Ma Ran Jing, Wang Yan Hong, Liu Lu, Bai Lei Lei, Ban Rui
Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, 300072, China.
Department of Biochemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072, China; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, 300072, China.
Protein Expr Purif. 2018 Feb;142:81-87. doi: 10.1016/j.pep.2017.09.011. Epub 2017 Sep 27.
Lipases are among the most versatile biocatalysts, and are used in a range of industrially relevant bioconversion reactions. However, the production of LipA in recombinant Bacillus subtilis is still limited, due to unresolved issues surrounding the regulation of the expression and secretion systems. In this study, the gene encoding LipA from B. subtilis 168 was expressed in BNA under the control of the P and the P promoter. The extracellular lipase activity of the resulting strains BNACL and BNAAL was 7.8 U ml and 12.6 U ml, respectively. To further enhance the expression of LipA, pHP13L was constructed by inserting the P-lip into the shuttle vector pHP13, which produced an extracellular lipase activity of 180.5 U ml of BNA/pHP13L. The strain BNAY8 described in Supplement data which lacks eight extracellular proteins was constructed and the deletion a few of the much weaker secreting proteins had no significant effect on the secretion of LipA. Moreover, the four Sec pathway components, secA-prfB, secDF, secYEG, prsA, were individually overexpressed in BNA. The overexpression of secDF and prsA enhanced the production of LipA by 28% and 49%, respectively. Furthermore, the co-overexpression of secDF with prsA improved the extracellular amount of LipA by 59% over that of BNA/pHP13L, reaching 287.8 U ml. It can therefore be said that both regulatory elements and secretion pathway had an impact on the production of secreted LipA. Their optimization and modification is a useful strategy to improve the homologous overproduction of other extracellular proteins in B. subtilis.
脂肪酶是用途最为广泛的生物催化剂之一,被应用于一系列与工业相关的生物转化反应中。然而,由于围绕表达和分泌系统调控的问题尚未解决,重组枯草芽孢杆菌中LipA的产量仍然有限。在本研究中,来自枯草芽孢杆菌168的LipA编码基因在P和P启动子的控制下在BNA中表达。所得菌株BNACL和BNAAL的胞外脂肪酶活性分别为7.8 U/ml和12.6 U/ml。为了进一步提高LipA的表达,通过将P-lip插入穿梭载体pHP13构建了pHP13L,其产生的BNA/pHP13L胞外脂肪酶活性为180.5 U/ml。构建了补充数据中描述的缺乏八种胞外蛋白的菌株BNAY8,并且缺失一些分泌能力较弱的蛋白对LipA的分泌没有显著影响。此外,在BNA中分别过表达了四种Sec途径组分,即secA-prfB、secDF、secYEG、prsA。secDF和prsA的过表达分别使LipA的产量提高了28%和49%。此外,secDF与prsA的共过表达使LipA的胞外量比BNA/pHP13L提高了59%,达到287.8 U/ml。因此可以说,调控元件和分泌途径都对分泌型LipA的产生有影响。对它们进行优化和修饰是提高枯草芽孢杆菌中其他胞外蛋白同源过量生产的有效策略。