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Biosurfactant from Streptomyces zaomyceticus HUS20 isolated from the Indian Himalayan Region (IHR) and its antibacterial activity
(2025-07-01)
Kishorekumar, A.
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Radhakrishnan, M.
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Manigundan, K.
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Ranjani, S.
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Thenmozhli, G. S.
Actinobacteria, which are known to synthesize bioactive molecules with significant industrial and medicinal applications. In order to assess the possibility for producing biosurfactant (BS), this study identified culturable actinobacteria from the high-altitude soils of Drama Valley, Dugtu Village in the Indian Himalayan Region (IHR). Actinobacteria were isolated from pre-treated soil samples using nutrient agar, starch casein nitrate agar, and actinomycetes isolation agar, which were enhanced with 1% crude oil. Using the haemolytic assay, oil displacement test, emulsification activity, drop collapse assay, and penetration assay, morphologically different colonies were proved for the production of BS. In this study, a promising biosurfactant-producing strain, strain HUS20 showed considerable emulsification index (65%) and a 30 mm zone in the oil displacement test. Using 16S rRNA sequencing, the strain HUS20 was shown to be 100% identical to Streptomyces zaomyceticus (GenBank accession: OQ996835.1). in HR LC MS analysis, the crude biosurfactant extract showed the presence of more than 164 metabolites. Additionally, the crude biosurfactant demonstrated strong antibacterial action against foodborne pathogens, with Bacillus cereus showing the greatest suppression (24 mm zone at 100 mg/ml). The potential of actinobacteria from harsh Himalayan habitats as a useful resource for the synthesis of biosurfactants is highlighted by this work. Streptomyces zaomyceticus HUS20 is found to be promising strain for isolation of potential biosurfactant molecule.
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Harnessing microbial biosurfactant for agricultural applications
(2024-01-01)
Eshwarnath, V. S.
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Thyagarajan, R.
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Kishorekumar, A.
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Gopikrishnan, V.
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Radhakrishnan, M.
Biosurfactant refers to surface-acting substances that can enhance surface-surface interactions by generating micelles that are derived from natural sources including plants, microorganisms, and animals. Biosurfactants are a structurally diverse group of secondary metabolites with lots of potential to serve mankind. The structural and compositional diversity of biosurfactants is unambiguously substrate-dependent. Microbial surfactants are environment-friendly alternatives to synthetic surfactants. Biosurfactants are surface-active agents produced by microorganisms that have higher efficiency and stability, lower toxicity and higher biocompatibility and biodegradability than chemical surfactants. The differences between biosurfactant production can be attributed to the different compositions of the hydrolyzates.
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Isolation and screening of fish gut actinomycetes for antibacterial activity against Uropathogenic Escherichia coli
(2023-09-01)
Jisha, K.
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Gayathri, G.
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Gopikrishnan, V.
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Vareeket, R.
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Prabha, T. R.
Actinobacteria are among the most studied prokaryotes due to their propensity to create microbial bioactive compounds. Actinobacterial members can be found in a wide variety of aquatic and terrestrial settings, incorporating marine habitats. Actinomycetes isolated from the marine environment are gaining popularity due to their diverse structures and unique biological properties of the secondary metabolic products. The research was investigated the antibacterial properties of actinobacteria associated with gut of marine fish against human pathogen. Approximately 20 morphologically distinct strains obtained from Engraulis sp. (anchovy fish) and Trachurus trachurus (horse mackerel) were proved for antibacterial efficacy against Extended spectrum beta-lactamase (ESBL) producing uropathogenic Escherichia coli (UPEC). The actinobacterial strain HM7 expressed antibacterial effect against UPEC.
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Fish gut microbiota: a source of novel metabolites – A review article
(2023-03-01)
Jisha, K.
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Gayathri, G.
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Gopikrishnan, V.
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Song, J. J.
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Soytong, K.
Similar to human beings, fish harbor microorganisms in their gastrointestinal tract (GIT). Fishes are diverse groups of gut microbiota, including protists, fungi, yeasts, viruses, bacteria, and archaea. In addition to serving as a barrier against infections, these microbes that inhabit the gastrointestinal tract of fish play a role in nutrition, physiology, immunity, and life span. All fish have gut microbiota; however, the makeup of these communities varies depending on the fish's life stages, the habitat they live in, their nutrition, the seasons, their trophic level, etc. For both recreational and commercial fisheries, it is crucial to comprehend the bacterial make-up of fish microbiomes. The gut microbiota aids in the development of methods for modifying the gut microbiota of the target fish species to enhance aquaculture quality. These gut microbes are an invaluable, essential source of novel, promising bioactive compounds with significant biological activity. The natural product secondary metabolites from specific strains of Chaetomium spp. may develop to be biomedicine for sustainable protection. This review provides a comprehensive knowledge of the composition of the gut microbiota of fish, their development, changes in the living environment, their modification, and their applications.
