Studies on the Production of Broad Spectrum Antimicrobial Compound Polypeptide (Actinomycins) and Lipopeptide (Fengycin) from Streptomyces sp. K-R1 Associated with Root of Abutilon indicum against Multidrug Resistant Human Pathogens

Abstract

Endophytic actinomycetes associated with medicinal plants of Chhattisgarh are rich source of novel antimicrobial compounds. The aim of this study was to evaluate the production of antibiotics by endophytic Streptomyces sp. K-R1 associated with root of Abutilon indicum against multidrug resistant human pathogens. The 16S rRNA sequence of the isolate K-R1 has been identified as Streptomyces parvulus NBRC 13193T (AB184326) with the GenBank database (accession number KY777591). Streptomyces parvulus K-R1 grown under submerged fermentation condition optimized by central composite design (glucose—11.25 g/l, soybean meal 12.17 g/l, calcium carbonate—1.47 g/l, sodium chloride—11.25 g/l; pH 7.18 at 30.51 °C with 4% seed inoculum for 10 days of incubation) exhibited highest activity against multidrug resistant Staphylococcus aureus JNMC-3, Staphylococcus epidermidis JNMC-4, Klebsiella pneumoniae MTCC-3384, Klebsiella pneumoniae JNMC-6, Pseudomonas aeruginosa MTCC-741, Proteus vulgaris JNMC-7, Candida albicans MTCC-183 and Aspergillus niger MTCC-872. The structures of the active compounds were elucidated by UV–Vis spectroscopy, 1H and 13C NMR, FTIR and ESIMS. Actinomycin D, actinomycin X0β and fengycin were detected in crude extracts and major components were eluted by HPLC at 10.63, 10.88 and 6.3 min respectively. In this case, a high yield of antibiotics was achieved with Streptomyces parvulus K-R1 fermented in glucose soybean meal broth media with a production of 240 mg/l after 5 days, 290 mg/l after 8 days and 340 mg/l after 11 days, which can be used in industrial fermentation process to obtain high yields. To the author’s best knowledge, it is the first report of fengycin production by Streptomyces parvulus.