Characterization of a thermostable xylanase from a newly isolated Kluyvera species and its application for biobutanol production

► An anaerobic Kluyvera sp. strain OM3 could produce high cellulase-free and thermo-alkali-stable xylanase. ► The xylanase could hydrolyze untreated lignocellulosics to reducing sugars. ► A coculture of Kluyvera sp. strain OM3 and Clostridium sp. strain BOH3 could directly convert xylan to 1.2 g/L butanol.