P24 Butyric acid from anaerobic fermentation of lignocellulosic biomass hydrolysates by Clostridium sp. strain RPT-4213
Monday, July 21, 2014
Siqing Liu1, Kenneth M. Bischoff1, Timothy D. Leathers1, Nasib Qureshi2, Joseph O. Rich1 and Stephen R. Hughes1, (1)Renewable Product Technology, National Center for Agricultural Utilization Research, USDA-ARS, Peoria, IL, (2)Bioenergy Research Unit, National Center for Agricultural Utilization Research, USDA-ARS, Peoria, IL
A novel Clostridium sp. strain RPT-4213 was found producing butyrate under strict anaerobic conditions.  This strain produced 9.47 g L-1 butyric acid from MRS media (0.48 g/g glucose).  RPT-4213 was also used to ferment dilute acid pretreated hydrolysates including wheat straw (WSH), corn fiber (CFH), corn stover (CSH), rice hull (RHH), and switchgrass (SGH). Results indicated that 50% WSH with a Clostridia medium (Ct) produced the most butyric acid (8.06 g L-1, 0.46 g/g glucose), followed by 50% SGH with Ct (6.01 g L-1, 0.44 g/g glucose), however, 50% CSH Ct showed growth inhibition. RPT-4213 was then used in pH-controlled bioreactor fermentations using 60% WSH and SGH, with a dilute (0.5 x) Ct medium, resulting 9.87 g L-1 butyric acid in WSH (yield 0.44 g/g) and 7.05 g L-1 butyric acid in SGH (yield 0.42 g/g).  The titer and productivity could be improved through process engineering.