S121: Genetic engineering of E. coli for the production of succinate from glycerol

Succinic acid is currently a product from the petrochemical industry that is useful as a monomer for biodegradable plastic polymers.  Myriant Technologies, Inc. has developed an economically attractive fermentation process for producing succinate from glucose, sucrose, or sorghum, using a genetically engineered strain of E. coli.  This process will provide inexpensive succinate that can be used directly, or as a chemical intermediate for the production of other products, such as 1,4-butanediol.

            Glycerol is a major byproduct from the triglyceride transesterification process of the biodiesel industry.  About 0.1 kg of glycerol is produced for every kg of biodiesel.  It is estimated that about 400 million gallons of biodiesel were produced in 2010 in the United States, which implies that 40 million gallons of glycerol were produced.  With the growth of the biodiesel industry, the increase in supply of glycerol has caused the price of crude glycerol to fall to as little as $0.05/lb.  As such, glycerol has become attractive as an inexpensive fermentation feedstock.

            Starting with Myriant’s glucose utilizing strain of E. coli, we have used genetic engineering techniques and metabolic evolution to construct a new strain that is capable of producing succinate from glycerol.  The titers, specific rates of production, yields, and byproducts from glycerol-fed fermentations are comparable to those from glucose-fed fermentations using the parent strain.  Information on the strain construction process and fermentations will be presented.