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Title
The effect of acetate on the fermentation production of butyrate
Authors
ADAM JAROS ULRIKA ROVA and KRIS A. BERGLUND
Received
May 31, 2011
Published
Volume 46 Issue 5-6 June-July
Keywords
Clostridium tyrobutyricum, butyrate, xylose fermentation, hemicellulose utilization, acetate inhibition
Abstract
A carbon source for the fermentation production of butyrate is xylose extracted from ligno-cellulosic material by hot water extraction. Although this auto-hydrolysis of hemicellulose can provide a low-cost source of xylose, the process generates a high level of acetic acid that might inhibit subsequent fermentations. This study focuses on the effects of acetate on the production of butyrate from xylose by batch fermentations with a selected strain Clostridium tyrobutyricum. At initial acetate concentrations of 17.6 g L-1 and 26.3 g L-1 in the media, C. tyrobutyricum cultures exhibited a lag phase (45 and 118 hours, respectively) in terms of sugar consumption, butyrate production and cell biomass growth, lowering the overall production rate. Butyrate fermentations performed with high concentrations of acetate in the media demonstrated a re-uptake of acetate into the butyrate production pathway and after the lag phase, all cultures adapted to the inhibitory acetate, which increased the final butyrate yields by 12.6% (32.6 g L-1 compared to 28.5 g L-1).
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