Improving biocatalytic microenvironment with biocompatible ε-poly-l-lysine for one step gluconic acid production in low pH enzymatic systems. (January 2019)

• Record Type: Journal Article
• Authors: Huang, Jinsha; Zhuang, Wei; Ge, Lei; Wang, Kai; Wang, Zhenfu; Niu, Huanqing; Wu, Jinglan; Zhu, Chenjie; Chen, Yong; Ying, Hanjie
• Is Part Of: Process biochemistry. Volume 76(2019)
• Page Start: 118
• Page End: 127
• Publication Date: 2019-01
• Subjects: Amination -- Microenvironment -- ε-Poly-l-lysine -- Gluconic acid -- Multi-enzyme immobilization; Biochemical engineering -- Periodicals; Biotechnology -- Periodicals; Biochemistry -- periodicals; Biotechnology -- periodicals; Chemical Engineering -- periodicals; Génie biochimique -- Périodiques; Biotechnologie -- Périodiques; Biochemical engineering; Biotechnology; Periodicals; 660.63
• DOI: 10.1016/j.procbio.2018.10.018
• Languages: English
• ISSNs: 1359-5113

Abstract

Graphical abstract: Highlights: The ε-poly -l - lysine (EPL) amino donors do less harm to the conformation of enzymes. Amine modification improves the microenvironment near the active sites of enzyme. The gluconic acid production of modified enzymes in low pH was improved by 1.44 times. Activity recovery of immobilized EPL@GOx&CAT increased to 1.56 times higher than that of unmodified. Abstract: Surface amine modification could not only improve the microenvironment near the active sites of enzyme, but also enhance the multi-point chemical crosslinking between the enzyme and carrier. The linear structured polymer of ε-poly -l - lysine (EPL) is an ideal donor of amino with much more exposed on the surface for enzyme attachment. Analysis of the result of dynamic light scattering (DLS) and circular dichroism (CD) demonstrated the favorable electrostatic interactions and negligible impact on the conformation of enzymes, Glucose Oxidase and Catalase (GOx&CAT). Titration and dissociation curve together with Zeta-potential characterization revealed that enzymes (EPL@GOx&CAT) under the protection of EPL had more stable structure and better activity and stability in acidic reaction environment. Meanwhile, the activity recovery of immobilized EPL@GOx&CAT increased to 1.56 times higher than that of GOx&CAT, and the acid resistance was improved by 1.44 times with the optimum pH shifting to acidic by 0.50 unit. The substrate affinity was raised with the decrease of Km from 5.98 to 4.35 mg mL −1 . Thus, the gluconic acid production in low pH system could be increased by pH-engineering of the enzyme microenvironment via conjugation with positively charged polyelectrolyte.