Abstract
ObjectivesTo improve the fermentation production of transglutaminase (TGase) from Streptomyces mobaraensis for applications in the food industry, the atmospheric and room-temperature plasma (ARTP) mutagenesis was applied to breed S. mobaraensis mutants with increased TGase production.ResultsAfter eight rounds of iterative ARTP mutagenesis, four genetically stable mutants, Sm5-V1, Sm6-V13, Sm2-V10, and Sm7-V12, were identified, which showed increased TGase production by 27, 24, 24, and 19%, respectively. The best mutant Sm5-V1 exhibited a maximum TGase activity of 5.85 U/mL during flask fermentation. Compared to the wild-type strain, the transcription levels of the zymogen TGase genes in the mutants increased significantly as indicated by quantitative real-time PCR, while the gene nucleotide sequences of the mutants did not change at all. It was shown that the overexpression of TGase zymogen gene in the mutants contributes to the increase in TGase production.ConclusionsARTP is a potentially efficient tool for microbial mutation breeding to bring some significant changes required for the industrial applications.
Highlights
Transglutaminases (TGase, EC 2.3.2.13), referred to protein-glutamine γ-glutamyltransferases, are enzymes capable of catalyzing acyl-transfer reactions between the γ-carboxamide group of protein or peptide-bound glutamine and ε-amino group of lysine or other primary amines (Zhu et al 1995; Martins et al 2014)
Streptomyces mobaraensis, the wild-type strain (S. mobaraensis ECU7480, stored in our lab) and the mutants generated by ARTP mutagenesis, were grown on a solid medium comprising 20 g/L soluble starch, 3 g/L tryptone, 1 g/L KNO3, 0.5 g/L K 2HPO4·3H2O, 0.5 g/L M gSO4·7H2O, 0.5 g/L NaCl, 0.01 g/L FeSO4·7H2O, and 1.5–2.0% (w/v) agar at pH 7.4–7.6 and 30 °C for 5 days
The lethal rates of S. mobaraensis with respect to various treatment times are shown in Fig. 2, which indicated that the lethal rate increased to 66.5, 93.1, and 99.2%, respectively, after treated for 30, 40, and 50 s
Summary
Transglutaminases (TGase, EC 2.3.2.13), referred to protein-glutamine γ-glutamyltransferases, are enzymes capable of catalyzing acyl-transfer reactions between the γ-carboxamide group of protein or peptide-bound glutamine and ε-amino group of lysine or other primary amines (Zhu et al 1995; Martins et al 2014). The covalent modifications of proteins promoted by TGase facilitate extensive applications in food, medicine, and other industries. TGases are widely distributed in prokaryotes and eukaryotes. TGases from animal tissues are Ca2+-dependent enzymes that lead to the precipitation. (2017) 4:37 efficient protein folding, secretion, and suppression of the enzymatic activity (Yurimoto et al 2004). Considering the fact that genetically engineered strains are somehow restricted in the food industry, it is more feasible to improve TGase production by mutation breeding
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
