The production of succinic acid by yeast Yarrowia lipolytica through a two-step process

The production of alpha-ketoglutaric acid by yeast Yarrowia lipolytica VKMY-2412 from ethanol and its subsequent chemical conversion to succinic acid (SA) were investigated. A highly effective and environmentally friendly process of alpha-ketoglutaric acid production was developed using a special pH-controlling strategy, in which the titration of the culture broth with KOH in the acid-formation phase was minimal, that allowed accumulation of only low amounts of inorganic wastes in the course of SA recovery. The culture broth filtrate containing alpha-ketoglutaric acid (88.7 g l(-1)) was directly employed for SA production; the amount of SA produced comprised 71.7 g l(-1) with the yield of 70 % from ethanol consumed. SA was isolated from the culture broth filtrate in a crystalline form with the purity of 100 %. The yield of isolated SA was as high as 72 % of its amount in the culture broth filtrate. The antimicrobial and nematocidic effects of SA of microbial origin on pathogenic organisms that cause human and plant diseases were revealed for the first time.