Li Yangyang, Li Cen, Muhammad Aqeel Sahibzada, Wang Yachan, Zhang Quan, Ma Jianing, Zhou Jingwen, Li Jianghua, Du Guocheng, Liu Song
National Engineering Research Center for Cereal Fermentation and Food Biomanufacturing, Jiangnan University, Wuxi 214122, China; Science Center for Future Foods, Jiangnan University, Wuxi 214122, China; School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China.
Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region (Ministry of Education), College of Life Sciences/Institute of Agro-bioengineering, Guizhou University, Guiyang 550025, China.
Bioresour Technol. 2023 Jun;377:128962. doi: 10.1016/j.biortech.2023.128962. Epub 2023 Mar 24.
The high cost and process complexity limit the enzymatic extraction of β-glucan. In this study, β-glucan was extracted from oat bran in a two-step enzymatic pathway using a recombinant strain of Aspergillus niger AG11 overexpressing the endogenous xylanase (xynA) and amylolytic enzyme. First, co-optimization of promoter and signal peptide and a fusion of glucoamylase (glaA) fragment were integrated into the β-glucosidase (bgl) locus to improve xynA expression. Then, the optimized expression cassette was simultaneously integrated into bgl, α-amylase amyA, and acid α-amylase ammA loci, yielding the Rbya with 3,650-fold and 31.2% increase in xynA and amylolytic enzyme activity than the wild-type strain, respectively. Finally, Rbya's supernatants at 72 h (rich in xynA and amylolytic enzyme) and 10 d (rich in proteases) were used to decompose xylan/starch and proteins in oat bran, respectively, to obtain 85.1% pure β-glucan. Rbya could be a robust candidate for the cost-effective extraction of β-glucan.
