Bio-based Esters for a Smaller Footprint
By: Katie Schaefer, Cosmetics & Toiletries magazine
Posted: February 27, 2009, from the March 2009 issue of Cosmetics & Toiletries.
Succinic acid is a four-carbon dicarboxylic acid that occurs naturally in plant and animal tissues. It plays a biochemical role in the citric acid cycle, or Krebs cycle, as part of cellular respiration. Today, succinic acid is commercially produced from fossil-based feedstocks via catalytic hydrogenation of maleic anhydride or as a byproduct of adipic acid production. This carboxylic acid can be used to produce acyl halides, carboxylic acid salts, anhydrides, esters, amides, imides, nitriles, butane diol and other materials for use in a number of industries, including resins, fibers, plastics, personal care, pharmaceuticals and agriculture.
Succinic acid is produced commercially from maleic anhydride via petrochemical processes; maleic anhydride in turn is derived from n-butane or coal. The refining of fossil-based feedstocks to produce petrochemicals leads to the emission of harmful gases into the environment.
In keeping with its green chemistry motif, DNP Green Technology, an industrial biotechnology company, has licensed a fermentation method from the US Department of Energy (USDE) to process succinic acid on a larger scale and in a more eco-friendly manner, which the company expects will benefit both the environment and the consumer. Dilum Dunuwila, PhD, vice president of business development for the company, is excited about the bio-based production of succinic acid. “We’ve taken the fermentation process developed by the USDE and scaled it up,” said Dunuwila.
The Lifecycle of Carbon
According to Dunuwila, nearly 50,000 metric tons of succinic acid are produced petrochemically per year. He adds that “it’s relatively expensive [to produce] and is made from a finite resource that is imported and highly susceptible to volatility driven by economic and geopolitical crisis.” To petrochemically produce succinic acid, carbon is obtained from fossil deposits. Dunuwila notes, “Refining and processing fossil-based carbon leads to CO2 accumulation in the atmosphere.” In contrast, the new bio-based process consumes CO2 rather than emitting it, providing the long-term potential to generate carbon credits for potential manufacturers. “We have a much lower carbon footprint,” continued Dunuwila. “Since we utilize renewable crops and CO2 to produce succinic acid, we complete the cycle of carbon.”
The process is based on an Escherichia coli bacteria that metabolize glucose produced from corn, wheat tapioca, sugarcane and cellulose. “We feed the glucose produced by these crops to the E. coli and succinic acid is produced as a metabolite of E. coli,” explains Dunuwila.