Li Gen, Yuan Yue, Jin Bowen, Zhang Zhiqiang, Murtaza Bilal, Zhao Hong, Li Xiaoyu, Wang Lili, Xu Yongping
School of Bioengineering, Dalian University of Technology, Dalian, China.
School of Biological Engineering, Dalian Polytechnic University, Dalian, China.
Front Microbiol. 2023 Aug 7;14:1205767. doi: 10.3389/fmicb.2023.1205767. eCollection 2023.
The goal of the research was to find alternative protein sources for animal farming that are efficient and cost-effective. The researchers focused on distillers dried grains with solubles (DDGS), a co-product of bioethanol production that is rich in protein but limited in its use as a feed ingredient due to its high non-starch polysaccharides (NSPs) content, particularly for monogastric animals. The analysis of the E1 genome revealed the presence of 372 genes related to Carbohydrate-Active enzymes (CAZymes), with 98 of them associated with NSPs degrading enzymes that target cellulose, hemicellulose, and pectin. Additionally, although lignin is not an NSP, two lignin-degrading enzymes were also examined because the presence of lignin alongside NSPs can hinder the catalytic effect of enzymes on NSPs. To confirm the catalytic ability of the degrading enzymes, an enzyme activity assay was conducted. The results demonstrated that the endoglucanase activity reached 5.37 U/mL, while beta-glucosidase activity was 4.60 U/mL. The filter paper experiments did not detect any reducing sugars. The xylanase and beta-xylosidase activities were measured at 11.05 and 4.16 U/mL, respectively. Furthermore, the pectate lyase and pectin lyase activities were found to be 8.19 and 2.43 U/mL, respectively. The activities of laccase and MnP were determined as 1.87 and 4.30 U/mL, respectively. The researchers also investigated the effect of E1 on the degradation of NSPs through the solid-state fermentation of DDGS. After 240 h of fermentation, the results showed degradation rates of 11.86% for hemicellulose, 11.53% for cellulose, and 8.78% for lignin. Moreover, the crude protein (CP) content of DDGS increased from 26.59% to 30.59%. In conclusion, this study demonstrated that E1 possesses various potential NSPs degrading enzymes that can effectively eliminate NSPs in feed. This process improves the quality and availability of the feed, which is important for animal farming as it seeks alternative protein sources to replace traditional nutrients.
该研究的目标是为畜牧业找到高效且具成本效益的替代蛋白质来源。研究人员聚焦于玉米酒糟及其可溶物（DDGS），这是生物乙醇生产的一种副产品，富含蛋白质，但因其高非淀粉多糖（NSPs）含量，特别是对单胃动物而言，作为饲料成分的用途有限。对E1基因组的分析揭示了372个与碳水化合物活性酶（CAZymes）相关的基因，其中98个与靶向纤维素、半纤维素和果胶的NSPs降解酶相关。此外，尽管木质素不是NSP，但也检测了两种木质素降解酶，因为木质素与NSPs共存会阻碍酶对NSPs的催化作用。为确认降解酶的催化能力，进行了酶活性测定。结果表明，内切葡聚糖酶活性达到5.37 U/mL，而β-葡萄糖苷酶活性为4.60 U/mL。滤纸实验未检测到任何还原糖。木聚糖酶和β-木糖苷酶活性分别测定为11.05和4.16 U/mL。此外，果胶酸裂解酶和果胶裂解酶活性分别为8.19和2.43 U/mL。漆酶和锰过氧化物酶活性分别测定为1.87和4.30 U/mL。研究人员还通过DDGS的固态发酵研究了E1对NSPs降解的影响。发酵240小时后，结果显示半纤维素降解率为11.86%，纤维素降解率为11.53%，木质素降解率为8.78%。此外，DDGS的粗蛋白（CP）含量从26.59%增加到30.59%。总之，本研究表明E1拥有多种潜在的NSPs降解酶，可有效消除饲料中的NSPs。这一过程提高了饲料的质量和可利用性，这对寻求替代蛋白质来源以取代传统营养物质的畜牧业很重要。
