Authors:R. Baskaran, P. M. Mohan, K. Sivakumar and Ashok Kumar
Actinomycetes, especially species of Streptomyces are prolific producers of pharmacologically significant compounds accounting for about 70% of the naturally derived antibiotics that are presently in clinical use. In this study, we used five solvents to extract the secondary metabolites from marine Streptomyces parvulus DOSMB-D105, which was isolated from the mangrove sediments of the South Andaman Islands. Among them, ethyl acetate crude extract showed maximum activity against 11 pathogenic bacteria and six fungi. Presence of bioactive compounds in the ethyl acetate extract was determined using GC-MS and the compounds detected in the ethyl acetate extract were matched with the National Institute of Standards and Technology (NIST) library. Totally eight compounds were identified and the prevalent compounds were 2 steroids, 2 alkaloids, 2 plasticizers, 1 phenolic and 1 alkane. Present study revealed that S. parvulus DOSMB-D105 is a promising species for the isolation of valuable bioactive compounds to combat pathogenic microbes.
Authors:Satyendra Kumar, Shweta Pahujani, R. P. Ola, R. P. Ola, S. S. Kanwar, S. S. Kanwar and Reena Gupta
A lipase from the thermophilic isolate Bacillus coagulans BTS-3 was produced and purified. The enzyme was purified 40-fold to homogeneity by ammonium sulfate precipitation and DEAE-Sepharose column chromatography. Its molecular weight was 31 kDa on SDS-PAGE. The purified lipase was immobilized on silica and its binding efficiency was found to be 60%. The enzyme took 60 min to bind maximally onto the support. The pH and temperature optima of immobilized lipase were same as those of the free enzyme, i.e. 8.5 and 55ºC, respectively. The immobilized enzyme had shown marked thermostability on the elevated temperatures of 55, 60, 65 and 70ºC. The immobilized enzyme was reused for eigth cycles as it retained almost 80% of its activity. The catalytic activity of immobilized enzyme was enhanced in n-hexane and ethanol. The immobilized enzyme when used for esterification of ethanol and propionic acid showed 96% conversion in n-hexane in 12 h at 55ºC.