Actinobacterial Taxonomy

Microbial pigments are generally preferred to other natural pigments due to their easy scaling up, quick pigment extraction methods and simple culturing processes. Hence, the objective of this paper was to isolate and identify yellow pigment producing rod-shaped bacterium from farm soil in Alimosho Local Government Area, Lagos State, Nigeria using appropriate microbial and analytical standard procedures. The identification of the isolate revealed a Gram positive yellow pigment producing rod-shaped bacterium as Brevibacterium iodinum. The optimal conditions for pigment production by the B. iodinum was achieved in nutrient broth at pH7, 35°C under shaking condition (120rpm) using 5% inoculum of 0.4 OD (600nm). At these optimal conditions, 1.2g/L of biomass produced a total of 0.225g/L of crude pigment. The yellow pigment showed maximum absorption at 455nm. The GC-MS analysis of the crude pigment revealed major compounds such as methenamine; cis-10-Heptadecenoic acid, methyl ester; acetic acid, 2-[bis(methylthio)methylene]-1-phenylhydrazide and 4-Methyl-2-trimethylsilyloxyacetophenone This study has shown that B. iodinum produces a bacterial pigment which can be explored for different industrial applications.

There is growing interest in the antimicrobial discovery of life-threatening multidrug-resistant pathogens. The study was undertaken to isolate, identify, and characterize antibiotic-producing actinomycetaceae, particularly nocadisosaceae, from soil samples of Bingol, Turkey. Soil samples were collected from three different regions of Bingol, Turkey. The physicochemical analysis of the soil samples was immediately measured using standard methods. This was followed by isolation of Nocardiopsaceae, nutritional tests, chemotaxonomic analysis, and molecular characterization. The isolated organisms showed morphological properties consistent with the Nocardiopsaceae soil bacteria. The 16s rDNA gene sequence indicated a similarity between the strains with 99.86% which was Nocardiopsaceae synnemata-formans. The BLAST hits had a significant e-value of 0.005. The results of the present study revealed that soil Nocardiopsaceae of Bingol appears to have immense potential as a source of antibacterial compounds.

"Actinobacteria" are of significant economic value to mankind since agriculture and forestry depend on their soil system contribution. The organic stuff of deceased creatures is broken down into soil, and plants are able to take the molecule up again. Actinobacteria can be used for sustainable agriculture as biofertilizers for the improvement of plant growth or soil health by promoting different plant growth attributes, such as phosphorus and potassium solubilization, production of ironchelating compounds, phytohormones, and biological nitrogen attachment even under the circumstances of natural and abiotic stress. Nanotechnology has received considerable interest in recent years due to its predicted impacts on several key fields such as health, energy, electronics, and the space industries. Actinobacterial biosynthesis of nanoparticles is a dependable, environmentally benign, and significant element toward green chemistry, which links together microbial biotechnology and nanobiology. Actinobacterial-produced antibiotics are common in nearly all of the medical treatments, and they are also recognized to aid in the biosynthesis of excellent surface and size properties of nanoparticles. Bioremediation using microorganisms is relatively safe and more efficient. Actinobacteria use carbon toxins to synthesize economically viable antibiotics, enzymes, and proteins as well. These bacteria are the leading microbial phyla that are beneficial for deterioration and transformation of organic and metal substrates.

This article emphasizes the various contributions of actinobacteria to the well-being of human life on our planet. Agrarian virtues begin with the substitution of chemical fertilizers with bio-fertilizing microorganisms which have a versatile potential for the benefit of soil and plants by playing complementary and interconnected roles. Thus, these microorganisms improve soil health through bioremediation phenomena and the elimination of several non-beneficial microorganisms. In agriculture, these microorganisms can be added to compost as inoculants to speed up the composting process and provide an additional source of beneficial microorganisms for the compost-treated soil. Streptomyces and other actinobacteria can also be used as biotechnological sources of herbicides and insecticides. In the medical and therapeutic sectors, this paper emphasizes the potential of actinobacteria, in particular Streptomyces species, in the production of antibiotics, antioxidant, and anticancer agents...

The Sahara, one of the most extreme environments on Earth, constitutes an unexplored source of alkalitolerant actinobacteria. ln this worl<, we studied the diversity of alkalitolerant actinobacteria in various soils collected from different regions of the Algerian Sahara. A total of 29 alkalitolerant actinobacterial strains were isolated by using a complex agar medium. The diversity of these acti nobacteria was evaluated using a polyphasic approach, which included morphological, chemotaxo nomic, physiological (numerical taxonomy) and 16S rRNA gene analyses. The isolates which were assigned to the genus Nocardiopsis, shared relatively low 16S rRNA gene sequences similarities compared to closely related species suggesting that they belonged to putatively new species. Ali of the strains were tested for antibiotic activity against a broad range of microorganisms and screened for genes encoding polyketide synthases and non-ribosomal peptide synthetases and found to have the potential to produce secondary metabolites. Consequently, the study supports the view that extrerne environments contain many nove! actinobacteria, which represent an unex plored source for the discovery of biologically active compounds.

The halophilic actinomycete genus Streptomonospora, forming a distinct branch in the 16S rRNA gene phylogenetic tree adjacent to the genera Nocardiopsis and Thermobifida, was first proposed by Cui et al. to accommodate the species type Streptomonospora salina. During a biodiversity and taxonomic study on halophilic filamentous actinomycetes from a saline lake in western China, numerous new halophilic actinomycetes strains were isolated. To confirm whether they are members of the genus Streptomonospora, one set of genus-specific oligonucleotides was designed which allows rapid detection of members of the genus Streptomonospora by means of PCR amplification. The genus specificity of these primers was validated with reference strains as well as with wild-type isolates, which exhibited morphological characteristics common to this genus.

