance of these processes. The aim of this study was to examine the applicability of several common methods developed for colonized granular activated carbon (GAC) to PAC. Six analytical methods (based on the measurement of proteins, polysaccharides, heterotrophic plate counts, potential glucose respiration, bacterial ATP and a potential acetate uptake rate, which is proposed herein) were compared. The results showed that the rates of glucose respiration and of acetate consumption could be used interchangeably. Proteins were also an interesting alternative for on-site measurements. It was concluded that biological PAC-based processes sustained a level of heterotrophic activity similar to or greater than that observed in GAC biofilters.

While phytoplankton has been shown to influence climate in diverse ways, this review treats just two aspects: reduction of sea-air fluxes, and increase in ocean foam coverage. Plankton and neuston algae produce dissolved organic matter (DOM), which tends to concentrate in the seasurface microlayer (SML). Fluxes of matter and energy exchange across the sea-air surface and are important in regulating weather and climate. Freshly produced DOM shows marked surface and rheological activity, and it reduces these fluxes. Foam covers part of the ocean surface, largely produced by breaking and spilling waves. Its longevity is increased in areas subject to high biological productivity, and particularly during blooms of some species of harmful algae and may involve specific DOM molecules and the algal genes that produce them. Ocean foam is generally white and reflects about 50% of incident solar radiation, while the foam-free ocean surface reflects only about 5%. Thus, algal DOM helps to cool the planet by increasing foam coverage. Unpredictable changes in abundance and taxonomic composition of phytoplankton and phytoneuston may be adding uncertainty to modelling global and local climate. Further research on the roles of the ocean in climate regulation should thus pay more attention to algal communities, their specific genes and the physical and chemical characteristics of the DOM they produce.

Meat processing industries generate a great amount of wastewater. Because of the remote locations of companies in Northern Finland, they face the problem of low efficiency of traditional biological wastewater purification and the need for a decentralized energy supply system. Membrane separation processes integrated in wastewater purification technology could provide an eco-friendly, and economical solution for the small and medium sized meat processing enterprises (SME’s). The main aim of our research project was to find technology for the treatment of food industry wastewater, which is suitable for producing recyclable process water, and on the other hand, could provide an economical pre-concentration stage before anaerobic digestion (AD).

Domination of certain aerophytic phototrophic group or specific taxon in biofilms is connected with biofilm features recognised in situ. Well-developed, gelatinous, olive to dark-green biofilms are composed mostly of coccoid cyanobacterial forms. The same features, characterised biofilms dominated by one coccoid taxon, except the latter were vividly coloured. Gloeobacter caused the appearance of purple, Gloeocapsa representatives yellow and Chroococcidiopsis black biofilm. The brown to the dark colour of heterocytous biofilms was mainly caused by Nostoc. Simple trichal Cyanobacteria were occasionally present in biofilm, except in one bluecoloured sample. According to the principal component analysis (PCA), well-developed and gelatinous biofilms were correlated with Cyanobacteria, while scanning electron microscopy (SEM) revealed richness of extracellular polymeric substances (EPS) in such biofilms. Biofilm with calcified cyanobacterium (Geitleria cf. calcarea) was also found. Chlorophyta-abundant biofilms (many rich in Desmococcus), thinner than cyanobacterial, were predominantly green and occasionally yellow and blue. Many were dry when observed in situ (confirmed with PCA), with few being moistened (i.e. Klebsormidium-dominant). Diatom biofilms were usually developed on sediment, mosses or near seeping water (demonstrated by PCA) and were also thinner than cyanobacterial ones. Compared to cyanobacterial biofilms, SEM showed less developed EPS in those rich in diatoms and green algae, where microorganisms are more exposed to the environment. The study demonstrates an easy method for biofilm assessment based on visual characterisation and provides encouragement for more frequent biofilm investigation in caves that can be important from an ecological, biological, biotechnological point of view and which assessment can have an irreplaceable role in potential monitoring and protection.

