antibiotic from Streptomyces ..

Studies on antibiotic-producing actinomycetes from cave soil in Central region of Thailand

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Empirical antimicrobial therapy may mask the clinical manifestations of actinomycosis, since actinomycetes are extremely susceptible to penicillin and other broad-spectrum antibiotics, and is not recommended.

Final confirmation of the produced antibiotic has been conducted by HPLC and identification of strains was done with PCR and DNA sequencing.

Streptomyces coelicolor and antibiotic production Essay

Actinomycosis is an uncommon, indolent, progressively invasive bacterial infection caused by organisms of the Actinomyces species, which are non-motile, filamentous, branching, gram-positive and predominantly anaerobic bacteria. These organisms belong to the phylum, Actinobacteria, in the order Actinomycetales, and family, Actinomycetaceae. They are related to other genera like Corynebacterium, Propionobacterium, Mycobacteriium and Nocardia.

The actinomycete strain HB-11 isolated from Mumbai port was identified to belong to Streptomyces genus on the basis of aerial and substrate mycelia formation and development of spiral spore chains. The isolate was gram positive and produced dark grey colonies on SCA with blackish colony reverse as represented in Fig.1.


The ability of actinomycetes to form bioactive products is not a fixed property but can be influenced greatly under varying conditions of nutrition and cultivation. Complete knowledge of optimal conditions required for maximum fermentation activity leading to antimicrobial metabolite production by actinomycetes is required so as to standardize the different physical and physiological factors influencing the production of metabolites having antibiotic properties with particular reference to the strain used 16. In view of this, the present research work deals with the isolation of actinomycetes strains from marine soil samples collected from Mumbai Sea port, India, identification of a potent strain capable of producing antifungal compound at species level and optimization of conditions required for production of antifungal compound.

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Changes in the initial pH of the culture medium induce production of new substances that affect antibiotic production 35, hence, we examined the effect of pH on growth and antibiotic production by HB-11 and the results are presented in Figure 5B. The pH 8.0 was found to be the optimum for growth (384.3 mg/100ml) as well as antibiotic production (42 mm). This result is in accordance with most published literature where, optimum pH for antibiotic production in Streptomyces cultures has been reported to be near neutral 36, 15.

Pharmaceutical Sciences And Research

Antibiotic production by S. werraensis was measured by measuring the biomass and size of inhibition zones when the strain was growing on different carbon sources. The strain HB-11 showed maximum cell growth in medium supplemented with glucose but it was not found suitable for antibiotic production. Lactose was not used by the strain for appreciable amounts of biomass and antibiotic production. On the other hand, maximum antibiotic production was observed with complex carbon sources like starch (Figure 5C). Slowly assimilating complex carbon sources like polysaccharides are often known to stimulate secondary metabolite production as these substances do not cause catabolite repression in which production of enzymes of secondary metabolite biosynthesis is inhibited. Complex carbon sources are reported earlier to stimulate antibiotic production by actinomycetes as with starch 37 and cellobiose 38.

Actinomycetes have a long track record of producing novel ..

It is well known that changes in type and concentration of nitrogen sources affect antibiotic synthesis. In the present study also choice of nitrogen source affects antibiotic production by S. werraensis (Figure 5D). Peptone was the best source for growth whereas the addition of ammonium sulphate in medium proved best for maximum antibiotic activity.