Strain M2T was isolated from the beach of Cuxhaven, Wadden Sea, Germany, in course of a program to attain new producers of bioactive natural products. Strain M2T produces litoralimycin and sulfomycin-type thiopeptides. Bioinformatic analysis revealed a potential biosynthetic gene cluster encoding for the M2T thiopeptides. The strain is Gram-stain-positive, rod shaped, non-motile, spore forming, showing a yellow colony color and forms extensively branched substrate mycelium and aerial hyphae. Inferred from the 16S rRNA gene phylogeny strain M2T affiliates with the genus Streptomonospora. It shows 96.6% 16S rRNA gene sequence similarity to the type species Streptomonospora salina DSM 44593 T and forms a distinct branch with Streptomonospora sediminis DSM 45723 T with 97.0% 16S rRNA gene sequence similarity. Genome-based phylogenetic analysis revealed that M2T is closely related to Streptomonospora alba YIM 90003 T with a digital DNA-DNA hybridisation (dDDH) value of 26.6%. The predomi...

compounds to oxidizing reduced inorganic compounds within the cave rocks. More importantly, the microbial diversity encountered was surprisingly high compared to what was expected given the amount and complexity of nutrients available in subterranean environments. This apparent violation of competitive exclusion or the 'one species-one niche' requirement (Hardin, 1960) led scientists to believe that within caves the selfish competition for resources is replaced by more cooperative and mutualistic microbial associations (Barton & Jurado, 2007). One eye-catching example of cave microbes are those found in Karstic and in lava caves which morphologically resemble white, yellow, grey, or pink bacterial colonies. Where present, these colonies can be observed throughout the cave as distinct one-millimetre

compounds to oxidizing reduced inorganic compounds within the cave rocks. More importantly, the microbial diversity encountered was surprisingly high compared to what was expected given the amount and complexity of nutrients available in subterranean environments. This apparent violation of competitive exclusion or the 'one species-one niche' requirement (Hardin, 1960) led scientists to believe that within caves the selfish competition for resources is replaced by more cooperative and mutualistic microbial associations (Barton & Jurado, 2007). One eye-catching example of cave microbes are those found in Karstic and in lava caves which morphologically resemble white, yellow, grey, or pink bacterial colonies. Where present, these colonies can be observed throughout the cave as distinct one-millimetre

Aims: Angiogenesis is a physiological process that has important impacts on the pathology and healing of various diseases, and its induction or inhibition by bioactive actinobacterial metabolites can help the treatment of some diseases. In this study, the effects of actinobacterial extract in the process of angiogenesis have been explored. Methods and Results: In this research, proangiogenic and antiangiogenic metabolites producing actinobacteria were isolated from soil samples and their fermentation broth were extracted and after evaluation of their toxicity by MTT assay, antiangiogenic and proangiogenic activities were screened against human umbilical vein endothelial cells (HUVECs) by in vitro tube formation and migration assay. Isolated strains were identified through molecular techniques. The results showed that Nocardiopsis arvandica UTMC 103 and Nonomuraea sp. UTMC 2180 extracts had a high potential of anti-angiogenic activity on HUVECs. Conclusions: For the first time proangiogenic potency of a rare actinobacterium, Kribbella sp. UTMC 522, was reported, and N. arvandica UTMC 103 and Nonomuraea sp. UTMC 2180 extracts inhibits the proliferation, migration and angiogenesis activity of HUVECs with reasonable potency. Significance and Impact of the Study: Metabolites of the introduced rare actinobacteria are potent proangiogenic and angiogenic inhibitors. Identification of angiogenic-antiangiogenic mechanisms and purification of the extracts would be useful in therapeutic angiogenesis.

Liquid chromatography coupled with high resolution mass spectrometry (LC-HRESMS)-assisted metabolomic profiling of two sponge-associated actinomycetes, Micromonospora sp. UR56 and Actinokineospora sp. EG49, revealed that the co-culture of these two actinomycetes induced the accumulation of metabolites that were not traced in their axenic cultures. Dereplication suggested that phenazine-derived compounds were the main induced metabolites. Hence, following large-scale co-fermentation, the major induced metabolites were isolated and structurally characterized as the already known dimethyl phenazine-1,6-dicarboxylate (1), phenazine-1,6-dicarboxylic acid mono methyl ester (phencomycin; 2), phenazine-1-carboxylic acid (tubermycin; 3), N-(2-hydroxyphenyl)-acetamide (9), and p-anisamide (10). Subsequently, the antibacterial, antibiofilm, and cytotoxic properties of these metabolites (1-3, 9, and 10) were determined in vitro. All the tested compounds except 9 showed high to moderate antibacterial and antibiofilm activities, whereas their cytotoxic effects were modest. Testing against Staphylococcus DNA gyrase-B and pyruvate kinase as possible molecular targets together with binding mode studies showed that compounds 1-3 could exert their bacterial inhibitory activities through the inhibition of both enzymes. Moreover, their structural differences, particularly the substitution at C-1 and C-6, played a crucial role in the determination of their inhibitory spectra and potency. In conclusion, the present study highlighted that microbial co-cultivation is an efficient tool for the discovery of new antimicrobial candidates and indicated phenazines as potential lead compounds for further development as antibiotic scaffold.

Liquid chromatography coupled with high resolution mass spectrometry (LC-HRESMS)-assisted metabolomic profiling of two sponge-associated actinomycetes, Micromonospora sp. UR56 and Actinokineospora sp. EG49, revealed that the co-culture of these two actinomycetes induced the accumulation of metabolites that were not traced in their axenic cultures. Dereplication suggested that phenazine-derived compounds were the main induced metabolites. Hence, following large-scale co-fermentation, the major induced metabolites were isolated and structurally characterized as the already known dimethyl phenazine-1,6-dicarboxylate (1), phenazine-1,6-dicarboxylic acid mono methyl ester (phencomycin; 2), phenazine-1-carboxylic acid (tubermycin; 3), N-(2-hydroxyphenyl)-acetamide (9), and p-anisamide (10). Subsequently, the antibacterial, antibiofilm, and cytotoxic properties of these metabolites (1–3, 9, and 10) were determined in vitro. All the tested compounds except 9 showed high to moderate antibact...

