title: Surface display of the thermophilic lipase Tm1350 on the spore of Bacillus subtilis by the CotB anchor protein.
abstract: Lipases expressed in microbial hosts have great commercial value, but their applications are restricted by the high costs of production and harsh conditions used in industrial processes, such as high temperature and alkaline environment. In this study, an Escherichia coli-Bacillus subtilis shuttle vector (pHS-cotB-Tm1350) was constructed for the spore surface display of the lipase Tm1350 from hyperthermophilic bacterium Thermotoga maritima MSB8. Successful display of the CotB-Tm1350 fusion protein on spore surface was confirmed by Western blot analysis and activity measurements. The optimal catalytic temperature and pH of the spore surface-displayed Tm1350 were 80 °C and 9, respectively, which were higher than non-immobilized Tm1350 (70 °C and pH 7.5). Analysis of thermal and pH stability showed that spore surface-displayed Tm1350 retained 81 or 70 % of its original activity after 8 h of incubation at pH 8 or pH 9 (70 °C), which were 18 % higher than the retained activity of the non-immobilized Tm1350 under the same conditions. Meanwhile, recycling experiments showed that the recombinant spores could be used for up to three reaction cycles without a significant decrease in the catalytic rate (84 %). These results suggested that enzyme display on the surface of the B. subtilis spore could serve as an effective approach for enzyme immobilization, which has potential applications in the harsh biochemical industry.
authors.affiliation: Institute of Life Sciences, Jiangsu University, Zhenjiang, 212013, China, 18361811106@163.com.
authors.forename: Huayou
authors.initials: H
authors.lastname: Chen
authors.forename: Rui
authors.initials: R
authors.lastname: Tian
authors.forename: Zhong
authors.initials: Z
authors.lastname: Ni
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: Tianxi
authors.initials: T
authors.lastname: Zhang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.forename: Keping
authors.initials: K
authors.lastname: Chen
authors.forename: Shengli
authors.initials: S
authors.lastname: Yang
mesh_terms: D001412:Bacillus subtilis / Q000502:physiology*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D008049:Lipase / Q000096:biosynthesis* / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics; D013171:Spores, Bacterial / Q000235:genetics / Q000378:metabolism; D020124:Thermotoga maritima / Q000201:enzymology / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; C439051:CotB protein, Bacillus subtilis; D011993:Recombinant Fusion Proteins; D008049:Lipase