Soybean Carbohydrates as a Renewable Feedstock for the Fermentative Production of Succinic Acid and Ethanol

Soybeans are an abundant and relatively inexpensive source of protein that are widely recognized for their high nutritional value in food and as animal feed supplements. In addition to protein and oil, carbohydrates consisting of cellulose, hemicellulose, low molecular weight sugars, sucrose and oligosaccharides such as verbascose, stachyose, and raffinose represent 35-40% of seed. Soy oligosaccharides are not readily digested by monogastric animals due to the lack of an enzyme that can effectively hydrolyze the galactosides, such as a-galactosidase. As a result the oligosaccharide portion is considered anti-nutritional. Because they constitute a rich source of amino acids and carbohydrates, soybean derived feedstocks such as soybean meal, soy hulls, and soy molasses represent an inexpensive source of fermentable carbohydrates for biobased production of valuable compounds. This chapter describes developments in the field of microbial metabolism of soy carbohydrates, acid and enzyme hydrolysis of oligosaccharides, and biobased production of succinic acid and renewable fuel ethanol using soybean carbohydrate feedstocks. (C) 2014 American Chemical Society