Bacterial resistance to different antimicrobial agents is growing with alarming speed, especially when bacterial cells are living in biofilm. Hybrid nanoparticles, synthesized through the green method, hold promise as a potential solution to this challenge. In this study, 66 actinomycete strains were isolated from three distinct marine sources: marine sediment, the algae Codium bursa, and the marine sponge Chondrosia reniformis. From the entirety of the isolated strains, one strain, S26, identified as Saccharopolyspora erythrea, was selected based on its taxonomic position and significant antimicrobial activity. Using the biomass of the selected marine Actinobacteria, the green synthesis of eco-friendly silver carbonate nanoparticles (BioAg2CO3NPs) is reported for the first time in this pioneering study. The BioAg2CO3NPs were characterized using different spectroscopic and microscopic analyses; the synthesized BioAg2CO3NPs primarily exhibit a triangular shape, with an approximate size of 100 nm. Biological activity evaluation indicated that the BioAg2CO3NPs exhibited good antimicrobial activity against all tested microorganisms and were able to remove 58% of the biofilm formed by the Klebsiella pneumoniae kp6 strain.

Isoptericola sp. AK164 is a Gram-positive, aerobic bacterial genus from the family Promicromonosporaceae, isolated from the root rhizosphere of Avicennia marina. AK164 significantly enhanced the growth of the Arabidopsis thaliana plant under normal and saline conditions. These bacteria can produce ACC deaminase and several enzymes playing a role in carbohydrate hydrolyses, such as cellulose, hemicellulose, and chitin degradation, which may contribute to plant growth, salt tolerance, and stress elevation. The genome sequence AK164 has a single circular chromosome of approximately 3.57 Mbp with a GC content of 73.53%. A whole genome sequence comparison of AK164 with type strains from the same genus, using digital DNA–DNA hybridization and average nucleotide identity calculations, revealed that AK164 might potentially belong to a new species of Isoptericola. Genome data and biochemical analyses indicate that AK164 could be a potential biostimulant for improving agriculture in submerged...

The ocean is considered to be an immense reservoir of biological and microbial diversity on the planet. In marine biospheres, microbial communities are ecologically significant as intermediaries of energy. By decomposing the dead as well as decaying organic matter with the assistance of microbial communities, it plays an indispensable role in the nutrient regeneration cycles of marine ecosystems. Marine environments associated with microorganisms such as bacteria, fungi, and bacterial virus have renowned potential to produce novel bioactive natural products and chemically diverse secondary metabolites like antibiotics, antifungal, antiviral, antitumor, anticancer, and also different hydrolyzing enzymes, namely, protease, lipase, amylase, chitinase, etc. Hence, the bioprospecting for these compounds is of greater importance. Numerous effective and efficient applications of marine microbial metabolites contribute to the fields of pharmaceuticals, biotechnological, agricultural, cosmet...

Actinomycetes inhabit both terrestrial and marine ecosystems and are highly proficient in producing a wide range of natural products with diverse biological functions, including antitumor, immunosuppressive, antimicrobial, and antiviral activities. In this review, we delve into the life cycle, ecology, taxonomy, and classification of actinomycetes, as well as their varied bioactive metabolites recently discovered between 2015 and 2023. Additionally, we explore promising strategies to unveil and investigate new bioactive metabolites, encompassing genome mining, activation of silent genes through signal molecules, and co-cultivation approaches. By presenting this comprehensive and up-to-date review, we hope to offer a potential solution to uncover novel bioactive compounds with essential activities.

The disadvantages associated with conventional treatment of crude oil pollution have led to the development of alternative, economical and reliable biological treatments. In this study, six actinobacterial isolates were obtained from 120cm soil depth of a selected crude oil contaminated site in the Niger Delta region of Nigeria. Streptomyces albus was selected from the six isolates based on its comparative ability to growth on crude oil and was investigated for its ability to degrade varying concentration of crude oil (1.0, 3.0, 5.0 and 7.5 %) and produce peroxidase during the biodegradation period. Increase in biomass enhanced degradation efficiency above 80 % after 10 days for all concentration of crude oil studied. Peroxidase production increased maximally during the log phase of growth with a maximum production of (3.01 U/L) on day 10 for 3% crude oil and (2.08 U/L) for 5% crude oil medium on day 12. These remarkable properties displayed by Streptomyces albus in this study showed how tolerant and efficient this actinobacterial isolate was toward varying concentration of crude oil vis-à-vis the production of peroxidase.

Exploration of secondary metabolites secreted by new Actinobacteria taxa isolated from unexplored areas, can increase the possibility to obtain new compounds which can be developed into new drugs for the treatment of serious diseases such as hepatitis C. In this context, one actinobacterial strain, CG3, has been selected based on the results of polyphasic characterization, which indicate that it represents a new putative species within the genus Nocardiopsis. Two fractions (F2 and F3), prepared from the culture of strain CG3 in soybean medium, exhibited a pronounced antiviral activity against the HCV strain Luc-Jc1. LC-HRESIMS analysis showed different bioactive compounds in both active fractions (F2 and F3), including five polyenic macrolactams (kenalactams A-E), three isoflavone metabolites, along with mitomycin C and one p-phenyl derivative. Furthermore, feeding with 1% of methionine, lysine or alanine as a unique nitrogen source, induced the production of three novel kenalactam derivatives.

The diversity of cultural Actinobacteria in two types of Algerian Sahara environments, including saline environments and date palms rhizosphere, was investigated. In this study, a total of 40 strains of actinomycetes was isolated from different soil samples, using a rehydration and centrifugation method. Molecular identification, based on 16S rRNA gene sequence analysis, revealed that these isolates were affiliated to six clusters corresponding to eight genera, including Streptomyces, Nocardiopsis, Saccharopolyspora, Actinomadura, Actinocorallia, Micromonospora, Couchioplanes, and Planomonospora. A taxonomic analysis, based on the morphological, physiological, biochemical, and molecular investigation, of selected strains, which belong to the rare Actinobacteria, was undertaken. Four strains (CG3, A111, A93, and A79) were found to form distinct phyletic lines and represent new actinobacterial taxa. An assessment of antimicrobial proprieties of the 40 obtained actinomycetes strains, showed moderate to strong antimicrobial activities against fungi and bacteria. This study demonstrated the richness of Algerian Sahara with rare Actinobacteria, which can provide novel bioactive metabolites, to solving some of the most challenging problems of the day, such as multi-drug resistance.

