Highly efficient biosynthesis of α-arbutin from hydroquinone by an amylosucrase from Cellulomonas carboniz. (May 2018) - Yu, Shuhuai
Graphical abstract: Highlights: High molar production yield of α-arbutin is obtained without adding ascorbic acid. The reaction time is short (only 2 h), which saves time. The molar ratio of sucrose over hydroquinone is less (4:1), which saves raw material. The low concentration of hydroquinone is beneficial for the synthesis of α-arbutin. Abstract: Few reports about the biosynthesis of α-arbutin using amylosucrase are available. In this work, an amylosucrase from Cellulomonas carboniz T26, CcAS, was identified for highly efficient synthesis of α-arbutin using 20 mM sucrose and 5 mM hydroquinone as a glucosyl donor and acceptor, respectively. The optimum conditions for transglucosylation are a pH of 7.0 and a temperature of 40 °C. Under these conditions, 40%–44.7% of molar production yield of α-arbutin can be obtained at low concentration of hydroquinone (5 mM) without addition of ascorbic acid after 2 h, which saves time and raw material compared with the reported amylosucrase DGAS. In spite of oxidation of hydroquinone at high concentration of 23.6 mM, 16.1% of molar production yield of α-arbutin is acquired using CcAS without addition of ascorbic acid, while only 1.3% is obtained using DGAS. This work presents that higher molar production yield of α-arbutin at low concentrations of hydroquinone can be obtained using amylosucrase, because hydroquinone at high concentrations is easily oxidized, which inhibits the synthesis of α-arbutin. Simultaneously, CcAS likely further glycosylates the synthesized α-arbutin after a 2-h reaction, which is not reported using DGAS. CcAS exhibits a potential in industrialized application.