Enhanced biobutanol production from rice straw with a two-stage packed-bed fermenter coupled with in-line gas stripping

Abstract

BACKGROUND: This study describes the operation of continuous packed-bed reactors containing Clostridium beijerinckii DSM 6422 attached to granular activated carbon to improve butanol productivity and sugar consumption from rice straw hydrolysate. RESULTS: A single-stage fermenter, which was evaluated at dilution rates ranging from 0.3 to 1.8 h−1, achieved a maximum butanol productivity of 4.44 g L−1 h−1 at a dilution rate of 1.2 h−1, corresponding to a sugar consumption of 40%. The performance of the two-stage fermentation plant with in-line gas stripping and effluent recycling was studied at a dilution rate of 1.2 h−1 for each bioreactor, resulting in a butanol productivity of 4.16 g L−1 h−1 in the first stage and 0.98 g L−1 h−1 in the second. Nutrient supplementation was identified as an effective method of enhancing butanol productivity by up to 50% in the second stage. The overall sugar consumption of the two-stage packed-bed reactor with in-line gas stripping was 69%. CONCLUSION: These findings show considerable promise for the future development of lignocellulosic biorefineries, as they demonstrate a potential to achieve economically profitable butanol production. © 2024 The Author(s). Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).