Cellulases are important industrial enzymes for sustainable production of biofuel as they convert the cellulose into fermentable sugars. Cellulases from Streptomyces spp. like S. ruber, S. lividans and S. rutgersensis are highly thermostable [8]. These enzymes are mostly used as a supplement in detergents, textile, animal additives and paper and pulp industry [22,23]. Some members of genera Thermobifida and Micromonospora also produce cellulases that exhibit industrial

Actinomycetes are the most profitable and biotechnologically valued prokaryotes representing the genera consisting of Streptomyces, Arthrobacter, Actinomyces, Cornyebacterium, Micrococcus, Micromonospora and other diverse species of microorganisms. Actinomycetes represent a group of one of the most powerful secondary metabolite producers which possess a wide range of biological activities. Streptomyces, an important genus under actinomycetes, alone serves as the huge producer of a number of biologically active molecules. This genus possesses a huge potential of synthesizing various different and novel active metabolites. Due to the gradual reduction of the chances of isolation of novel compounds within Streptomyces coming from terrestrial environs resulting in the increase of resistant pathogenic microorganisms, marine actinomycetesmay form a platform for novel drug synthesis, which in-turn may form an extraordinary tool for combating a wide range of resistant microbes. The role of ...

A halotolerant 4-nitrophenol (4-NP) degrading bacterial strain designated as BUPNP2 was isolated by enrichment culture technique from the rhizospheric soil of rice plants (Oryzae sativa) of an agricultural field located in Memari within Burdwan district of West Bengal, India. It was identified as a member of genus Bacillus by 16S rRNA gene based molecular phylogenetic approach. The strain was capable of degrading 4-NP (0.3 mM) as sole source of carbon through 4nitrocatechol (4-NC) as intermediate. The strain also tolerated up to 12 % NaCl (w/v). The degradation capacity of 4-NP was enhanced by this strain up to 0.6 mM in presence of cellulose, starch and glucose. The strain could tolerate several heavy metals such as cadmium, chromium, iron, lead, nickel and zinc and it was degrading 4-NP in presence of each of these heavy metals. Glucose, starch and cellulose also enhanced 4-NP degradation capacity of the strain even in presence of each of these heavy metals. The strain BUPNP2 also possessed important plant growth promoting (PGP) traits such as production of siderophore, indole acetic acid (IAA), ammonia; phosphate solubilization along with protease, lipase, amylase and cellulase activities. Thus, the halotolerant strain BUPNP2 has biotechnological potential and can be utilized for bioremediation of heavy metal infested 4-NP contaminated agricultural soil (common in industrial belt) where it might also help in plant growth promotion.

This review conceptualizes about the actinomycetes and its contribution to human health by playing a key role as bioactive secondary metabolites, such as enzymes, antibiotics and pigments, leading to their diverse applications and use in various industries. These searches have been uncommonly successful, and around 66% of naturally happening antibiotics, including many medically important, have been isolated from actinomycetes. The speedy occurrence of antimicrobial resistance among pathogens has led to a renewed interest to search for novel antimicrobial agents, but these antibiotics are not enough for the treatment of all diseases because there is a berserk requirement for a novel actinomycetes to combat against the antibiotic-resistant strains of pathogenic microorganisms, which are quickly expanding bit by bit. Actinomycetes are the important providers to the pharmaceutical and other industries and are well known for their capacity to produce secondary metabolites many of which are active against pathogenic microorganisms.

Actinomycetes are the source of many secondary metabolites, enzymes, and antimicrobials that have various applications. Microorganism proliferation is aided in practice by mediated mutations utilizing UV and monochromatic laser radiation. This study aimed to evaluate the photostimulatory effect of UV and laser light on the lipase, amylase and antimicrobial productivity of three actinomycetes' strains from genera: Micromonospora, Pseudonocardia, and Nocardiopsis. The strains were exposed to UV (300-400 nm) and monochromatic laser (632.8 nm) radiations for 10 and 20 minutes. The influence of radiations on the actinomycetes' growth, pigment production, enzymatic and antimicrobial activity was evaluated after incubation at 28 ±2 • C for 7 days. Two reference bacterial strains Escherichia coli NCMB 11943 and Staphylococcus aureus NCMB 6571, and one clinical yeast strain Candida albicans, were used for antibacterial assessment, compared to five commercial antibiotics. The results showed better radiation response of the selected actinomycetes strains to the monochromatic laser. Both Pseudonocardia and Micromonospora have exhibited significant increase in pigmentation with laser exposure. In contrast, Nocardiopsis has shown reduction in pigment production. The UV and Laser radiations have almost doubled the amylase enzyme activity in Pseudonocardia and Micromonospora strains, while not affecting lipase production. On the other hand, the crude metabolites from the Micromonospora sp. strain exhibited a highly promising inhibitory effect against E. coli (NCMB11943) when compared with five commercially available antibiotics. The laser irradiation for 10 min has almost doubled the inhibitory zone of Micromonospora metabolites against S. aureus (from 0.65 to 1.2 cm) and C. albicans (from 0.7 to 1.3 cm). In conclusion, the results of our research recommend using monochromatic laser radiation to enhance the production of amylase and antimicrobial metabolites from Pseudonocardia and Micromonospora, respectively.

