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通过发酵罐批次发酵实验,对C.tropicalis HDY-02发酵木糖合成木糖醇的几个重要发酵参数进行了考察。结果显示,发酵最适温度为35℃,最适发酵pH6.0,最适初始木糖浓度为80 g/L,氧传递系数为KL a 16.5 h-1和18.3 h-1时分别获得最大木糖醇得率为0.73 g/g和最大产率为0.84 g/L·h。因此,为获得更高的木糖醇得率和产率,在发酵过程中采用两阶段的通气策略(0~24 h,KL a为18.3 h-1;24 h之后KL a改为16.5 h-1)。在两阶段通气条件下采用发酵温度35℃,发酵pH6.0,初始木糖浓度80 g/L进行批次发酵,72 h时木糖醇浓度和木糖消耗浓度均达最大值,获得了62.1 g/L木糖醇,0.86 g/L·h产率和0.77 g/g得率。
Several fermentative parameters of xylitol xylose fermentation from C.tropicalis HDY-02 were investigated by fermentor batch fermentation experiments. The results showed that the optimum fermentation temperature was 35 ℃, the optimal fermentation pH6.0, the optimum initial concentration of xylose was 80 g / L, the oxygen transfer coefficient was KL a 16.5 h-1 and 18.3 h-1, respectively, Sugar alcohol yield of 0.73 g / g and maximum yield of 0.84 g / L · h. Therefore, to obtain higher xylitol yield and yield, a two-stage aeration strategy (0-24 h, KL a 18.3 h-1 was used during the fermentation; KL a was changed to 16.5 h- 1). Under the two-stage aeration conditions, the fermentation temperature was 35 ℃, the fermentation pH was 6.0 and the initial xylose concentration was 80 g / L for batch fermentation. The maximum values of xylitol concentration and xylose consumption reached the maximum at 72 h, obtaining 62.1 g / L xylitol, 0.86 g / L · h yield and 0.77 g / g yield.