Discovery of novel alkaline-tolerant xylanases from fecal microbiota of dairy cows
Journal article, 2023

Xylo-oligosaccharides (XOS) are considered as a promising type of prebiotics that can be used in foods, feeds, and healthcare products. Xylanases play a key role in the production of XOS from xylan. In this study, we conducted a metagenomic analysis of the fecal microbiota from dairy cows fed with different types of fodders. Despite the diversity in their diets, the main phyla observed in all fecal microbiota were Firmicutes and Bacteroidetes. At the genus level, one group of dairy cows that were fed probiotic fermented herbal mixture-containing fodders displayed decreased abundance of Methanobrevibacter and increased growth of beneficial Akkermansia bacteria. Additionally, this group exhibited a high microbial richness and diversity. Through our analysis, we obtained a comprehensive dataset comprising over 280,000 carbohydrate-active enzyme genes. Among these, we identified a total of 163 potential xylanase genes and subsequently expressed 34 of them in Escherichia coli. Out of the 34 expressed genes, two alkaline xylanases with excellent temperature stability and pH tolerance were obtained. Notably, CDW-xyl-8 exhibited xylanase activity of 96.1 ± 7.5 U/mg protein, with an optimal working temperature of 55 ℃ and optimal pH of 8.0. CDW-xyl-16 displayed an activity of 427.3 ± 9.1 U/mg protein with an optimal pH of 8.5 and an optimal temperature at 40 ℃. Bioinformatic analyses and structural modeling suggest that CDW-xyl-8 belongs to GH10 family xylanase, and CDW-xyl-16 is a GH11 family xylanase. Both enzymes have the ability to hydrolyze beechwood xylan and produce XOS. In conclusion, this metagenomic study provides valuable insights into the fecal microbiota composition of dairy cows fed different fodder types, revealing main microbial groups and demonstrating the abundance of xylanases. Furthermore, the characterization of two novel xylanases highlights their potential application in XOS production.

Enzyme characterization

Xylo-oligosaccharides

Metagenomics

Dairy cow fecal microbiota

Xylanases

Author

Xiaoling Zhang

Zhengzhou University

Qin Miao

Zhengzhou University

Bingling Tang

Zhengzhou University

Ivan Mijakovic

Chalmers, Life Sciences, Systems and Synthetic Biology

Novo Nordisk Foundation

Xiao Jun Ji

Nanjing Tech University

Lingbo Qu

Zhengzhou University

Yongjun Wei

Zhengzhou University

Biotechnology for Biofuels and Bioproducts

27313654 (eISSN)

Vol. 16 1 182

Subject Categories

Bioprocess Technology

Animal and Dairy Sience

DOI

10.1186/s13068-023-02435-8

PubMed

38012750

More information

Latest update

1/3/2024 9