Bioconversion of fructose to mannitol by the immobilized Leuconostoc mesenteroides sp. strain JFY on activated carbons in semi-continuous culture

Mannitol: GRAS can be used anticaking, stabilizing, thickening, and texturizing as the food additives, and antioxidant for reducing plasma hydrogen peroxide as the medical treatments. Most commercial mannitol has been synthesized chemically, but strong demand for natural products caused many researchers to study the bioconversion process for mannitol production. This study reported the conversion of fructose to mannitol in a packed bed reactor in semi-continuous mode bacterial cells immobilized on the activated carbons. The strain to convert the fructose to mannitol was isolated from kimches. The immobilized reactor, a 250 x 60 mm glass column with water-cooling jacket, was packed with activated carbons (30 x 80 mesh) and connected to a peristaltic pump. Fructose (5% w/v) was pumped with an downward flow of 5 ml/min and the outlet stream was continuously recirculated into a reservoir and back to the column. Five consecutive batches using fresh medium for each one were carried out at 25℃. The highest yield was obtained at the second batch (86%) and decreased gradually (about 10%) as the batches proceeded.