Study on Thermostability of Bacillus Subtilis Lipase by Site-Directed Mutagenesis

Abstract

BSLA is an extracellular hydrolase secreted by Bacillus subtilis, which is an enzyme at room temperature and its optimum temperature is only 35 °C. Thermal stability is an important indicator for the evaluation of industrial biocatalysts. The industrial increase of reaction temperature can improve the conversion rate, the solubility of the substrate and the possibility of reducing the microbial contamination. Therefore, by improving the heat resistance of BSLA through molecular modification, Adapt to the requirements of industrial production process, has important practical value. The mutant BSLAN174E was constructed by whole plasmid PCR and the thermal stability of the mutant strain was verified by experiments. After the purified BSLA and BSLAN174E enzyme solutions were stored at 55 °C for 5, 20 and 60 min respectively, the relative residual activity of BSLAN174E Respectively 1.6, 2.0, 2.3 times of the original strain BSLA.