Pure Cultures

A note on algae as potential source for alternate fuels – Biodiesel 1E.Manoj Kumar, 2D. Jagadish & R. Bharath Kumar*1 1School of Biotechnology& 2Mechanical Engineering, Vignan’s University, Vadlamudi, Guntur Dist., Andhra Pradesh 522213 *Corres.author: enamalamanoj0107@gmail.com,djagadish.009@gmail.com, drbharathravuru@gmail.com Ph.9346986845 Abstract: In the view of faster rates of depletion of fossil fuels and increased energy demand the world is looking for clean alternate fuels. Many researchers are exploring new ways of exploring the potent fuels like biofuels from various sources. The most used sources for the production of biofuels are the plants. Due to the inconsistency and cost effectiveness of the production of seeds for biodiesel production, the attention is now shifted to many other natural resources. Our rich source of algal and planktonic wealth has been providing niche for satisfying the future demands. A meagre amount of work has been carried out in this potential a...

Global research is moving forward in developing hydrogen as a renewable energy source in order to alleviate concerns related to carbon dioxide emissions and depleting fossil fuels resources. Biohydrogen has the potential to replace current hydrogen production technologies relying heavily on fossil fuels. Batch and continuous systems employing pure mesophiles and thermophiles isolates and co-cultures of isolates have been investigated. The co-cultures of the isolates achieved better results than mono-cultures of the isolates with respect to different parameters. This paper presents a critical review of the literature reporting on fermentative biohydrogen production by pure cultures of bacteria in different systems. Synergies between different types of bacteria, i.e. strict and facultative, and a comparison between mono-and co-cultures, types of feedstocks, and preferred feedstocks for mono-and cultures are outlined.

Sustainable biofuels, biomaterials, and fine chemicals production is a critical matter that research teams around the globe are focusing on nowadays. Polyhydroxyalkanoates represent one of the biomaterials of the future due to their physicochemical properties, biodegradability, and biocompatibility. Designing efficient and economic bioprocesses, combined with the respective social and environmental benefits, has brought together scientists from different backgrounds highlighting the multidisciplinary character of such a venture. In the current review, challenges and opportunities regarding polyhydroxyalkanoate production are presented and discussed, covering key steps of their overall production process by applying pure and mixed culture biotechnology, from raw bioprocess development to downstream processing.

Global research is moving forward in developing hydrogen as a renewable energy source in order to alleviate concerns related to carbon dioxide emissions and depleting fossil fuels resources. Biohydrogen has the potential to replace current hydrogen production technologies relying heavily on fossil fuels. Batch and continuous systems employing pure mesophiles and thermophiles isolates and co-cultures of isolates have been investigated. The co-cultures of the isolates achieved better results than mono-cultures of the isolates with respect to different parameters. This paper presents a critical review of the literature reporting on fermentative biohydrogen production by pure cultures of bacteria in different systems. Synergies between different types of bacteria, i.e. strict and facultative, and a comparison between mono-and co-cultures, types of feedstocks, and preferred feedstocks for mono-and cultures are outlined.

Resumo-Fatores que influenciam a produção de hidrogênio por processos fermentativos. A crescente preocupação com a substituição de combustíveis fósseis tem incentivado a busca de novas formas de produção de energia limpa. O hidrogênio tem-se destacado como uma forma ideal de energia, pois não contribui para o aumento do efeito estufa além de possuir alto poder calorífico. A produção microbiológica deste gás é um processo que pode se tornar sustentável do ponto de vista social, ambiental e econômico, uma vez que microrganismos isolados do ambiente podem utilizar resíduos provenientes de processos industriais e agrícolas. Diversos microrganismos são descritos na literatura como produtores de hidrogênio, principalmente os gêneros Clostridium e Enterobacter, a partir de diversos tipos de substratos. Porém, diversos fatores e condições fermentativas que irão direcionar para a rota metabólica de produção de hidrogênio devem ser analisados. Dessa forma, o objetivo deste trabalho é contribuir com o estado da arte, fazendo uma revisão dos recentes trabalhos envolvendo a produção microbiológica de hidrogênio e os principais aspectos envolvidos no processo biotecnológico. Palavras chaves-Biohidrogênio. Microrganismo. Fermentação. Substrato. Resíduo. pH. Temperatura.

