Screening and chemical analysis of antifungal compounds from actinomycetes
Keywords:Streptomyces, actinomycetes, anti-fungal, fillipin III, polyene
Fungal infections are a serious problem in agriculture, health and food preservation industry. The chemically synthesized compounds are able to inhibit fungi in a certain degree. However, these compounds have a lot of disadvantages such as lack of specificity and can accumulate in the environment, some compounds are even harmful to humans. Thus, antifungal compounds derived from microorganisms are always of interest, especially antifungal polyenes from actinomycetes. This is a group of antifungal substances have been known for a long time but have a very wide spectrum. Therefore, we conducted this study to find actinomycete strains isolated in Vietnam that are able to produce antifungal polyenes. Screening results from 500 actinomycete strains preserved at VTCC showed that 7 strains had strong activity against Saccharomyces cerevisiae. Optimal culture conditions for the 7 strains to produce the highest amount of active compounds were also determined. The study results illustrated that all 7 strains belonged to the genus Streptomyces and produced antifungal polyenes. Among the 7 strains, strain VTCC-A-2787 Streptomyces misionensis had specific and high activity against yeasts and filamentous fungi. The active compound produced by this strain has been purified and determined as Filipin III. This is the first study which revealed the ability of producing Filipin III by S. misionensis.