Domination of certain aerophytic phototrophic group or specific taxon in biofilms is connected with biofilm features recognised in situ. Well-developed, gelatinous, olive to dark-green biofilms are composed mostly of coccoid cyanobacterial forms. The same features, characterised biofilms dominated by one coccoid taxon, except the latter were vividly coloured. Gloeobacter caused the appearance of purple, Gloeocapsa representatives yellow and Chroococcidiopsis black biofilm. The brown to the dark colour of heterocytous biofilms was mainly caused by Nostoc. Simple trichal Cyanobacteria were occasionally present in biofilm, except in one bluecoloured sample. According to the principal component analysis (PCA), well-developed and gelatinous biofilms were correlated with Cyanobacteria, while scanning electron microscopy (SEM) revealed richness of extracellular polymeric substances (EPS) in such biofilms. Biofilm with calcified cyanobacterium (Geitleria cf. calcarea) was also found. Chlorophyta-abundant biofilms (many rich in Desmococcus), thinner than cyanobacterial, were predominantly green and occasionally yellow and blue. Many were dry when observed in situ (confirmed with PCA), with few being moistened (i.e. Klebsormidium-dominant). Diatom biofilms were usually developed on sediment, mosses or near seeping water (demonstrated by PCA) and were also thinner than cyanobacterial ones. Compared to cyanobacterial biofilms, SEM showed less developed EPS in those rich in diatoms and green algae, where microorganisms are more exposed to the environment. The study demonstrates an easy method for biofilm assessment based on visual characterisation and provides encouragement for more frequent biofilm investigation in caves that can be important from an ecological, biological, biotechnological point of view and which assessment can have an irreplaceable role in potential monitoring and protection.

Research on biofilms has developed into interdisciplinary work, in which scientists from different fields are involved. This review summarizes the stateof-the-art including models due to different aspects of biofilms. Techniques for characterization of surfaces and interfaces, e.g. microscopic, spectroscopic and microsensoric methods will be presented. In addition, procedures that involve sampling of biofilms and subsequent separation of the components for their analysis are a part of this article. Analytical methods are summarized for the investigation of extracellular polymeric substances (EPS), mainly polysaccharides beside proteins in the microbial host. Finally, procedures for the analysis of minerals as components of biofilms are presented.

We report the application of confocal laser scanning microscopy CLSM and Raman spectroscopy on the (bio)chemical oxidation of pyrite and chalcopyrite, in order to understand how surface sulfur species () affects biofilm evolution during mineral colonization by Acidithiobacillus thiooxidans. We found that cells attachment occurs as cells clusters and monolayered biofilms within the first 12 h. Longer times resulted in the formation of micro- and macrocolonies with variable cell density and higher epifluorescence signal of the extracellular polymeric substances (EPS), indicating double dynamic activity of A. thiooxidans: sulfur biooxidation and biofilm formation. Raman spectra indicated consumption modification during biofilm evolution. Hence, cell density increase was primarily associated with the presence of ; the presence of refractory sulfur species on the mineral surfaces does not to affect biofilm evolution. The EPS of the biofilms was mainly composed of extracellular hydrophobi...

Background: Cells in general secrete nanoparticles (NPs) which are believed to mediate intercellular communication. Recently, great efforts have been made to utilize them as delivery vectors. We aimed to harvest and identify NPs from liquid cultures of two marine microalgae Dunaliella tertiolecta and Phaeodactyum tricornutum. Methods: NPs were isolated from the culture conditioned media by differential ultracentrifugation by the protocol used for the isolation of extracellular vesicles. Microalgae and isolated NPs were examined by scanning electron microscopy (SEM) while isolated NPs were examined also by cryogenic transmission electron microscopy (cryo-TEM). The Triton X-100 detergent and temperature sensitivity of NPs was assessed by dynamic light scattering (DLS) through monitoring the intensity of the scattered light (I) and the distribution of hydrodynamic radii of NPs (Rh). Results: Two mechanisms of formation of NPs with average Rh 200 nm were observed in the D. tertiolecta c...