A holistic approach for the optimum exploitation of biomass resources for food, energy and other products will provide the key for a sustainable bio-based future in EU. The small and medium scale applications are expected to play a crucial role in this direction in the future, due to their flexibility and adaptability to the regional and local conditions. The increasing biomass demand and socioenvironmental concerns for bioenergy applications require the development of a framework of "Best Practices" for any new application entering the system, in order to ensure its techno-economic feasibility and socio-environmental sustainability. In the present work such a framework will be developed and presented, and it will be specified for the two-step fermentative biohydrogen generation technology. Under this point of view, a "Best Practice" guide is developed for each of the 4 previously selected, most suitable for the examined technology feedstocks, i.e. sugar beet, potato steam peels, barley straw and wheat bran. An outline with main points referring to both sugar beet and barley straw is presented in this work.

Thermoanaerobacterium aciditolerans bacterium Trau DAt isolated in Vietnam had the hydrogen production capability under the anaerobic condition at 55 o C. Using glucose, the dark fermentation of strain Trau DAt for hydrogen production was performed in three different scales: the flask scales under the suitable (1) and optimal (2) conditions, and the automatic fermentor system Bio-Flo 110 (3). Under the suitable condition, the strain Trau DAt produced 330 ml volume total gas (L-1) and hydrogen occupied 42.95% of gas total. Under the optimal condition, the maximum volume total gas of 701 ml (L-1) was obtained and hydrogen occupied of 77.2% total volume gas. Based on results of RSM analysis and pH controlled examination, the dark fermentation of strain Trau DAt was performed under automatic fermentor system scale (Bio-Flo 110). 2.64 L total gas (L-1) was obtained by consuming 92.58% glucose and hydrogen volume occupied 94.85% of gas total. The maximum hydrogen yield of strain Trau DAt was 1.63 mol H2 (mol glucose)-1. Obtained results showed the remarkable potentiality of Trau DAt strain in application to the larger fermentation scale for biohydrogen production in Vietnam.

Thermoanaerobacterium aciditolerans bacterium Trau DAt isolated in Vietnam had the hydrogen production capability under the anaerobic condition at 55 o C. Using glucose, the dark fermentation of strain Trau DAt for hydrogen production was performed in three different scales: the flask scales under the suitable (1) and optimal (2) conditions, and the automatic fermentor system Bio-Flo 110 (3). Under the suitable condition, the strain Trau DAt produced 330 ml volume total gas (L-1) and hydrogen occupied 42.95% of gas total. Under the optimal condition, the maximum volume total gas of 701 ml (L-1) was obtained and hydrogen occupied of 77.2% total volume gas. Based on results of RSM analysis and pH controlled examination, the dark fermentation of strain Trau DAt was performed under automatic fermentor system scale (Bio-Flo 110). 2.64 L total gas (L-1) was obtained by consuming 92.58% glucose and hydrogen volume occupied 94.85% of gas total. The maximum hydrogen yield of strain Trau DAt was 1.63 mol H2 (mol glucose)-1. Obtained results showed the remarkable potentiality of Trau DAt strain in application to the larger fermentation scale for biohydrogen production in Vietnam.

