Efficient production of 3,6-anhydro-L-galactose from red algal neoagarobiose by whole-cell biocatalysis of recombinant Corynebacterium glutamicum

초록

3,6-Anhydro-L-galactose (AHG) is a potent food and cosmetic ingredient affecting the anticariogenic and antimelanogenic activities of red algal polysaccharides. For efficient AHG production instead of enzymatic process, whole-cell biocatalyst of recombinant Corynebacterium glutamicum CG-H4-NABH with an alpha-neoagarobiose hydrolase (NABHase) dividing red algal neoagarobiose (NAB) to AHG and D-galactose was developed. To prepare high concentration of the biocatalyst, fed-batch cultivation of CG-H4-NABH yielded 71.8 g/L dry cell mass and 58.9 U/mL NABHase activity. For efficient transport and hydrolysis of NAB and elevating AHG production, the CG-H4-NABH cells permeabilized by toluene showed 37 times higher activity than the untreated cells. After seven cycles of repeated whole-cell reaction, the permeabilized-immobilized cells exhibited a 3.6 times higher NAB-hydrolyzing rate and a 1.6-fold higher cumulative AHG concentration than the permeabilized free-cells. Conclusively, the whole-cell biocatalysis using C. glutamicum could serve as an efficient and alternative process for production of monosaccharides by disaccharide hydrolysis.

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