Background: Azo dyes are xenobiotic compounds that have bioaccumulated in the environment due to escalated industrial development. These are hazardous in nature, possessing carcinogenic and mutagenic effects on human beings. Objectives: The perspective of the present study was to isolate and to determine azo dye (Reactive Orange-16) degrading potential of marine actinobacteria isolated from sediment samples of Port Blair, India. Material and Methods: Actinobacteria with dye decolorization potential were isolated from sea sediment samples. The actinobacterial isolate with the highest dye decolorizing percentage was identified with the help of phenotypic, biochemical and molecular studies. The different physico-chemical parameters for dye decolorization were also optimized. The nature of decolorization by the potent isolate was determined with the help of High Performance Liquid chromatography (HPLC) and Fourier Transformed Infrared spectroscopy (FTIR) techniques. Further the toxicity of RO-16 decolorized products was investigated with the help of phytotoxcity assay. Results: Out of six actinobacterial isolates, VITVAMB 1 possessed the most efficient RO-16 decolorization property. It decolorized 85.6% of RO-16 (250 mg L-1) within 24hrs. Isolate VITVAMB 1 was identified to be Nocardiopsis sp. Maximum dye decolorization occurred at pH 8, temperature 35°C, 3% salt concentration and a dye concentration of 50 mg L-1. Conclusions: The nature of decolorization by Nocardiopsis sp. was biodegradation. Additionally, the degraded dye metabolites were found to be less toxic than pure dye. The high decolorization potential of VITVAMB 1 and the low toxicity of its degradation products make it a prospective dye removal system. The marine origin of VITVAMB 1 also makes it an attractive source for novel azo dye reducing enzymes.

Actinobacteria, which share the characteristics of both bacteria and fungi, are widely distributed in both terrestrial and aquatic ecosystems, mainly in soil, where they play an essential role in recycling refractory biomaterials by decomposing complex mixtures of polymers in dead plants and animals and fungal materials. They are considered as the biotechnologically valuable bacteria that are exploited for its secondary metabolite production. Approximately, 10,000 bioactive metabolites are produced by Actinobacteria, which is 45% of all bioactive microbial metabolites discovered. Especially Streptomyces species produce industrially important microorganisms as they are a rich source of several useful bioactive natural products with potential applications. Though it has various applications, some Actinobacteria have its own negative effect against plants, animals, and humans. On this context, this chapter summarizes the general characteristics of Actinobacteria, its habitat, systematic classification, various biotechnological applications, and negative impact on plants and animals.

Background: Azo dyes are xenobiotic compounds that have bioaccumulated in the environment due to escalated industrial development. These are hazardous in nature, possessing carcinogenic and mutagenic effects on human beings. Objectives: The perspective of the present study was to isolate and to determine azo dye (Reactive Orange-16) degrading potential of marine actinobacteria isolated from sediment samples of Port Blair, India. Material and Methods: Actinobacteria with dye decolorization potential were isolated from sea sediment samples. The actinobacterial isolate with the highest dye decolorizing percentage was identified with the help of phenotypic, biochemical and molecular studies. The different physico-chemical parameters for dye decolorization were also optimized. The nature of decolorization by the potent isolate was determined with the help of High Performance Liquid chromatography (HPLC) and Fourier Transformed Infrared spectroscopy (FTIR) techniques. Further the toxicity of RO-16 decolorized products was investigated with the help of phytotoxcity assay. Results: Out of six actinobacterial isolates, VITVAMB 1 possessed the most efficient RO-16 decolorization property. It decolorized 85.6% of RO-16 (250 mg L-1) within 24hrs. Isolate VITVAMB 1 was identified to be Nocardiopsis sp. Maximum dye decolorization occurred at pH 8, temperature 35°C, 3% salt concentration and a dye concentration of 50 mg L-1. Conclusions: The nature of decolorization by Nocardiopsis sp. was biodegradation. Additionally, the degraded dye metabolites were found to be less toxic than pure dye. The high decolorization potential of VITVAMB 1 and the low toxicity of its degradation products make it a prospective dye removal system. The marine origin of VITVAMB 1 also makes it an attractive source for novel azo dye reducing enzymes.

Background: Azo dyes are xenobiotic compounds that have bioaccumulated in the environment due to escalated industrial development. These are hazardous in nature, possessing carcinogenic and mutagenic effects on human beings. Objectives: The perspective of the present study was to isolate and to determine azo dye (Reactive Orange-16) degrading potential of marine actinobacteria isolated from sediment samples of Port Blair, India. Material and Methods: Actinobacteria with dye decolorization potential were isolated from sea sediment samples. The actinobacterial isolate with the highest dye decolorizing percentage was identified with the help of phenotypic, biochemical and molecular studies. The different physico-chemical parameters for dye decolorization were also optimized. The nature of decolorization by the potent isolate was determined with the help of High Performance Liquid chromatography (HPLC) and Fourier Transformed Infrared spectroscopy (FTIR) techniques. Further the toxicity of RO-16 decolorized products was investigated with the help of phytotoxcity assay. Results: Out of six actinobacterial isolates, VITVAMB 1 possessed the most efficient RO-16 decolorization property. It decolorized 85.6% of RO-16 (250 mg L-1) within 24hrs. Isolate VITVAMB 1 was identified to be Nocardiopsis sp. Maximum dye decolorization occurred at pH 8, temperature 35°C, 3% salt concentration and a dye concentration of 50 mg L-1. Conclusions: The nature of decolorization by Nocardiopsis sp. was biodegradation. Additionally, the degraded dye metabolites were found to be less toxic than pure dye. The high decolorization potential of VITVAMB 1 and the low toxicity of its degradation products make it a prospective dye removal system. The marine origin of VITVAMB 1 also makes it an attractive source for novel azo dye reducing enzymes.

The disadvantages associated with conventional treatment of crude oil pollution have led to the development of alternative, economical and reliable biological treatments. In this study, six actinobacterial isolates were obtained from 120cm soil depth of a selected crude oil contaminated site in the Niger Delta region of Nigeria. Streptomyces albus was selected from the six isolates based on its comparative ability to growth on crude oil and was investigated for its ability to degrade varying concentration of crude oil (1.0, 3.0, 5.0 and 7.5 %) and produce peroxidase during the biodegradation period. Increase in biomass enhanced degradation efficiency above 80 % after 10 days for all concentration of crude oil studied. Peroxidase production increased maximally during the log phase of growth with a maximum production of (3.01 U/L) on day 10 for 3% crude oil and (2.08 U/L) for 5% crude oil medium on day 12. These remarkable properties displayed by Streptomyces albus in this study showed how tolerant and efficient this actinobacterial isolate was toward varying concentration of crude oil vis-à-vis the production of peroxidase.