2-Phenoxyethanol is converted into phenol and acetate by a strictly anaerobic Gram-positive bacterium, Acetobacterium strain LuPhet1. Acetate results from oxidation of acetaldehyde that is the early product of the biodegradation process (Frings, J., and Schink, B. (1994) Arch. Microbiol. 162, 199-204). Feeding experiments with resting cell suspensions and 2-phenoxyethanol bearing two deuterium atoms at either carbon of the glycolic moiety as substrate demonstrated that the carbonyl group of the acetate derives from the alcoholic function and the methyl group derives from the adjacent carbon. A concomitant migration of a deuterium atom from C-1 to C-2 was observed. These findings were confirmed by NMR analysis of the acetate obtained by fermentation of 2-phenoxy-[2-13 C,1-2 H 2 ]ethanol, 2-phenoxy-[1-13 C,1-2 H 2 ]ethanol, and 2-phenoxy-[1,2-13 C 2 ,1-2 H 2 ]ethanol. During the course of the biotransformation process, the molecular integrity of the glycolic unit was completely retained, no loss of the migrating deuterium occurred by exchange with the medium, and the 1,2deuterium shift was intramolecular. A diol dehydrataselike mechanism could explain the enzymatic cleavage of the ether bond of 2-phenoxyethanol, provided that an intramolecular H/OC 6 H 5 exchange is assumed, giving rise to the hemiacetal precursor of acetaldehyde. However, an alternative mechanism is proposed that is supported by the well recognized propensity of ␣-hydroxyradical and of its conjugate base (ketyl anion) to eliminate a ␤-positioned leaving group. Ether linkages are comparably stable, and their cleavage requires rather rigorous conditions. Such cleavage reactions represent challenges also to microbes and their enzymes, and this difficulty causes the relative stability of many ether compounds in nature (1). An important group of xenobiotic ether compounds, the linear polyether PEG 1 and its derivatives, is released into the * This work was supported in part by a grant from the Deutsche Forschungsgemeinschaft, Bonn in its priority program "Radicals in enzymatic catalysis." The costs of publication of this article were defrayed in part by the payment of page charges.

Thermoanaerobacterium aciditolerans bacterium Trau DAt isolated in Vietnam had the hydrogen production capability under the anaerobic condition at 55 o C. Using glucose, the dark fermentation of strain Trau DAt for hydrogen production was performed in three different scales: the flask scales under the suitable (1) and optimal (2) conditions, and the automatic fermentor system Bio-Flo 110 (3). Under the suitable condition, the strain Trau DAt produced 330 ml volume total gas (L-1) and hydrogen occupied 42.95% of gas total. Under the optimal condition, the maximum volume total gas of 701 ml (L-1) was obtained and hydrogen occupied of 77.2% total volume gas. Based on results of RSM analysis and pH controlled examination, the dark fermentation of strain Trau DAt was performed under automatic fermentor system scale (Bio-Flo 110). 2.64 L total gas (L-1) was obtained by consuming 92.58% glucose and hydrogen volume occupied 94.85% of gas total. The maximum hydrogen yield of strain Trau DAt was 1.63 mol H2 (mol glucose)-1. Obtained results showed the remarkable potentiality of Trau DAt strain in application to the larger fermentation scale for biohydrogen production in Vietnam.

The present review article aims to summarize the microbiological and technological background of the dark fermentation processes for hydrogen generation, emphasising on the exploitation of biomass and wastes as potential feedstocks. The basic principles, the microbiology and the current technology of the processes are outlined. Subsequently, the use of different types of biomass and wastes that have so far been tested as feedstocks is analysed focusing on the advantages, possible limitations and future prospects of their exploitation. Moreover, different types of so far suggested pretreatment methods for better utilisation of the feedstocks are presented, pointing out the advantages and disadvantages of each method. Finally, methods for possible further utilisation of the generated by-products are laid out as well as the present status of the real scale applications.

Global research is moving forward in developing hydrogen as a renewable energy source in order to alleviate concerns related to carbon dioxide emissions and depleting fossil fuels resources. Biohydrogen has the potential to replace current hydrogen production technologies relying heavily on fossil fuels. Batch and continuous systems employing pure mesophiles and thermophiles isolates and co-cultures of isolates have been investigated. The co-cultures of the isolates achieved better results than mono-cultures of the isolates with respect to different parameters. This paper presents a critical review of the literature reporting on fermentative biohydrogen production by pure cultures of bacteria in different systems. Synergies between different types of bacteria, i.e. strict and facultative, and a comparison between mono-and co-cultures, types of feedstocks, and preferred feedstocks for mono-and cultures are outlined.

