Biosynthesis of 5-adenosylmethionine by immobilized whole cell of E. Coli JM109 (pBR322-MAT)

The methionine adenosyltransferase (MAT) gene is cloned from the genome of E. Coli-K12, and the recombinant E. Coli JM109(pBR322-MAT) strain which can highly express MAT is constructed. The whole cells of E. Coli JM109 (PBR322-MAT) are immobilized in Ca-alginate(CA) gel. The optimal mass concentration of CA is 20 g/L and the optimal cell loading by direct entrapment is 0.15 g of wet weight cells per mL gel. After 5 batches of reaction, the enzyme activity decreases to 91% of the initial. For the biosynthesis of S-adenosylmethionine by immobilized cell, the conversion rate based on the amount of ATP can be over 95 % under the optimal conditions.