1
|
Effect of Fibrolytic Enzymes, Cellulolytic Fungi and Lactic Acid Bacteria on Fermentation Characteristics, Structural Carbohydrate Composition and In Vitro Digestibility of Rice Straw Silage. FERMENTATION-BASEL 2022. [DOI: 10.3390/fermentation8120709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This study aimed to investigate the effect of fibrolytic enzymes, cellulolytic fungi and lactic acid bacteria on the fermentation quality, structural carbohydrate composition and in vitro digestibility of rice straw silage. This experiment followed a completely randomised block design; four treatments were designed: (1) distilled water (control, CON); (2) fibrolytic enzymes (2.0 g/kg fresh weight (FW), E); (3) Trichoderma reesei (4400 U/kg FW, F); (4) Enterococcus faecium Y83 (1 × 106 cfu/g FW, Y83). All additives were diluted with distilled water and sprayed onto the rice straw (20 mL/kg FW). The rice straw was placed into a laboratory silo (10 L) after uniformly mixing and stored at ambient temperature (17–22 °C) ensiling for 3, 7, 14, 30 and 60 days. The fermentation quality in treated silages was improved compared to the CON, as indicated by lower pH, propionic acid, acetic acid and ammonia nitrogen (NH3-N) contents. Furthermore, Y83 had the lowest (p < 0.05) pH and highest (p < 0.05) lactic acid content after 60 days of ensiling. Y83 significantly (p < 0.05) decreased the neutral detergent fibre content compared with CON, E and F. In addition, E and Y83 had significantly (p < 0.05) higher in vitro dry matter digestibility and in vitro neutral detergent fibre digestibility than CON and F. Overall, Y83 can be used as a promising inoculant for improving the fermentation quality of rice straw silage.
Collapse
|
2
|
Dong R, Liu X, Wang Y, Qin X, Wang X, Zhang H, Wang Y, Luo H, Yao B, Bai Y, Tu T. Fusion of a proline-rich oligopeptide to the C-terminus of a ruminal xylanase improves catalytic efficiency. Bioengineered 2022; 13:10482-10492. [PMID: 35441569 PMCID: PMC9161913 DOI: 10.1080/21655979.2022.2061290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Xylanases are widely used in the degradation of lignocellulose and are important industrial enzymes. Therefore, increasing the catalytic activity of xylanases can improve their efficiency and performance. In this study, we introduced the C-terminal proline-rich oligopeptide of the rumen-derived XynA into XylR, a GH10 family xylanase. The optimum temperature and pH of the fused enzyme (XylR-Fu) were consistent with those of XylR; however, its catalytic efficiency was 2.48-fold higher than that of XylR. Although the proline-rich oligopeptide did not change the enzyme hydrolysis mode, the amount of oligosaccharides released from beechwood xylan by XylR-Fu was 17% higher than that released by XylR. This increase may be due to the abundance of proline in the oligopeptide, which plays an important role in substrate binding. Furthermore, circular dichroism analysis indicated that the proline-rich oligopeptide might increase the rigidity of the overall structure, thereby enhancing the affinity to the substrate and catalytic activity of the enzyme. Our study shows that the proline-rich oligopeptide enhances the catalytic efficiency of GH10 xylanases and provides a better understanding of the C-terminal oligopeptide-function relationships. This knowledge can guide the rational design of GH10 xylanases to improve their catalytic activity and provides clues for further applications of xylanases in industry.
Collapse
Affiliation(s)
- Ruyue Dong
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaoqing Liu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yaru Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xing Qin
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Xiaolu Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Honglian Zhang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yuan Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huiying Luo
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yingguo Bai
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Tao Tu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| |
Collapse
|