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Original Research ARTICLE Provisionally accepted The full-text will be published soon. Notify me

Front. Microbiol. | doi: 10.3389/fmicb.2019.01675

The secretion of Streptomyces monbaraensis transglutaminase from Lactococcus lactis and immobilization on porous magnetic nanoparticles

Tiange Ma1, Jiaojiao Lu1, Jing Zhu2, Xingjiang Li1, Hongwei Gu3,  Manuel Montalban-Lopez4, Xuefeng Wu1, Shuizhong Luo1, Yanyan Zhao1, Shaotong Jiang1, Zhi Zheng1* and  Dongdong Mu1*
  • 1Hefei University of Technology, China
  • 2Anhui Agricultural University, China
  • 3Soochow University, China
  • 4University of Granada, Spain

Microbial transglutaminase (MTG) from Streptomyces mobaraensis is an important enzyme widely applied in food processing for the improvement of protein properties by catalyzing the cross-linking of proteins. In this work we aimed at improving the production and enabling an easy and efficient purification process from culture supernatants. Thus, recombinant vectors, with either a constitutive promoter (Pp5) or an inducible promoter (PnisA), controlling the expression of the MTG gene fused to the signal peptide of Usp45 (SPusp45) were constructed and then expressed in Lactococcus lactis. After purification, 43.5 ± 0.4 mg/L mature MTG-6His was obtained. It displayed 27.6 ± 0.5 U/mg enzymatic activity cross-linking soy protein isolate effectively. The purified mature MTG was immobilized with magnetic porous Fe3O4 nanoparticles, which improved its activity up to 29.1± 0.4 U/mg. The immobilized MTG maintained 67.2% of the initial activity after being recycled for 10 times. The high production and secretion of functional S. mobaraensis MTG from L. lactis and the magnetic immobilized MTG-6His onto Fe3O4 nanoparticles reported in this study would have potential industrial applications.

Keywords: Transglutaminase, Lactococcus lactis, secretion, Signal peptide SPusp45 , Immobilized enzyme

Received: 01 Apr 2019; Accepted: 08 Jul 2019.

Edited by:

Qiang Wang, Institute of Hydrobiology, Chinese Academy of Sciences, China

Reviewed by:

Shang-Tian Yang, The Ohio State University, United States
Per E. Saris, University of Helsinki, Finland  

Copyright: © 2019 Ma, Lu, Zhu, Li, Gu, Montalban-Lopez, Wu, Luo, Zhao, Jiang, Zheng and Mu. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Mx. Zhi Zheng, Hefei University of Technology, Hefei, China, zhengzhi@hfut.edu.cn
Dr. Dongdong Mu, Hefei University of Technology, Hefei, China, d.mu@hfut.edu.cn