The main objective of this study was using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for assembling of DSM (German Collection of Microorganisms) Streptomyces spectral database and identification of wild Streptomyces cultures, which were clustered by MALDI-TOF Biotyper OC software as well as for teracycline detection by observing of obtained spectra using flexAnalysis software. Production of tetracycline was confirmed by thin-layer chromatography. Presence of tetracycline mass spectrum was verified by several tetracycline producers (Streptomyces aureofaciens LMG 5968, S. aureofaciens 84/25, and S. aureofaciens BMK) and by pure tetracycline mass. Our results showed that it is possible to use MALDI-TOF MS for identification of tetracycline producers within Streptomyces genera by several easy steps. The purpose of this study was to establish cheap and quick detection of tetracycline producers.

In this study, we redesigned and evaluated primers for the class Actinobacteria. In silico testing showed that the primers had a perfect match with 82% of genera in the class Actinobacteria , representing a 26-213% improvement over previously reported primers. Only 4% of genera that displayed mismatches did so in the terminal three bases of the 3 ¢ ¢ ¢ ¢ end, which is most critical for polymerase chain reaction success. The primers, designated S-C-Act-0235-aS -20 and S-C-Act-0878-a-A-19, amplified an ª ª ª ª 640 bp stretch of the 16S rRNA gene from all actinobacteria tested (except Rubrobacter radiotolerans) up to an annealing temperature of 72 ∞ ∞ ∞ ∞ C. An Actinobacteria Amplification Resource (http://microbe2.ncl.ac.uk/MMB/AAR.htm) was generated to provide a visual guide to aid the amplification of actinobacterial 16S rDNA. Application of the primers to DNA extracted from marine and terrestrial samples revealed the presence of actinobacteria that have not been described previously. The use of 16S rDNA similarity and DNA-DNA pairing correlations showed that almost every actinomycete clone represented either a new species or a novel genus. The results of this study reinforce the proposition that current culture-based techniques drastically underestimate the diversity of Actinobacteria in the environment and highlight the need to evaluate taxonspecific primers regularly in line with improvements in databases holding 16S rDNA sequences.

The objectives of this study were to assess actinobacterial diversity in five Moroccan extreme habitats and to evaluate their plant growth-promoting (PGP) activities. The soil samples were collected from different locations, including soils contaminated with heavy metals, from a high altitude site, from the desert, and from a marine environment. In total, 23 actinobacteria were isolated, 8 from Merzouga sand soil; 5 from Cannabis sativa rhizospheric soil; 5 from Toubkal mountain; 4 from a Draa sfar mining site; and 1 from marine soil. Based on their genotypic classification using 16S rRNA gene sequences, 19 of all belonged to the genus Streptomyces (82%) while the rest are the members of the genera Nocardioides (4.5%), Saccharomonospora (4.5%), Actinomadura (4.5%), and Prauserella (4.5%). Isolates Streptomyces sp. TNC-1 and Streptomyces sp. MNC-1 showed the highest level of phosphorus solubilization activity with 12.39 and 8.56 mg/mL, respectively. All 23 isolates were able to solub...

Actinobacteria are of special biotechnological interest since they are known to produce chemically diverse compounds with a wide range of biological activity. This distinct clade of Gram-positve bacteria include some of the key antibiotic producers and are also sources of several bioactive compounds, established commercially. The class Actinobacteria holds some of the resilient species, capable of growing in extreme, hostile and polluted environments. Their adaptation has been the outcome of several chemical entities which are answers to a number of medicinal and industrial questions of today. In India, actinobacterial research in both marine and terrestrial ecosystems has prospered significantly in past few decades. This valuable class contains large number of genera and demands more attention for exploration. Though substantial work in this field has been carried out, the diversity from the extreme environments in the Indian Peninsula remain unexplored. Marine actinobacterial rese...

Actinobacteria are the leading producers of antibiotic, cytotoxic, and other biologically active compounds [1-3]. The marine world has been for several decades a rich source of these producers [4-6]. In continuation of the search for biologically active compounds in actinobacteria of the Okhotsk Sea, we determined the composition of free fatty acids from Streptomyces sp. KMM 7210 [7] that were studied previously by us, and Nocardiopsis umidischolae KMM 7036. Actinobacterium Streptomyces sp. KMM 7210 was isolated from sediment collected at a depth of 3 m (Troits Bay, Poseta Gulf, Sea of Japan). The strain was cultivated with rocking for 5 d at 22°C in Ehrlenmeyer flasks (300-mL), each of which contained potato starch (1.0 g), peptone (0.2 g), yeast extract (0.2 g), CaCO 3 (0.1 g), and distilled water and seawater (50 mL each) at pH 7.7. The culture medium was worked up with EtOAc and evaporated in vacuo. Actinobacterium Nocardiopsis umidischolae KMM 7036 was isolated from a sponge Mycale sp. collected at a depth of 606 m (Deryugin Bank, Sea of Okhotsk). The strain was cultivated for 28 d at 28°C in 40 Petri dishes, each of which contained agar (0.4 g), FeSO 4 (0.00125 g), MgSO 4 (0.0025 g), filtered millet broth (15 mL), and seawater (10 mL) at pH 7.5. The millet broth was prepared from millet (100 g) and distilled H 2 O (600 mL). The biomass was worked up with EtOAc and evaporated in vacuo. Total fractions of fatty acids were obtained by chromatography of EtOAc extracts over silica gel using hexane:EtOAc (0o10%). Fatty acids as methyl esters were analyzed by GC [HP-5SM column (0.2 mm u 30 m); Agilent 6850, Germany]. The temperature program was injector 270°C, 100°C (1 min), 10°C/min, 270°C (20 min), detector 300°C (He carrier gas). GC-MC of fatty-acid methyl esters was carried out in the same mode on an HP GC 6890 spectrometer with an HP-5 ms column (30 m u 250 mm u 0.25 Pm) with 5% phenylmethylsiloxane (MSD5973, Hewlett-Packard, USA) (He carrier gas). Compounds were identified by comparison of experimental mass spectra with those of known compounds using the NIST98 database. Table 1 presents data for the fatty-acid compositions of the bacteria. According to the results (Table 1), both strains produced saturated, unsaturated, and branched acids. The fraction of unsaturated acids was greater than that of saturated. N. umidischolae contained a high percent of palmitic acid (18.9%) whereas its content in the Streptomyces sp. was 4.0% with the fraction of stearic acid in it reaching 13.9%. High contents of palmitic (16:0) and stearic (18:0) acids are characteristic of actinobacteria [8-10], in particular actinobacteria of the genera Streptomyces [10] and Nocardiopsis [9, 11]. N. umidischolae produced tuberculostearic acid (10-methyl-C 18:0), the presence of which is characteristic of all representative of this genus [9, 11-13]. Actinobacteria are known to produce fatty acids (saturated, unsaturated, branched) with chain lengths in the range C 10-C 18 [11-14]. Our results agreed with those in the literature. The fatty-acid composition of N. umidischolae isolated from the marine world was studied for the first time.

