柠檬酸发酵过程中黑曲霉α-葡萄糖苷酶和糖化酶变化的研究  

Changes of α-glucosidase and glucoamylase from Aspergillus niger in citric acid fermentation

作　　者：杨赢[1] 王德培[1,2] 高年发[1,2] 

机构地区：[1]天津科技大学生物工程学院,天津300457 [2]工业微生物教育部重点实验室,天津300457

出　　处：《中国酿造》2013年第1期22-24,共3页China Brewing

基　　金：科技部高科技发展研究计划‘863计划’项目(2011AA02A205)

摘　　要：以目前柠檬酸生产菌为出发菌株,进行N+注入诱变得到一株柠檬酸高产菌株黑曲霉LD20,将其在500m3发酵罐上进行发酵,分别对发酵过程中α-葡萄糖苷酶、糖化酶、总糖、总酸、还原糖、葡萄糖和pH进行了跟踪测定,结果表明糖化酶GA在20h达到最高酶活895.16U/mL,α-葡萄糖苷酶TGA在24h达到最高酶活322.52U/mL,在整个发酵过程中GA的平均酶活力是TGA的2.9倍,说明在柠檬酸发酵过程中,发酵液的糖化作用主要依赖于GA;在柠檬酸发酵后期TGA比GA对酸有更强的耐受性,主要起到转苷作用,将发酵液中的还原糖转化为非发酵性的糖类,从而生成不能被黑曲霉所利用的残糖。A high citric acid-producing Aspergillus niger mutant named LD20 was developed by N＋ ion implantation fIom an industrial strain. The α-glucosidase, glucoamylase, total sugars, total acids, reducing sugars, glucose and pH was measured during citric acid fermentation of A. niger LD20in 500m3 fermentor. The results showed that the maximum activity of glucoamylase was 895.16U/ml at 20h, while the maximum activity of ot-glucosidase was 322.52U/ml at 24h. The average enzyme activity of glucoamylase was 2.9 times of oL-glucosidase. It was indicated that in citric acid fermentation, the saccharification of carbon sources was mainly catalyzed by glucoamylase. At the final stage of fermentation,α-lucosidase was more acid-tolerant than glucoamylase, and could catalyze reducing sugars into non-fermentable sugars by transglycosidation reaction. The non-fer- mentable sugars could not be used by the A. niger and would be left as residue sugars.

关 键 词：黑曲霉 柠檬酸 Α-葡萄糖苷酶 糖化酶 

分 类 号：TQ921[轻工技术与工程—发酵工程]