Whole-cell biocatalysis of maleic acid into L-aspartic acid by dual-enzyme coupling

Expand
  • (School of Biotechnology and the Key Laboratory of Industrial Biotechnology, Jiangnan University, Wuxi 214122, China)

Online published: 2018-09-13

Abstract

As a staple amino acid product, L-aspartic acid has been widely used in food, medicine and chemical industries. Six different maleate cis-trans isomerase and L-aspartic acid amino lyase co-expression systems have been built in E. coli BL21 (DE3) ΔfumAC in this study. By comparing their co-expression results and catalytic efficiency, the optimal co-expression system E. coli BL21 (DE3) ΔfumAC/pRSFDuet-1-maiA-aspA was obtained. 3.2 mol/L of maleic acid was completely transformed into L-aspartic acid ammonium in 390 minute with OD600 of 8. The concentration of L-aspartic acid ammonium reached 3.14 mol/L, conversion rate was above 98%, and the intermediate fumaric acid had almost no accumulation overall the reaction progress. Furthermore, to solve the problem that is difficult to recycle cells in high concentration of viscous reaction liquid, cell immobilization was studied. After 8 recycles of the immobilized cells, the relative enzyme activity was still 81%. The result suggested that the utilization rate of cells were greatly improved and the production cost reduced, which laid the foundation for the future industrial production of L-aspartic acid.

Cite this article

YU Long et al . Whole-cell biocatalysis of maleic acid into L-aspartic acid by dual-enzyme coupling[J]. Food and Fermentation Industries, 2018 , 44(8) : 20 -26 . DOI: 10.13995/j.cnki.11-1802/ts.016966

Outlines

/