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Exploration of earthwormcast associated actinobacteria for plant growth promoting properties
(2023-01-01)
Ashok Kumar, S.
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Karthiga, P.
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Rajalakshmi, G.
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Gopikrishnan, V.
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Radhakrishnan, M.
Due to their wide varieties of chemicals with a variety of biological actions, earthworms, cast, and gut are potential sources of significant biotechnological interest. The finding new microorganisms in peculiar and uncharted habitats were investigated. Actinobacteria are exceptional makers of secondary metabolites and have a wide range of bioactive substances of economic significance. In the current investigation, actinobacteria from earthworm casting were isolated for their potential antibacterial capabilities. Earthworm cast from the Kanchipuram agricultural area had a total of 12 actinobacterial colonies. Human and plant pathogens such as Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa and Ralstonia solanacearum were tested against each actinobacterial cultures. The selected potential culture was examined for the presence of Indole Acetic Acid (IAA), Phosphate (P) solubilization, extracellular enzymes such as cellulase and amylase. For the promising active trains, optimization, characterization and taxonomy were carried out. Colonies with various morphologies were separated and subcultured for testing their activities. Six of the twelve isolates proved positive for antibacterial activity against one or more pathogens. Of the six isolates tested, strain EWCA 21 was chosen for further screening because it had the greatest effectiveness against tested pathogens. IAA, Phosphate (P) solubilization, and extracellular enzyme activities such amylase and cellulase were demonstrated in EWCA21. Carbon and nitrogen sources expressed an increase in activity and output during optimization. The putative strain was determined to be Streptomyces based on phenotypic analysis. The study concluded that the strain EWCA21 would be developed as a crucial resource for biofertilizer applications.
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A novel of bioprospecting of earthworm cast associated actinobacteria for its antimicrobial properties-Short communication
(2021-03-01)
Gopikrishnan, V.
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Radhakrishnan, M.
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Joseph, J.
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Abirami, B.
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Manigundan, K.
Among bacteria, the actinobacteria are the most significant source of bioactive compounds and many industrially important by products in use today. The present study designed to isolate the actinobacteria from earthworm cast for its antimicrobial properties. Totally 56 actinobacterial colonies were isolated from earthworm cast of Kanchipuram agricultural area. Of which, 36 morphologically different colonies were isolated and identified which mostly belong to Streptomyces. In antimicrobial activity, among 36 isolates, 12 were showed antimicrobial activity against one or more tested human pathogens eg Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. So, the study revealed earthworm cast associated actinobacteria can be recorded as an imperative resource for bio-prospecting that could produce novel bioactive metabolites.
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Identification of biostimulant and microbicide compounds from Streptomyces sp. UC1A-3 for plant growth promotion and disease control
(2020-09-01)
Manigundan, K.
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Joseph, J.
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Ayswarya, S.
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Vignesh, A.
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Vijayalakshmi, G.
The plant growth promotion and antagonistic potential of Streptomyces against phytopathogens was assessed. Total fourteen Streptomyces strains were derived from rhizosphere soil of Capsicum annum (Chilli) from the agricultural fields in Udhagamandalam, Nilgiris, Tamil Nadu, India. All strains were evaluated for plant growth promoting in vitro e.g. production of indole acetic acid, ammonia, siderophores, chitinase, cellulase, protease, amylase and inorganic phosphate solubilisation. In addition, antagonistic activity was also tested against Ralstonia solanacearum, Xandhomonas oryzae, Fusarium oxysporum, Alternaria sp., Macrophomina sp., and Magnaporthe oryzae. Further, bioactive compounds from the strain UC1A-3 was analyzed through gas chromatography-mass spectrometric technique. Three strains showed the highest level to promote plant growth promoting and antagonistic activity especially the strain UC1A-3 revealed maximum level of seed germination and increased shoot and root length in Chilli plants. Totally, twenty-nine compounds were detected, most of which were aromatic compound derivatives. In particular, Phthalic acid (C<inf>8</inf>H<inf>6</inf>O<inf>4</inf>), Pentadecanoic acid (C<inf>15</inf>H<inf>30</inf>O<inf>2</inf>), i-Propyl 12-methyltetradecanoate (C<inf>18</inf>H<inf>36</inf>O<inf>2</inf>), l-(+)-Ascorbic acid 2, 6- dihexadecanoate (C<inf>38</inf>H<inf>68</inf>O<inf>8</inf>), 1-Nonadecene (C<inf>19</inf>H<inf>38</inf>), 1-Heptacosanol (C<inf>27</inf>H<inf>56</inf>O) were reported as antimicrobial properties. Findings of the present study evidenced that Streptomyces strain UC1A-3 would be a promising candidate for agricultural crop improvement, since it has showed the potential in-vitro plant growth and biocontrol activities against the tested phytopathogens.

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