Lactulose production from lactose by recombinant cellobiose 2‐epimerase in permeabilised Escherichia coli cells |
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| Authors: | Mingming Wang Ruijin Yang Xiao Hua Qiuyun Shen Wenbin Zhang Wei Zhao |
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| Affiliation: | 1. State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China;2. School of Food Science and Technology, Jiangnan University, Wuxi, China |
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| Abstract: | Caldicellulosiruptor saccharolyticus cellobiose 2‐epimerase (CsCE) catalyses the single substrate lactose into lactulose and is the most efficient enzyme ever found for the enzymatic synthesis of lactulose. Ethanol‐permeabilised Escherichia coli cells containing CsCE were used as biocatalysts for lactulose production. The reaction conditions for maximum lactulose production were optimised to be 600 g L?1 lactose, pH 7.5, 80 °C and 12.5 U mL?1 of whole‐cell biocatalyst. After incubated at Na2HPO4–NaH2PO4 buffer for 2 h, approximately 390.59 g L?1 lactulose was obtained with a conversion yield of 65.1%. The lowest production and conversion yield of epilactose were also found in Na2HPO4–NaH2PO4 buffer with a final concentration of 11.7 g L?1 and a conversion yield <2%. The results represent a promising technology to attain high production and conversion yield of lactulose with a high purity on industrial scale. |
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| Keywords: | Cellobiose 2‐epimerase lactose lactulose optimum reaction conditions permeabilised Escherichia coli cells |
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