Optimization and production of pyrrolidone antimicrobial agent from marine sponge-associated Streptomyces sp. MAPS15.

Twenty-nine actinobacterial strains were isolated from marine sponge Spongia officinalis and screened for antagonistic activity against various bacterial and fungal pathogens. The active antibiotic producer MAPS15 was identified as Streptomyces sp. using 16S rRNA phylogenetic analysis. The critical control factors were selected from Plackett-Burman (PB) factorial design and the bioprocess medium was optimized by central composite design (CCD) for the production of bioactive metabolite from Streptomyces sp. MAPS15. The maximum biomass and active compound production obtained with optimized medium was 6.13 g/L and 62.41 mg/L, respectively. The economical carbon source, paddy straw was applied for the enhanced production of bioactive compound. The purified active fraction was characterized and predicted as pyrrolidone derivative which showed broad spectrum of bioactivity towards indicator organisms. The predicted antimicrobial spectra suggested that the Streptomyces sp. MAPS15 can produce a suite of novel antimicrobial drugs.

Optimization and characterization of a new lipopeptide biosurfactant produced by marine Brevibacterium aureum MSA13 in solid state culture.

The biosurfactant production of a marine actinobacterium Brevibacterium aureum MSA13 was optimized using industrial and agro-industrial solid waste residues as substrates in solid state culture (SSC). Based on the optimization experiments, the biosurfactant production by MSA13 was increased to threefold over the original isolate under SSC conditions with pre-treated molasses as substrate and olive oil, acrylamide, FeCl(3) and inoculums size as critical control factors. The strain B. aureum MSA13 produced a new lipopeptide biosurfactant with a hydrophobic moiety of octadecanoic acid methyl ester and a peptide part predicted as a short sequence of four amino acids including pro-leu-gly-gly. The biosurfactant produced by the marine actinobacterium MSA13 can be used for the microbially enhanced oil recovery processes in the marine environments.