UTILIZATION OF WHITE GRAPE POMACE FOR LACTIC ACID PRODUCTION

White grape pomace (WGP) contains high amount of soluble carbohydrates (glucose and fructose), which can potentially be used as a carbon source in the fermentative production of bio-based chemicals. In this study, this waste was valorized by lactic acid (LA) production by Lactobacillus casei. Adding WGP directly into the culture medium at a solid loading of 10% yielded 33.3 g/L LA. Water extract of WGP allowed comparably faster LA production. Increasing the solid loading in the extraction step increased the LA titers, however, it had a significant negative effect on the production rate. In all cases, fructose was consumed at a slower rate as compared to glucose. Yeast extract powder was required at a concentration of 10 g/L to support LA production. Alternatively, baker’s yeast was autolyzed and the lysate was successfully used as the nitrogen source. The findings show that WGP can be regarded as a sustainable plant-based feedstock for LA production by L. casei, however, the probable negative effect of other pomace constituents should be avoided.