Abstract
Conversion of food wastes into L(+)-lactic acid by simultaneous saccharification and fermentation (SSF) was investigated. The process involves saccahrification of food wastes by a commercial amyloytic enzyme preparation (a mixture of amyloglucosidase, -amylase and protease) and fermentation by a lactic acid bacterium. Several microorganisms, such as a L. delbreukii, L. helveticus, L. salivarius, L. casei and L. lactis, were tested for their L(+)-lactic acid productivity. Among the microorganisms tested, L. casei produced the most pure L(+)-lactic acid(over 91% of total lactic acid produced) with a total lactic acid yield of 78%. L. delbreukii produced the highest total lactic acid yield(99%) with about 60% of L(+)-lacitic acid purity. In the SSF with no nitrogen supplements, 27 g/L(yield 27%) of L(+)-lactic acid was produced from 100 g/L food waste.
