黑曲霉组成型表面展示南极假丝酵母脂肪酶B及其发酵调控

黑曲霉表面展示南极假丝酵母脂肪酶B(CALB)可有效应用于食品、化妆品、医药等行业。以黑曲霉Aspergillus niger SH-1为宿主细胞构建诱导型糖化酶基因启动子表面展示CALB,在较高浓度葡萄糖碳源的发酵中CALB表达会受到抑制,发酵后期菌体容易出现菌丝断裂和展示酶活力下降等问题。采用组成型3-磷酸甘油醛脱氢酶基因启动子替代诱导型糖化酶基因启动子的细胞表面展示CALB黑曲霉菌株可有效解决上述问题,该菌株不但可以利用葡萄糖,而且还能利用木糖为发酵碳源,以木糖为碳源发酵在144 h展示酶水平达到1 100.28 U/g。文中探讨了甘蔗渣水解液发酵生产黑曲霉表面展示CALB,初步达到预期的结果,为甘蔗渣的综合利用提供了新途径。

Constitutive display of Candida antarctica lipase B on the cell surface of Aspergillus niger and regulation of its fermentation

Displaying Candida antarctica lipase B (CALB) on the cell surface of Aspergillus niger is effectively applied for the industries of food, cosmetics, pharmaceutical and so on. Displaying CALB using induced promoter of glucoamylase on the cell surface of A. niger SH-1 has some problems such as inhibiting its expression under high concentration of glucose, mycelium cleavage and decreasing enzyme activity in the later period of fermentation process. Displaying CALB manipulated by constitutive promoter from glyceraldehyde-3-phosphate dehydrogenase instead of glucoamylase on the cell surface of A. niger SH-1, called AN-GpdA, could solve the above problems effectively. Furthermore, it can not only use glucose, but also xylose as a sole carbon source. Enzyme activity of AN-GpdA using xylose for fermentation reached 1 100.28 U/g of dry cell. We also used lignocellulose such as the hydrolysate of bagasse for fermentation with good performance. The result would provide a novel strategy for the utilization of bagasse.