Background Cyanobacteria are common components of phytoplankton communities in most freshwater ecosystems. Proliferations of cyanobacteria are often caused by high nutrient loading, and as such can serve as indicators of declining water quality. Massive industrialization in developing countries, like India, has polluted fresh water bodies, including wetlands. Many industries directly discard their effluents to nearby water sources without treatment. In the Sambalpur District of India effluents reach the reservoir of the worlds largest earthen dam i.e Hirakud Dam. This study examines cyanobacteria communities in the wetlands of Sambalpur District, Odisha, India, including areas subjected to industrial pollution. Result & Discussion The genera Anabaena, Oscillatoria, Chroococcus, Phormidium were dominant genera of polluted wetlands of Sambalpur districts. A positive correlation was found between total cyanobacterial species and dissolved oxygen levels, but cyanobacterial diversity was...

The activated sludge process is commonly used to treat wastewater by aerobic oxidation of organic pollutants into carbon dioxide and water. However, several nonoxidative mechanisms can also contribute to removal of organics. Sorption onto activated sludge can remove a large fraction of the colloidal and particulate wastewater organics. Intracellular storage of, e.g., polyhydroxyalkanoates (PHA), triacylglycerides (TAG), or wax esters can convert wastewater organics into precursors for high-value products. Recently, several environmental, economic, and technological drivers have stimulated research on nonoxidative removal of organics for wastewater treatment. In this paper, we review these nonoxidative removal mechanisms as well as the existing and emerging process configurations that make use of them for wastewater treatment. Better utilization of nonoxidative processes in activated sludge could reduce the wasteful aerobic oxidation of organic compounds and lead to more resourceefficient wastewater treatment plants.

An exopolysaccharide substances produced by Vibrio neocaledonicus sp. was introduced as a novel green inhibitor against the corrosion of carbon steel in artificial seawater and acidic media. The produced extracellular polymeric substance (EPS) is heterogeneous with composition of polysaccharides, nucleic acids and protein and average molecular weight of 29,572 Da. Adsorption of EPS on the metal surfaces and formation of Fe-EPS complexes acted as a barrier to prevent the oxygen penetration and hindered anodic and cathodic reactions. The inhibitory effect increases with increasing EPS concentration and exposure time. The highest corrosion inhibitory effect (95.1%) was observed for 10 g/L of EPS after 5 days of exposure in seawater. This is the highest inhibitory effect ever been reported by EPSs. While, the optimum concentration of EPS with the highest inhibition efficiency in 1 N H2SO4 was 1000 ppm. The influence of different parameters, such as initial pH, growth phase, various nitrogen and carbon sources on the production of EPS and its corrosion inhibitory effect were also investigated. 2 According to results, the optimum culture medium for EPS production is contained artificial seawater including 5% mannitol as carbon source and 0.1% (NH4)2SO4 as nitrogen source at pH=8. This medium could produce 22.24 g/L EPS during 3 days' incubation at 30°C. The corrosion inhibitory efficiency of obtained EPS was 95.97%.

Biofilms can cause severe problems to human health due to the high tolerance to antimicrobials; consequently, biofilm science and technology constitutes an important research field. Growing a relevant biofilm in the laboratory provides insights into the basic understanding of the biofilm life cycle including responses to antibiotic therapies. Therefore, the selection of an appropriate biofilm reactor is a critical decision, necessary to obtain reproducible and reliable in vitro results. A reactor should be chosen based upon the study goals and a balance between the pros and cons associated with its use and operational conditions that are as similar as possible to the clinical setting. However, standardization in biofilm studies is rare. This review will focus on the four reactors (Calgary biofilm device, Center for Disease Control biofilm reactor, drip flow biofilm reactor, and rotating disk reactor) approved by a standard setting organization (ASTM International) for biofilm experi...

