Heterologous expression of recombinant transglutaminase in Bacillus subtilis SCK6 with optimized signal peptide and codon, and its impact on gelatin properties.

In this study, the MTG gene of Streptomyces sp. TYQ1024 was cloned and expressed in a food-grade bacterial strain Bacillus subtilis SCK6. Extracellular activity of MTG after codon and signal peptide (SP Ync M) optimization was 20 times that of the pre-optimized enzyme. After purification, the molecular weight of MTG was 38 kDa and the specific activity was 63.75 U/mg. The optimal temperature and pH for recombinant MTG activity were 50 °C and 8.0, respectively. MTG activity increased 1.42-fold in the presence of β-ME and 1.6-fold in the presence of DTT. Besides, 18% sodium chloride still resulted in 83% enzyme activity which showed good salt tolerance. Cross-linking gelatin with MTG increased the strength of gelatin 1.67 times and increased the thermal denaturation temperature from 61.8 to 75.8 °C. MTG significantly increased the strength and thermal stability of gelatin. These characteristics demonstrated the huge commercial potential of MTG, such as its application in salted protein foods.
PMID: 32325545 [PubMed - as supplied by publisher]

Source: Journal of Microbiology and Biotechnology - April 22, 2020 Category: Biotechnology Authors: Shiting W, Zhigang Y, Zhenjiang L, Yongqiang T Tags: J Microbiol Biotechnol Source Type: research