Deacylation of Echinocandin B by Streptomyces species: a novel method for the production of Echinocandin B nucleus.

Anidulafungin, a new class of antifungal agent used for the treatment of chronic fungal infections, is derived from Echinocandin B nucleus, an intermediate metabolite of Echinocandin B produced by Aspergillus nidulans. The enzyme acylase plays a key role in the bioconversion of Echinocandin B to Echinocandin B nucleus. In the present study, a rapid screening method was used to select an actinomycete capable of producing Echinocandin B acylase. Out of 140 actinomycetes screened for the production of acylase by preliminary qualitative plate assay, 53 were selected. The selected isolates were subjected to quantitative assay under submerged fermentation for the bioconversion of Echinocandin B to Echinocandin B nucleus. Among 53 strains of actinomycetes, two strains (BICC-8848 and BICC-8547) exhibited higher degree of acylase activity. Various physico-chemical parameters were optimised for maximum bioconversion of ECB to ECB nucleus. It was found that the conditions viz. pH 7.0, temperature 26 °C and substrate concentration of about 4 g/L supported higher degree of bioconversion. It was also observed that, as the medium volume increased to 500 mL, the conversion rate was also increased by more than two-folds. © King Abdulaziz City for Science and Technology 2019.