Moonmilk are cave carbonate deposits that host a rich microbiome, including antibiotic-producing Actinobacteria, making these speleothems appealing for bioprospecting. Here, we investigated the taxonomic profile of the actinobacterial community of three moonmilk deposits of the cave &quot;Grotte des Collemboles&quot; via high-throughput sequencing of 16S rRNA amplicons. Actinobacteria was the most common phylum after Proteobacteria, ranging from 9% to 23% of the total bacterial population. Next to actinobacterial operational taxonomic units (OTUs) attributed to uncultured organisms at the genus level (~44%), we identified 47 actinobacterial genera with (4 OTUs, 17%) and (9 OTUs, ~16%) as the most abundant in terms of the absolute number of sequences. Streptomycetes presented the highest diversity (19 OTUs, 3%), with most of the OTUs unlinked to the culturable strains that were previously isolated from the same deposits. Furthermore, 43% of the OTUs were shared between the three stud...

The ocean is considered to be an immense reservoir of biological and microbial diversity on the planet. In marine biospheres, microbial communities are ecologically significant as intermediaries of energy. By decomposing the dead as well as decaying organic matter with the assistance of microbial communities, it plays an indispensable role in the nutrient regeneration cycles of marine ecosystems. Marine environments associated with microorganisms such as bacteria, fungi, and bacterial virus have renowned potential to produce novel bioactive natural products and chemically diverse secondary metabolites like antibiotics, antifungal, antiviral, antitumor, anticancer, and also different hydrolyzing enzymes, namely, protease, lipase, amylase, chitinase, etc. Hence, the bioprospecting for these compounds is of greater importance. Numerous effective and efficient applications of marine microbial metabolites contribute to the fields of pharmaceuticals, biotechnological, agricultural, cosmet...

Phosphorous that sustains marine life become inaccessible as most of them become insoluble due to the formation of complexes with cations and thus the availability of soluble phosphorous decreases to a greater extent. There are reports envisaging marine microbes to play a crucial role in solubilizing these phosphates by the excretion of organic acids, phosphatase and phytase enzymes. In spite of the action of these microbial products, an enormous quantity of insoluble phosphate precipitates to the ocean sediments thus posing a hindrance to the phosphorous biogeochemical cycle. It has been previously evidenced that local ecosystem e.g. coral reefs accomplish a faster cycling of insoluble phosphates. Thus the results of the present study put forth a possible hypothesis that sponge associated actinomycetes and on the whole microbial community of the coral reefs can play a potential role in solubilizing the phosphates and thus increasing the efficiency of phosphorous cycle. This present work opens a new door step for the in vivo study that can be focused on further possible mechanism of phosphate accumulation and solubilization by bacterial communities associated with benthic invertebrates.

A halotolerant 4-nitrophenol (4-NP) degrading bacterial strain designated as BUPNP2 was isolated by enrichment culture technique from the rhizospheric soil of rice plants (Oryzae sativa) of an agricultural field located in Memari within Burdwan district of West Bengal, India. It was identified as a member of genus Bacillus by 16S rRNA gene based molecular phylogenetic approach. The strain was capable of degrading 4-NP (0.3 mM) as sole source of carbon through 4nitrocatechol (4-NC) as intermediate. The strain also tolerated up to 12 % NaCl (w/v). The degradation capacity of 4-NP was enhanced by this strain up to 0.6 mM in presence of cellulose, starch and glucose. The strain could tolerate several heavy metals such as cadmium, chromium, iron, lead, nickel and zinc and it was degrading 4-NP in presence of each of these heavy metals. Glucose, starch and cellulose also enhanced 4-NP degradation capacity of the strain even in presence of each of these heavy metals. The strain BUPNP2 also possessed important plant growth promoting (PGP) traits such as production of siderophore, indole acetic acid (IAA), ammonia; phosphate solubilization along with protease, lipase, amylase and cellulase activities. Thus, the halotolerant strain BUPNP2 has biotechnological potential and can be utilized for bioremediation of heavy metal infested 4-NP contaminated agricultural soil (common in industrial belt) where it might also help in plant growth promotion.

Emergence of multidrug resistant bacteria has made the search for novel bioactive compounds from natural and unexplored habitats a necessity. Actinobacteria have important bioactive substances. The present study investigated antimicrobial activity of Actinobacteria isolated from soil samples of Egypt. One hundred samples were collected from agricultural farming soil of different governorates. Twelve isolates have produced activity against the tested microorganisms (S. aureus, Bacillus cereus, E. coli, K. pneumoniae, P. aeruginosa, S. Typhi, C. albicans, A. niger and A. flavus). By VITEK 2 system version: 07.01 the 12 isolates were identified as Kocuria kristinae, Kocuria rosea, Streptomyces griseus, Streptomyces flaveolus and Actinobacteria. Using ethyl acetate extraction method the isolates culture's supernatants were tested by diffusion method against indicator microorganisms. These results indicate that Actinobacteria isolated from Egypt farms could be sources of antimicrobial bioactive substances.

