The gene coding for d-psicose 3-epimerase (DPEase) from Clostridium sp. BNL1100 was cloned and expressed in Escherichia coli. The recombinant enzyme was purified by Ni-affinity chromatography. It was a metal-dependent enzyme and required Co2+ as optimum cofactor. It displayed catalytic activity maximally at pH 8.0 and 65 A degrees C (as measured over 5 min). The optimum substrate was d-psicose, and the K (m), turnover number (k (cat)), and catalytic efficiency (k (cat)/K (m)) for d-psicose were 227 mM, 32,185 min(-1), and 141 min(-1) mM(-1), respectively. At pH 8.0 and 55 A degrees C, 120 g d-psicose l(-1) was produced from 500 g d-fructose l(-1) after 5 h.