Recovery of butanol from Clostridium beijerinckii P260 fermentation broth by supercritical CO2 extraction

Abstract

AbstractBACKGROUNDButanol is a superior biofuel to ethanol because of its blend properties and higher energy density. However, its recovery by distillation from the fermentation broth is energy intensive. For this reason, butanol recovery by supercritical CO2 extraction from simulated and actual fermentation broths was studied. Recovery of butanol by this technique has numerous advantages including being environmentally favorable, avoiding use of costly chemicals or membranes, and compatible with the microbial culture.RESULTSFor the model solution extraction process, feed contained 7.00, 12.00, and 1.00 g L−1 acetone, butanol, ethanol (ABE), respectively, to mimic the actual concentrations obtained in the fermentation broth. In the extract phase, butanol concentration obtained ranged from 460.4 to 573.2 g L−1 with butanol selectivities ranging from 128 to 204.8. ABE recovery was also successfully demonstrated using actual fermentation broth of C. beijerinckii P260.CONCLUSIONSupercritical CO2 extraction was successfully used for recovery of all three (ABE) components. Fermentation broth raffinate (feed depleted in ABE after recovery) was also reused for a second fermentation thus allowing process water recycle. Published 2017. This article is a U.S. Government work and is in the public domain in the USA.