AUTHOR=Jiang Zhanbao , Zhang Chengbo , Tang Minyuan , Xu Bo , Wang Lili , Qian Wen , He Jiandong , Zhao Zhihong , Wu Qian , Mu Yuelin , Ding Junmei , Zhang Rui , Huang Zunxi , Han Nanyu TITLE=Improving the Thermostability of Rhizopus chinensis Lipase Through Site-Directed Mutagenesis Based on B-Factor Analysis JOURNAL=Frontiers in Microbiology VOLUME=11 YEAR=2020 URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.00346 DOI=10.3389/fmicb.2020.00346 ISSN=1664-302X ABSTRACT=

In order to improve the thermostability of lipases derived from Rhizopus chinensis, we identified lipase (Lipr27RCL) mutagenesis sites that were associated with enhanced flexibility based upon B-factor analysis and multiple sequence alignment. We found that two mutated isoforms (Lipr27RCL-K64N and Lipr27RCL-K68T) exhibited enhanced thermostability and improved residual activity, with respective thermal activity retention values of 37.88% and 48.20% following a 2 h treatment at 50°C relative to wild type Lipr27RCL. In addition, these Lipr27RCL-K64N and Lipr27RCL-K68T isoforms exhibited 2.4- and 3.0-fold increases in enzymatic half-life following a 90 min incubation at 60°C. Together these results indicate that novel mutant lipases with enhanced thermostability useful for industrial applications can be predicted based upon B-factor analysis and constructed via site-directed mutagenesis.