Enzymatic Synthesis of L-Cysteine by Escherichia coli Whole-Cell Biocatalyst

摘要

In this study, the bioconversion process from dl-ATC to l-cysteine was developed by E. coli whole-cell biocatalyst, and the catalytic conditions were explored and optimized. Heterologous expression of the l-ATC hydrolase and l-NCC amido-hydrolase in E. coli enabled us to construct an efficient whole-cell biocatalyst, and reduction of the activity of l-cysteine desulfhydrase in E. coli further increased the accumulation of L-cysteine. Effects of various reaction conditions, including pH, temperature and glycerol concentration on catalytic activities and l-cysteine production were examined, and the optimal conditions were determined. Under the optimized conditions, the production of l-cysteine reached up to 70.2 mM after 8 h whole-cell catalysis. This study provides a new economical and environment-friendly route for large-scale production of l-cysteine.