A clean metal surface which contacts natural or industrial waters undergoes a series of processes that lead to the formation of inorganic deposits and biofilms. In these structures, microorganisms adhere irreversibly to the substrate, embedded in a matrix of extracellular polymeric substances (EPS). The problems arising from biofilm formation, such as microbiologically influenced corrosion (MIC), loss of equipment performance, product damages, generate economic costs and may lead to structural failures with consequences for operators and/or users. The aim of this study was to evaluate the corrosion associated with the formation of bacterial biofilms on carbon steel surfaces. Bacterial cultures used in the experiments were isolated from different systems that presented MIC. SAE 1010 carbon steel coupons were placed in cultures for biofilm development. After 48 h coupons were extracted and bacterial adherence was measured by viable bacteria counts, epifluorescence microscopy, crystal violet assay and EPS quantification. The biofilm morphology was analyzed by scanning electron microscopy (SEM) and epifuorescence microscopy. Surface deterioration was monitored using electrochemical impedance spectroscopy and open circuit potential measurements. Studies carried out allowed brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Servicio de Difusión de la Creación Intelectual correlating the adherence of the tested strains with the degree of attack suffered by the SAE 1010 carbon steel coupons.

Malva aegyptiaca L. (Malvaceae), a spontaneous plant used as a traditional medicine in Ghardaïa (Septentrional Sahara Algerian). This paper reports the extraction and partial characterization of water-soluble polysaccharides from M. aegyptiaca leaves. These polysaccharides were obtained by elimination of the ethanol extract and sequential extraction in distilled water, followed by precipitation in 75% ethanol. The yield of extract is 1.46% (w/w). The crude water soluble polysaccharide extracts were further characterized and revealed the average values 17.14 ± 1.43% proteins and 78.18±2.04% carbohydrates, among them 30.68±0.42% are uronic acid and 47.49±1.62% are neutral monosaccharides. The identification of monosaccharide composition by high performance anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD) methods shows 56.86% of galactose, 8.46% of rhamnose, 9.04% of arabinose, 5.05% of mannose and 20.57% of glucuronic acid.

Cyanobacterium Cyanothece sp. ATCC 51142 has been shown to produce an exopolysaccharide (EPS) at a high level. EPS production was found to be influenced by the concentration of salt, pH, and type of nitrogen source. Maximum polysaccharide production was found to occur at a 4.5% (w/v) NaCl salt concentration, pH 7.0, and in the presence of NaNO 3 as the nitrogen source. The gelation of EPS in alkaline conditions was employed to remove the dyes from the effluents. The effect of organic molecules and metal ions on the efficiency of dye removal capacity was investigated. A laboratory-scale reactor was prepared to treat artificial textile effluent.

Nitrifiers are known to form relatively dense and strong microcolonies in activated sludge flocs, but little is known about their adhesion characteristics and how these are relative to other floc components. The size distribution of ammonia and nitrite-oxidizing bacteria (Nitrosomonas oligotropha and Nitrospira spp.) in activated sludge from a nutrient removal plant showed that the majority of N. oligotropha cells formed microcolonies with a diameter of 13-22.5 mm, and most Nitrospira spp. cells formed microcolonies with a diameter of 9-22.5 mm. By applying high shear forces (2200 s À1), the largest microcolonies of N. oligotropha fragmented to a level well below the Kolmogorov microscale (approx. 15-25 mm). Only very little erosion of single cells took place. Nitrospira spp. microcolonies were generally slightly stronger than N. oligotropha. In order to characterize the adhesion/ binding mechanisms for the individual microcolonies, a number of different physicochemical treatments were combined with shear, and even though this did not lead to any explicit characterization of the species-specific adhesion mechanisms, entanglement of extracellular polymers was proposed as a plausible important adhesion mechanism. When compared to other floc components, the deflocculated fractions of N. oligotropha and Nitrospira spp. were much lower than those of cells in general (total cell count, DAPI) or the organic matter. Deflocculation of N. oligotropha ranged from 3% to 11% of the total N. oligotropha biovolume, Nitrospira spp. from 1% to 4% of the total Nitrospira spp. biovolume, whereas the number of deflocculated cells was 9-54% of the total cell count, and the deflocculated organic matter constituted 8-43% of the total amount of organic matter. These results clearly showed that activated sludge contained a large pool of loosely attached cells and extracellular polymeric substances, and that the nitrifiers and some other microcolony formers were very strong and remained almost intact even under extreme physical and chemical conditions.

