镰刀菌Fo47来源木聚糖酶的异源表达、酶学性质及其对全麦面包品质的影响

Xylanase from Fusarium oxysporum Fo47:Expression,Characterization and Application in Whole-wheat Bread Making

为开发新型面粉改良酶制剂,该研究对通过基因组挖掘手段筛选出的一种新型木聚糖酶——镰刀菌Fo47来源木聚糖酶(Fusarium oxysporum Fo47 xylanase,FXYL),利用毕赤酵母X33首次对其进行异源表达,分析重组FXYL的酶学性质,并初步探究重组FXYL对全麦面包品质的影响。结果表明,摇瓶发酵144 h后,重组毕赤酵母发酵上清液木聚糖酶酶活力为779.64 U/mL;经过Ni-NTA柱层析纯化后,重组FXYL的比酶活为764.33 U/mg;酶学性质研究表明,重组FXYL最适反应pH值为5.0,最适反应温度为45℃,在中温(<40℃)和pH 5.5~10.0表现出较好的稳定性。重组FXYL的酶学性质较适合面团发酵的偏酸环境;添加重组FXYL能够显著提高全麦面包的比容和弹性,降低全麦面包的硬度和咀嚼性,有望发展为一种新型面粉改良剂。

This study aimed to develop a new biological flour improver.A novel xylanase from Fusarium oxysporum Fo47(FXYL)screened out through genome mining approach was expressed in Pichia pastoris X33.The enzymatic properties of the recombinant FXYL were characterized,and the effect on the quality of whole-wheat bread was explored.The results showed that the xylanase activity of the supernatant was 779.64 U/mL when the recombinant strain was cultured in shake flask for 144 h,and the specific activity of the recombinant FXYL purified by Ni-NTA affinity chromatography was 764.33 U/mg.The enzyme showed the best properties at pH 5.0 and 45℃.The recombinant FXYL presented good thermostability and pH stability in the case of temperature<40℃and pH 5.5-10.0 and was suitable for the weak acid environment of dough fermentation.The application of recombinant FXYL significantly increased the specific volume and springiness and decreased the hardness and chewiness of whole-wheat bread.Therefore,the recombinant FXYL is expected to be developed into a new flour improver.