嗜麦芽黄单胞菌催化生产α－熊果苷的菌种选育

利用硫酸二乙酯和紫外线对嗜麦芽黄单胞菌（Xanthomonas maltophilia ）复合诱变，初筛和复筛后，得到了转化率高且遗传性能稳定的α－熊果苷生产菌株BT-112。该菌株在以蔗糖为碳源、发酵液初始pH为7.5，温度为28℃，摇床转速为150r/min及发酵时间为48h的条件下,对苯二酚转化为α－熊果苷的转化率可达93.2％，比出发菌株转化率（73.0％）提高了27.7%。纯化产物经NMR鉴定，与标准品对比，确定为α－熊果苷。

Mutation breeeding of Xanthomonas maltophilia for the synthesis of α-arbutin

A Xanthomonas maltophilia strain was mutated using diethyl sulfate (DES) and UV irradiation. The BT-112 strain was found to produce α－arbutin with high conversion efficiency and could be recycled without loss of activity. . The optimum fermentation conditions were found to be sucrose as the carbon source, initial pH 7.5, fermentation temperature 28 ^oC, shaker speed 150 r/min, and fermentation time 48 h. Under these conditions the conversion of hydroquinone to α－arbutin reached 93.2%, which was an increase of 27.7% over that obtained with the starting strain (70.3%). The ¹³C-NMR and ¹H-NMR spectra of the purified product were identical to those of an authentic sample of α-arbutin.