Enzymic synthesis of useful chito-oligosaccharides utilizing transglycosylation by chitinolytic enzymes in a buffer containing ammonium sulfate.

A chitinase purified from culture filtrates of Trichoderma resei KDR-11 efficiently catalyzed a transglycosylation reaction on tetra-N-acetylchitotetraoside in a buffer medium containing ammonium sulfate, converting the tetrasaccharide into hexa-N-acetylchitohexaose (39.6%) and di-N-acetylchitobiose (55.7%) as the major products. Sugar-chain elongation from di-N-acetylchitobiose as the initial substrate to hexa-N-acetyl-chitohexaose and hepta-N-acetylchitoheptaose was also efficiently induced through lysozyme catalysis in the presence of ammonium sulfate at high (30%) concentration. In this case, the addition of ammonium sulfate to the reaction system resulted in a remarkable increase of the hexamer and heptamer productions, which are desirable as biologically active oligosaccharides.