柠檬酸发酵过程中酸浓度对柠檬酸发酵的影响

Effect of Citric Acid Concentration on Citric Acid Fermentation

本文发现造成柠檬酸高浓发酵残糖高的主要原因是发酵料液中的糖化酶失活,使液化淀粉糖化不完全。对生产菌株分泌糖化酶性质研究发现,该酶在p H 2.0以下时仍能保留50%以上的酶活性,但对柠檬酸耐受性较差,2%柠檬酸就会对糖化酶活力造成强烈抑制,酶活力损失达90%以上。针对这种情况本文通过在发酵料液中预加商品糖化酶,加快糖化进程,及时完成糖化,解决了柠檬酸高浓发酵残糖高的问题。

In this paper, the reason that high concentrations of sugar were remained in the citric acid fermentation process was found to be glucoamylase deactivation, which led to the incomplete saccharifi cation of liquefi ed starch. The investigation aimed at the glucoamylase secreted by the industrial strain indicated that the glucoamylase still kept above 50% of enzyme activity below p H 2.0. But, its tolerance to citric acid was badly poor, 2% of citric acid would exert strong inhibition on its activity and its activity would decrease to above 90%. In order to solve this problem, the commercial glucoamylase was added into the fermentation broth before the fermentation started, which would accelerate the saccharifi cation. Based on the operation process, high concentration of residual sugar in the citric acid fermentation would be consumed completely.