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).