ABSTRACT
@#Aim: This study aimed to isolate, express and characterize the lipase derived Psychrobacter sp. S1B in Escherichia coli expression system. Methodology and results: Exploration towards S1B lipase characteristic was conducted where shotgun cloning method was applied to obtain lipase encoded gene and E. coli expression system through pET28a was used to overexpress S1B lipase. Lipase activity was measured by using p-nitrophenol method. The S1B lipase gene is 1005 bp in length with molecular weight of 46 kDa, optimum pH was 10.0, showed hydrolytic activity preference toward p-nitrophenyl caprylate (C8) and p-nitrophenyl hexanoate (C6) substrates (C6 < C8). The best temperature for S1B lipase activity was at 30 °C while exhibited high activity at lower temperature (10-25 °C) with above 90% of maximum activity, therefore it is classified as cold adaptive lipase. In addition, S1B lipase showed stability against various metal ions, including Cu2+ and Zn2+ which commonly act as inhibitors of lipases derived from Psychrobacter species. Moreover, S1B lipase exhibited great tolerance against up to 50% (v/v) hexane and some non-ionic detergents such as 1% (v/v) DMSO and 1% (v/v) Triton X-100. Conclusion, significance and impact of study: The study proposes a novel cold-adapted lipase which has potential as a biocatalyst for synthesis caprylic acid ester
ABSTRACT
Temperature-sensitive yeast mutants were used to screen for cell cycle-related genes from Pleurotus eryngii genomic DNA. A mushroom genomic DNA library was established and each gene was screened for the ability to rescue seven Saccharomyces cerevisiae temperature-sensitive strains. Hundreds of yeast transformants were selected at restrictive temperatures over 30degrees C. Plasmids from the transformants that survived were isolated and transformed back into their host strains. The temperature sensitivity of the resulting transformants was tested from 30degrees C to 37degrees C. Ten DNA fragments from P. eryngii were able to rescue yeast temperature-sensitive strains, and their DNA sequences were determined.
Subject(s)
Agaricales , Base Sequence , Cell Cycle , DNA , Gene Library , Mass Screening , Plasmids , Pleurotus , Saccharomyces cerevisiae , YeastsABSTRACT
pFH23. These studies provide the possibility of further research on the expression of recombinant antigenic genes, the immunity of their expressed products and the protection of animals.