Physicochemical pretreatment of lignocellulosic corn fruit wastes (husk, shank, stalk) has been done. E. coli K12 growth, ORP kinetics, and H2 production were followed upon utilization of corn waste hydrolysates (CWH) separately and their mixture. During the bacterial log growth phase with the decrease of medium pH the readings of Pt electrode from positive to low negative values (~ –450±10 mV) were observed, with the yield ~ 0.75 mmol H2 /L and 0.29 bacterial cell dry weight g/L biomass in CWH based medium. Meat (chicken wastes) broth supplementation ~2 fold enhanced both E. coli biomass formation and H2 production on CWH mixture.

Background Owing to the high growth rate, high protein and carbohydrate contents, and an ability to grow autotrophically, microalgal biomass is regarded as a promising feedstock for fermentative hydrogen production. However, the rigid cell wall of microalgae impedes efficient hydrolysis of the biomass, resulting in low availability of assimilable nutrients and, consequently, low hydrogen production. Therefore, pretreatment of the biomass is necessary in order to achieve higher hydrogen yield (HY). In the present study, acid-thermal pretreatment of Chlorella sp. biomass was investigated. Conditions for the pretreatment, as well as those for hydrogen production from the pretreated biomass, were optimized. Acid pretreatment was also conducted for comparison. Results Under optimum conditions (0.75% (v/v) H2SO4, 160 °C, 30 min, and 40 g-biomass/L), acid-thermal pretreatment yielded 151.8 mg-reducing-sugar/g-biomass. This was around 15 times that obtained from the acid pretreatment under ...

Global research is moving forward in developing hydrogen as a renewable energy source in order to alleviate concerns related to carbon dioxide emissions and depleting fossil fuels resources. Biohydrogen has the potential to replace current hydrogen production technologies relying heavily on fossil fuels. Batch and continuous systems employing pure
mesophiles and thermophiles isolates and co-cultures of isolates have been investigated. The co-cultures of the isolates achieved better results than mono-cultures of the isolates with respect to different parameters. This paper presents a critical review of the literature reporting on fermentative biohydrogen production by pure cultures of bacteria in different systems. Synergies between different types of bacteria, i.e. strict and facultative, and a comparison between mono- and co-cultures, types of feedstocks, and preferred feedstocks for mono- and cultures are outlined.

The aim of the present study is to investigate the feasibility of exploiting olive oil mill wastewater (OOMW) for PHAs production by pure culture of Pseudomonas sp. Four different strains belonging to the Pseudomonas genus were isolated from an ‘enriched’ mixed culture that was developed using activated sludge from the municipal wastewater treatment plant of the city of Patras (Greece) as inoculum. The enrichment was performed by subjecting the culture to sequential cycles of carbon and nitrogen limitation to ensure that the predominant strains would be PHAs forming bacteria.
To estimate the maximum capacity of PHAs production under favorable conditions, batch experiments were carried out under nitrogen limitation and continuous aeration using synthetic substrate with volatile fatty acids (VFAs) that is acetate, propionate, butyrate as carbon source with both mixed culture as well as all isolates.
It was shown that the mixed culture had the best performance as far as PHAs yield is concerned (g PHAs produced/g VFAs consumed) whereas in terms of final PHAs content (g PHAs/g of cell dry mass) one of the four isolates proved to be more efficient. It is also noticeable that although butyrate was preferably consumed from the mixed culture all isolates tested tended to consume acids of smaller molecular weight first, thus indicating that the mixed culture comprises from other microorganisms too.
To comparatively evaluate the behavior of the mixed and pure
cultures when instead of synthetic substrate a real waste is supplied
as feedstock for PHAs production, batch experiments with acidified
OOMW were conducted.
The acidification of OOMW was accomplished via anaerobic fermentation using a mesophilic (35◦C) CSTR-type bioreactor. The effluent of the reactor (acidified OOMW) which was rich in VFAs was filtered and sterilized to be used as substrate for PHAs production under nitrogen limitation and continuous aeration. As expected, the behavior of the cultures was the same in all cases in terms of substrate preference. The achieved yields though were lower compared to the respective ones when synthetic substrate was used, which could be attributed to the complexity of the wastewater or to inhibitory effect of ‘toxic’ compounds present in OOMW, such as polyphenols.