The present study reveals the plant growth-promoting (PGP) potentials and characterizes the antifungal metabolites of Kutzneria sp. strain TSII isolated from mangrove sediment soil through in vitro and in silico studies. In this study, Kutzneria sp. strain TSII was screened for PGP activities and the antifungal activities against Pithomyces atro-olivaceous, a leaf spot-associated pathogen in groundnut plants. The ethyl acetate extract of Kutzneria sp. strain TSII was purified using column chromatography, and the presence of various antimicrobial compounds was studied by gas chromatography-mass spectrometry (GC-MS) analysis. In silico modeling and docking were carried out to evaluate the antifungal potent of bioactive compound. Kutzneria sp. strain TSII produced proteases, phosphatases, ammonia, siderophores, cellulases, indole acetic acid (IAA), lipases, and amylases, indicating its ability to enhance the growth of plants. The ethyl acetate extract of Kutzneria sp strain TSII was found to be a potent inhibitor of fungal mycelial growth in the potato dextrose agar (PDA) plates. The GC-MS spectral study showed 24 antimicrobial compounds belonging to five chemical groups: phenolics, phthalates, fatty acid methyl esters (FAME), spiro, and fatty alcohols. In silico docking studies showed that phenol, 2,4-bis(1,1dimethylethyl)-effectively attaches with the active site of mitochondrial F 1 F 0 Adenosine triphosphate synthase enzymes of Pithomyces atro-olivaceous. Hence, it is clear that these antifungal compounds shall be formulated shortly to treat many plant fungal diseases in an eco-friendly manner.

Aim: Alzheimer's disease (AD) is the most common cause of dementia. The acetylcholinesterase (AChE) inhibitors are the most viable therapeutic target for its symptomatic treatment. The present study was aimed at exploring anti-AChE metabolite producing marine Actinobacteria. Methods and Results: Out of 220 isolates, 34 Actinobacteria extracts were tested for the presence of AChE inhibitors. The obtained results showed that bacterial strain UTMC 1334, inhibited AChE activity in a dosedependent manner (IC 50 = 0.36 ± 0.019 mg ml-1). Based on anti-oxidant and cytotoxicity studies, the most potent extract was able to scavenge DPPH radicals with an IC 50 value of 45.67 μg ml-1 with the least cytotoxicity. The GC-MS analysis demonstrated the mentioned activities could be related to pyrrole-derived compounds as found predominant constituents in the extract. The most active extract belonged to the strain that shows 99.41% similarity with Streptomyces lateritius based on 16S rRNA gene sequencing. Conclusions: Our results show anti-acetylcholinesterase activity is prevalent in marine Actinobacteria, and even in rather comparable prevalence with the antibiotics. Significance and Impact of the Study: This study highlights that exploring new lead anti-acetylcholinesterase compounds may result in discovering novel adjuvant candidates with potency in the treatment of cognitive diseases such as AD.

Red biopigments produced by actinobacteria represent an important substitute in the food industry to synthetic pigments, which can cause harmful effects on human health and the environment. In this study, pigment production by actinobacteria strain UFPEDA 3422, identified by polyphasic taxonomy, was investigated. The cultivation parameters related to growth and pigment production were assayed in solid culture media and submerged fermentation. The red cell pigment was extracted with ethyl acetate and analyzed in a UV-Vis spectrophotometer with maximum production of the pigment (34.9 AU540 nm) in Hickey-Tresner (HT) medium for 48 hours at 37 ºC. The maximum biomass concentration (33.4 g/L) was obtained after 96 hours. Polyphasic taxonomy confirms 97.4% similarity of strain UFPEDA 3422 with the Amycolatopsis, a rare genus able to produce pigments on different substrates. In addition, the microorganism has tolerance to temperature variations, pH fluctuations and concentrations of 5% NaC...

This study investigated the coproduction of alkaline amylase and lipopeptides by Bacillus methylotrophicus DCS1 strain, as well as their biochemical characterisation. The best production of both amylase and biosurfactant was obtained when potato starch (10 g/L) and glutamic acid (5 g/L) were used as carbon and nitrogen sources, respectively. The bacterial strain was incubated for 48 h at 25°C and 150 rpm. This strain produced a unique amylase as showed by zymography technique. The optima pH and temperature were 60-65°C and 8.0, respectively. Amylase activity was partially inhibited by EDTA (5 mM). The main hydrolysis products of potato starch were maltose and maltotriose. The alkaline amylase showed excellent stability and compatibility with various solid and liquid detergents. Furthermore, the biosurfactant, produced simultaneously with alkaline amylase, demonstrated high stability at different ranges of salinity, pH, and temperature. Considering its promising properties, B. methylotrophicus DCS1 crude extract containing both biosurfactants and amylase activity may be considered as a potential candidate for future use in detergent processing industries and environmental remediation processes. Keywords a-Amylase Á Bacillus methylotrophicus Á Biosurfactant Á Biochemical characterization Á Detergent 123 Biodegradation

Background: Endophytic non-streptomycetes group of actinomycetes from Hibiscus rosasinensis leaves were screened for biosurfactant, polythene, plastic, and diesel biodegradation activities. Biosurfactant activity was evaluated by hemolysis, drop-collapsing test, lipase production, oil-spreading technique, bacterial adhesion to hydrocarbon (BATH) assay, penetration assay, and emulsification assay. Similarly, polythene, plastic, and diesel biodegradation activity were also carried out. Findings: Among the five non-streptomycetes isolates, only one newly found actinomycete isolate named as A9 exhibited significant biosurfactant and biodegradation activity. Based on Bergey's manual of systematic bacteriology, the strain A9 was similar to Nocardiopsis sp. Molecular characterization and phylogenetic analysis support the classification of the isolate as a new strain which was named as Nocardiopsis sp.mrinalini9. The isolate was closely related to the type strain of Nocardiopsis synnemataformans sharing a 16S rRNA gene sequence similarity of 99%. The partial 16S rRNA sequence of the isolate (1061 bp) was deposited in Genebank under the accession number KF909126. Still, DNA-DNA hybridizations, phenotypic comparisons, and chemotaxonomic analysis need to be performed to confirm its novelty. Conclusion: It is evident from the study that rare endphytes associated with medicinal plants has got excellent hydrocarbon biodegradation capacity.