Lactulose production from lactose as a single substrate by a thermostable cellobiose 2-epimerase from Caldicellulosiruptor saccharolyticus

• Published in: Bioresource technology Vol. 104; pp. 668 - 672
• Main Authors: Kim, Yeong-Su, Oh, Deok-Kun
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2012
• Subjects: Caldicellulosiruptor; Caldicellulosiruptor saccharolyticus; cellobiose; Cellobiose - chemistry; Cellobiose 2-epimerase; Enzyme Activation; Enzyme Stability; Enzymes; Epilactose; Lactose; Lactose - chemistry; Lactulose; Lactulose - chemical synthesis; Lactulose production; Productivity; Racemases and Epimerases - chemistry; Recombinant; Substrate Specificity; Synthesis; Temperature; Thermoanaerobacter - enzymology; Cellobiose 2-epimerase; Lactose; Caldicellulosiruptor saccharolyticus; Epilactose; Lactulose production
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2011.11.016

► Caldicellulosiruptor saccharolyticus cellobiose-2-epimerase produced lactulose. ► The enzyme synthesized first lactulose using the single substrate lactose. ► The enzyme produced also epilactose as another bifidus factor. ► Lactulose production by the enzyme is the highest among enzymatic syntheses. The conditions for maximum lactulose production from lactose, as a single substrate, by a thermostable recombinant cellobiose-2-epimerase from Caldicellulosiruptor saccharolyticus were determined to be pH 7.5, 80°C, 700gl−1 lactose, and 150Uml−1 of enzyme. Under the conditions, the enzyme produced the two bifidus factors lactulose at 408gl−1 and epilactose at 107gl−1 after 2h. The yields of lactulose and epilactose from lactose and the productivities of lactulose and epilactose were 58%, 15%, 204gl−1h−1, and 54gl−1h−1, respectively. The yield and productivity of both lactulose and epilactose from lactose were 74% and 258gl−1h−1, respectively. The yield, concentration, and productivity of lactulose in the present study are the highest among enzymatic syntheses. This is the first trial of enzymatic synthesis of lactulose using the single substrate lactose.