PRODUCTION OF ANTIBIOTIC SUBSTANCES BY ACTINOMYCETES (original) (raw)
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Journal of Fermentation and Bioengineering, 1993
During screens for novel secondary metabolite natural products, actinomycete isolates are often encountered which show antibiotic activity on agar but not in liquid culture. In this study, it was found that the liquid culture morphology of Streptomyees species, producing antibiotic on solid media only, was fragmented compared with that of the filamentous mycelia of antibiotic-producing Streptomyces. An enrichment culture method which selected for a more filamentous liquid culture morphology was successful in providing active liquid cultures of the isolates which had previously been active only in agar culture. After repeating the selection procedure five times with several cultures, two stable phenotypes with antibiotic activity in liquid culture and a filamentous morphology were obtained. The correlation of a filamentous morphology with antibiotic production in liquid culture is discussed.
“ Search for Antimicrobial Agents Produced by the Soil Actinomycetes ”
2014
Actinomycetes are biotechnologically important bacteria which are well exploited for secondary metabolites. Screening, isolation and characterization of capable strains of actinomycetes producing potential secondary metabolites has been a most important area of research by many groups worldwide for many years. Actinomycetes are the foundation of the antibiotics industry and hold a significant role in producing variety of drugs that are extremely vital to our health and nutrition. Research has been demonstrate that a large number of antimicrobial agents have been produced from the soil. One of the first antibiotics used is streptomycin produced by Streptomyces griseus. Among Actinomycetes, approximately 7600 compounds are produced by Streptomyces species. The actinomycetes are a group of grampositive bacteria that exhibit characteristics of both bacteria and fungi. The genus Streptomyces is responsible of the synthesis of the majority of antimicrobial agents with clinical importance ...
Microbial Production of Antimicrobial Agents
2019
In a trial to search for a new antibiotic producer a terrestrial actinomycete was isolated from AL-alameen soil which proved to be a potential candidate for the production of active metabolites against E. coli 25922 and Staphylococcus aureus 25923. It was identified phenotypicallyas Streptomyces sp. The optimum activity was obtained when the organism was grown on glycerol as a sole carbon source at 30°C and pH 7.0 for 192 h. The highest metabolic activity noticed intracellulary and it was approved with MIC values. In a trial to test the combined activity of the extract and some antibiotics; synergistic action was noticed with ceftriaxone. Further investigations were applied to the extract for its active components using TLC and GC-MS which indicated that Pentadecanoic acid, 14-methyl-, methyl ester; Hexadecanoic acid, methyl ester and 2,4-bis(1,1- dimethylethyl)- Phenol were the potent active components. Toxicity test was evaluated for the active components as well as the crude extract.
Characterization Of Actinomycetes Producing Novel Antibiotics
Biolife, 2023
Actinomycetes that may have good potential of producing novel antibiotics against coal mine soil MMKK2 gram positive bacteria most of the isolates (46%) also showed antimicrobial activity Streptomyces rochei. These bacteria are known capable of producing secondary and primary metabolites isolation and characterization of actinomycetes were conducted by serial dilution, pour plate method on GAAM, SCA Medias while characterization was by determining morphological, physiological, ecological and genetic analysis of colonies, cell structure and biochemical tests. The results solved by 16SrDNA sequence analysis showing Antibiotic activity related to the genus Streptomyces followed by Microbacterium, Agromyces, Bacillus megaterium, rare antibacterial genera accounted for minor proportions
Pageantagonistic Activity of Actinomycetes on Some Gram Negative and Gram Positive Bacteria
World applied sciences journal, 2010
In the present research, In vitro study of antagonistic properties of fifty soil actinomycetes against 10 bacteria which were: Salmonella typhi, Klebsiella pneumoniae, Serratia marsecense, E. coli, Proteus vulgaris, Streptococcus faecalis, Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and Micrococcus luteus showed that Six of them have inhibitory effects on both gram negative and gram positive pathogenic bacteria by using agar disk diffusion method. Of all six active Actinomycetes isolates, one of them named Streptomyces plicatus No. 24 was selected for further study on the basis of (a) broad spectrum activity and (b) larger inhibition zone against pathogen growth, in comparison with others. Minimum Inhibitory Concentration (MIC) of the crude culture filtrate of S. plicatus against Staphylococcus aureus was determined as 0.004 mg ml . Gram positive pathogenic bacteria were more sensitive to its metabolites than gram negative 1 ones. A commercial product containing S. pli...
Effect of Carbon and Nitrogen sources on the antibiotic production by local isolate of Streptomyce s sp.Zl, 2008
The genus Streptomyces consists of sporulating Gram-positivesoil bacteria with a mycelia growth habit, and a life cycle with complex morphological and physiological differentiation, also piodu.., antibiotics which are the secondary metabolite. The objective of the present study is to study of an ability of a local isolate of Streptomyces Zl to produce antibacterial substance, and effect of different carbon and nitrogen sources on antibacterial production. Results in present study showed that Streptomyces Zl have ability to produce antimicrobial agent against Escherichia coli, Shigella dysentery, Pseudcimonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, Staphylococcus epidermidis, Bacillus nrbtilis which indicated by diameter of inhibition zone that reached tol6.0, 19.3, 18.1,25.0, g.z, 11.2, l2.o mm, respectively, iesults in this study showed that antimicrobial agent produced by Streptomyces Zl lvas more effective against gram negative organisms rather tlian gram positive. Production of antibiotics from microorganisms varies with the constituents of the media. In present study we have investigated the influence of medium constituents such as carbon and nitrogen soui.., on
Streptomycetes: Characteristics and Their Antimicrobial Activities
The Streptomycetes are gram positive bacteria with a filamentous form that present in a wide variety of soil including composts, water and plants. The most characteristic of Streptomycetes is the ability to produce secondary metabolites such as antibiotics. They produce over two-thirds of the clinically useful antibiotics of natural origin (e.g., neomycin and chloramphenicol. Another characteristic of Streptomycetes is making of an extensive branching substrate and aerial mycelium.Carbon and nitrogen sources, oxygen, pH, temperature, ions and some precursors can affect production of antibiotics. This review also addresses the different methods to study the antimicrobial activity of Streptomyces sp. Because of increasing microbial resistance to general antibiotics and inability to control infectious disease has given an impetus for continuous search of novel antibiotics all the word.