Plastic particles from packaging, personal care products, synthetic clothing, and many other applications, are a potential risk to the ocean's health. Tiny, light particles of plastic can float on the sea surface for a long time. The sea surface is a special place: it is rich in chemical compounds produced by marine organisms below. Sometimes these substances make the sea surface appear as a shining, darker or brighter layer. The sea surface also connects the ocean and the atmosphere and controls important exchanges between those two systems, including the flow of oxygen, which is an essential element for life, and the flow of carbon dioxide, one of the main gases responsible for climate change. Plastic particles can increase the amount of chemical compounds in the sea surface layer, because marine microorganisms (like bacteria) may be more productive in the presence of plastic particles than they are in plastic-free environments. This increased production and bacterial activity can reduce the oxygen content of the water. We did a simple experiment to explore this mechanism.

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Biological activities in marine soft-sediments can modify the sedimentary environment through processes that change erosion rates. In low-energy environments, bioturbating macrofauna destabilizes sediments while microbes bind sediments and stabilize them. The degree to which these counteracting processes influence sediment movement in a physically dynamic environment has not been well quantified. In a field experiment, we established 56 (1 m 2) plots on an exposed intertidal sandflat. We used shade cloth and manipulated grazing pressure exerted by the deposit-feeding bivalve Macomona liliana (0−200 ind. m −2) to alter the microphytobenthic community. Three months post-manipulation, initiation of sediment transport (Ʈ c) and change in sediment erosion rate with increasing bed shear stress (m e) were measured. Mean grain size, density of the spionid polychaete Aonides trifida, density of adult M. liliana, and bulk carbohydrate concentration could account for 54% of the variation in Ʈ c (0.3−1.1 N m −2 s −1). Mean grain size was the only significant predictor (p ≤ 0.01) of m e explaining 22% of the variability (6−20 g N −1 s −1). Ʈ c was negatively correlated with density of several abundant shallow-dwelling bioturbators (indicating sediment destabilization), but we did not observe the expected increase in Ʈ c with microbial biomass. Furthermore, there was a positive correlation between adult M. liliana and Ʈ c as well as evidence for several positive feedbacks between abundant shallow-dwelling macrofauna and microbial biomass. These study results demonstrate that despite frequent reworking by tidal currents and waves, bioturbating macrofauna are important to initiating sediment transport regardless of their effects on microbial biomass.

Recovery followed by re-use of process-water obtained from dairy effluents by means of reverse osmosis technology is one route that can provide the dairy industry with the possibility to reach sustainable water regimes. However, membrane fouling is a phenomenon that limits both the efficiency and increases the running costs of such reverse osmosis units and can potentially alter the quality characteristics of permeate water. In this paper, several industrial-scale RO membranes used for recovery of process-water from whey UF permeate have been examined for their fouling tendency. At the end of a complete clean-in-place (CIP) protocol based on alkalineacid formulations, biofouling appears to be the main issue in the investigated RO-elements. Between 4.19 and 5.69 log 10 (CFU cm −2) of viable microorganisms still remained on the membrane retentate surface and, more surprisingly, evidence of significant contamination was found on permeate side of these particular membranes. Microbiological analysis indicate that minor loads of microorganisms do pass into the permeate streams but final UV treatments ensured final process-water with non-detectable levels. There is a need for optimization of cleaning procedures and finding the best compromise for achieving surface disinfection while still preserving membrane integrity and not compromising the water quality.

Environmental deterioration together with the need for water reuse and the increasingly restrictive legislation of water quality standards have led to a demand for compact, efficient and less energy consuming technologies for wastewater treatment. Aerobic granular sludge and membrane bioreactors (MBRs) are two technologies with several advantages, such as small footprint, high-microbial density and activity, ability to operate at high organic-and nitrogen-loading rates, and tolerance to toxicity. However, they also have some disadvantages. The aerobic granular sludge process generally requires post-treatment in order to fulfill effluent standards and MBRs suffer from fouling of the membranes. Integrating the two technologies could be a way of combining the advantages and addressing the main problems associated with both processes. The use of membranes to separate the aerobic granules from the treated water would ensure highquality effluents suitable for reuse. Moreover, the use of granular sludge in MBRs has been shown to reduce fouling. Several recent studies have shown that the aerobic granular membrane bioreactor (AGMBR) is a promising hybrid process with many attractive features. However, major challenges that have to be addressed include how to achieve granulation and maintain granular stability during continuous operation of reactors. This paper aims to review the current state of research on AGMBR technology while drawing attention to relevant findings and highlight current limitations.

