The research topics of AB group involve separation and purification of biological products. Since many fermentation products exhibit product inhibition effect, extractive fermentation can significantly enhance product yield and volumetric productivity. These products include alcohols and organic acids. Various techniques developed in our laboratory have shown a high potential for commercialization; for example, extractive fermentation of ethanol using vacuum fractionation technique, external precipitation of lactic acid and succinic acid by calcium hydroxide, etc. In addition, esterification of these acids with ethanol followed by dehydration using vapor permeation results in a complete conversion of organic acids to esters. After distillation and hydrolysis, a high purity of lactic acid or succinic acid can be obtained.