Nucleus of Research in Biological Sciences, Federal University of Ouro Preto, Ouro Preto, Brazil.
Department of Biochemistry and Molecular Biology, Federal University of Viçosa, Viçosa, Brazil.
J Sci Food Agric. 2019 Jan 30;99(2):741-747. doi: 10.1002/jsfa.9242. Epub 2018 Aug 28.
Endo-1,4-β-xylanases have marked hydrolytic activity towards arabinoxylans. Xylanases (xynA) produced by the anaerobic fungus Orpinomyces sp. strain PC-2 have been shown to be superior in specific activity, which strongly suggests their applicability in the bakery industry for the processing of whole-wheat flour containing xylans. In the present study, two xylanases from this source, the small wild-type xylanase SWT and the small mutant xylanase SM2 (V108A, A199T), were expressed in Escherichia coli, purified, characterized, tested for their ability to hydrolyze whole-wheat flour and applied in dough processing.
Both purified SM2 and SWT showed high specific activity against oat spelt xylan and wheat arabinoxylan, exhibiting maximum activity at pH 3-7 and 60 °C. SM2 was more thermostable than SWT, which suggests that the mutations enhanced its stability. Both SWT and SM2 were able to hydrolyze whole-wheat flour, and evaluation of their applicability in dough processing by the sponge method indicated that use of these enzymes increased dough volume by 60% and reduced texture hardness by more than 50%, while gumminess and chewiness were reduced by 40%.
The recombinant xylanases showed potential for application in bakery processing and can improve techno-functional properties in sponges. © 2018 Society of Chemical Industry.
内切-1,4-β-木聚糖酶对阿拉伯木聚糖具有显著的水解活性。已证明厌氧真菌 Orpinomyces sp. 菌株 PC-2 产生的木聚糖酶（xynA）在比活性方面具有优势，这强烈表明它们在含有木聚糖的全麦面粉加工的烘焙工业中的适用性。在本研究中，来自该来源的两种木聚糖酶，即小野生型木聚糖酶 SWT 和小突变体木聚糖酶 SM2（V108A、A199T），在大肠杆菌中表达、纯化、表征、测试其水解全麦面粉的能力并应用于面团加工。
两种纯化的 SM2 和 SWT 对燕麦黑麦木聚糖和小麦阿拉伯木聚糖均表现出高比活性，在 pH3-7 和 60°C 时表现出最大活性。SM2 比 SWT 更耐热，这表明突变增强了其稳定性。SWT 和 SM2 均能水解全麦面粉，通过海绵法评估其在面团加工中的适用性表明，使用这些酶可使面团体积增加 60%，质地硬度降低 50%以上，而胶粘性和咀嚼性降低 40%。
重组木聚糖酶在烘焙加工中具有应用潜力，并能改善海绵的工艺功能特性。© 2018 化学工业协会。