A simple capillary electrophoretic method based on 1-phenyl-3-methyl-5-pyrazolon (PMP) derivatization has been developed for simultaneous separation and determination of nine aldoses (xylose, arabinose, glucose, rhamnose, fucose, galactose, mannose, glucuronic acid and galacturonic acid). The separation of PMP-labeled monosaccharide derivatives was carried out in uncoated capillary (48.5 cm؋75 m mm i.d.) and under the selected optimum conditions of pH 11.0, 200 mM borate buffer at applied voltage 15 kV and capillary temperature 20°C, the nine PMP-monosaccharides could be perfectly separated from each other within 40 min. Furthermore, the developed method was firstly applied to determine the sugar composition in the polysaccharide isolated from Chinese Codonopsis pilosula. The results showed that C. pilosula polysaccharide was a typically acidic heteropolysaccharide and was composed of arabinose, glucose, rhamnose, galactose, mannose, glucuronic acid and galacturonic acid in the molar contents of 48.

Glyphosate is a broad-spectrum systemic herbicide widely used to kill weeds in agricultural applications. However, the extensive and improper use of glyphosate leads to more significant health risks to the environment. Therefore, it is necessary to eliminate or minimize the concentrations of glyphosate in contaminated areas, which indigenous bacteria can do through bioremediation. Thus, this study aims to isolate and identify potential glyphosate degraders for future bioremediation. Bacteria were isolated from soil samples collected at a palm oil plantation that utilizes glyphosate as a source of carbon, phosphate, and energy sources. Overall, two bacterial isolates were isolated from the soil sample were screened and identified for their ability to utilize glyphosate by culturing in minimal salt media (MSM) supplemented with 0.05 M glyphosate for 30 days of incubation at 37 • C and pH 7. The growth of isolates was observed and analysed through the standard plate count method, and the pH value of the culture medium. The isolated bacteria were identified based on their morphological characteristics and 16S rDNA sequences. As a result, Isolate GP 1 and Isolate GP 2, identified as Bacillus tropicus strain UMTFA (GP1) and Proteus mirabilis strain UMTFA2 (GP2) had maximum growth (log phase) from day 9 until day 12 during the incubation period as compared to its controls. Hence, both strains of bacteria have the potential as glyphosate degraders. Therefore, the present study may provide a basis for bio-treatment and bioremediation of pesticide-contaminated soils and water. The authors recommend further studies on the analysis of the biodegradation rate and optimization of the glyphosate and bacterial culture concentration in enhancing the biodegradation of glyphosate.

I am so grateful to Dr. Komson Pirapatrungsuriya, for helping organize financial assistance for me during my candidature and for his readiness to encourage me to complete my thesis. I am also most grateful to Dr. Nathawut Thanee for his sincere encouragement, great understanding and kind support that he provided me throughout my stay at SUT. In addition, I would like to thank Mr.Goswami (CAMO/ASIA), India for kindly providing Unscrambler software which was essential for the analysis of the spectroscopic data. My thanks also go to Dr. Tanya Livshults (Harward University, USA), for help on proof reading the thesis report and for kind encouragement. I also deeply appreciated the family of Assoc. Prof. Dr. Tawit Chithsomboon for financial support for my last period of study in SUT. I extend my sincere thanks to Assoc. Prof. Dr. Kinith Kaimook for kind assistance on statistics My special gratitude goes to the National University of Lao for providing me the opportunity to pursue my Ph.D. program and providing funds through Asia VI Development Bank to support my study. My special thanks go to the Russell E. Train, Education for Nature Program (WWF) for the continuous financial support they provided to me to complete my thesis. I also thank to SUT and School of Biology for giving me opportunity to perform my Ph.D. program, for all the facilities, and for warm hospitality. My thanks and great appreciation to Asst. Prof. Dr. Sirikhae Pongsawat as well as Mr. Suwit, Mr. Pongnarin, Ms. Petchara, Mr. Chaiwat, Ms. Nouanpang, Ms. Nattika and Ms. Pornthip from SUT for their friendship and kind help. I would like to especially thank Ms. Manichanh, Ms. Chanhsom and all my friends in Laos for their great friendship, deep understanding and warmest encouragement that helped me succeed at my studies at SUT. Last but not least, I would like to express my deepest gratitude to my mother, father and my children for their great love, understanding and assistance they provided that helped me to overcome some very difficult personal events that occurred during my candidature, which enabled me to complete my study. Above all, I owe a debt of gratitude to my deceased husband for his great love, support for my wishes, and his helpful understanding during my precious time with him.

Water scarcity in Iran has worsened as a result of population growth, increasing pollution, poor water management practices, and climate change. Using proper utilization and management of wastewater can provide the ability to cope with pollution threats and take the opportunity to benefit from the new sources of water. In this study, the impact of water scarcity on the production and macroeconomics indicators in Iranian economy was analyzed and in the social appraisal, the relationship between the household poverty and the source of drinking water and sewage disposal unit was evaluated. The results show that in the optimistic scenario, the economic losses of water scarcity is estimated 34000 billion Rials. As a result, an investment in the water efficiency improving programs and water reuse projects is a beneficial strategy for coping with economic losses of water shortages. Furthermore, poverty is more prevalent in the households with no access to public water supply network and se...

While phytoplankton has been shown to influence climate in diverse ways, this review treats just two aspects: reduction of sea-air fluxes, and increase in ocean foam coverage. Plankton and neuston algae produce dissolved organic matter (DOM), which tends to concentrate in the seasurface microlayer (SML). Fluxes of matter and energy exchange across the sea-air surface and are important in regulating weather and climate. Freshly produced DOM shows marked surface and rheological activity, and it reduces these fluxes. Foam covers part of the ocean surface, largely produced by breaking and spilling waves. Its longevity is increased in areas subject to high biological productivity, and particularly during blooms of some species of harmful algae and may involve specific DOM molecules and the algal genes that produce them. Ocean foam is generally white and reflects about 50% of incident solar radiation, while the foam-free ocean surface reflects only about 5%. Thus, algal DOM helps to cool the planet by increasing foam coverage. Unpredictable changes in abundance and taxonomic composition of phytoplankton and phytoneuston may be adding uncertainty to modelling global and local climate. Further research on the roles of the ocean in climate regulation should thus pay more attention to algal communities, their specific genes and the physical and chemical characteristics of the DOM they produce.

The use of microalgae in biological wastewater treatment has been widely studied. However, there is a dearth of information about estimating the microalgae and bacteria concentrations. In order to maintain a stable algal-bacterial system, it is necessary to quantify both the algal and bacterial biomasses. Typically, microalgae and bacteria from flocs in activated sludge contribute to better biomass settleability. However, flocs cause problems when it comes to estimating the individual biomass concentrations of microalgae and bacteria in a symbiotic algae-bacteria aggregate. This study aimed to find the best disintegration treatment with low influence on the viability of the microalgal cell determined by its photosynthetic activity. In the present work, biological (enzyme solution), chemical (formaldehyde), mechanical (glass bead-beating), and physical (sonication) treatments were performed on microalgae-bacteria flocs (ALBA flocs) to disintegrate the community as a pre-treatment step in order to develop a method for estimating the algal and bacterial concentration and to quantify the degree of disintegration. The effectiveness of the methods to disintegrate ALBA flocs in descending order are the following: sonication, bead-beating, formaldehyde and enzyme application. Sonication treatment (40 W, 6 min) showed the best disintegration performance of the microalgal-bacterial flocs, up to 90 % with 17 % loss of the algal photosynthetic activity. Bead-beating (3 mm diameter, 80 s) achieved 80 % of disintegration with only 6 % loss of its photosynthetic activity. These results demonstrate the possibility of mild disintegration of compact ALBA flocs without having any adverse impact on the microalgae cell. After these treatments, it becomes possible to estimate the individual biomass concentrations of algae and bacteria manually such as with a cell-counting chamber.