Ma Linxiong, Li Junfeng, Zhao Wanyu, Wang Jingyu, Li Yanwen, Xiong Yueying, He Yongchao, Chu Xiaohui, Liu Qinhua
Yunnan Provincial Key Laboratory of Animal Nutrition and Feed, Department of Pratacultural Science, Faculty of Animal Science and Technology, Yunnan Agricultural University, Kunming, China.
Institute of Ensiling and Processing of Grass, College of Agro-Grassland Science, Nanjing Agricultural University, Nanjing, China.
Front Microbiol. 2025 Apr 15;16:1566973. doi: 10.3389/fmicb.2025.1566973. eCollection 2025.
Using cellulase to convert alfalfa lignocellulose into lactic acid (LA) is useful in low-temperature seasons to improve fermentation quality, but it is still unknown which specific cellulase component synergizes with lactic acid bacteria (LAB) to promote LA fermentation. This study aimed to clarify the key cellulase components that synergized with LAB when converting alfalfa lignocellulose into LA during ensiling from late fall to winter (3-20°C) over 140 days. Seven combinations of cellulase component gene-engineered (MG1363), cellulase (EN), and a combination of and cellulase (LPEN) were used as parallel treatments, with a control (CON) without treatment also used. EN degraded lignocellulose best. The pH value in the channel of converting sugars into LA was the key limiting factor for lignocellulose saccharification in LPEN. The optimal combination resulted in the fewest disaccharides (1.02 g/kg DM) and the highest conversion of water-soluble carbohydrates (WSC) to LA, up to 170%. It increased LA content to 80.0 g/kg DM maximally, since cellobiohydrolase better cooperated with MG1363 to ferment lignocellulose into LA than endoglucanase and -glucosidase. Strong LA production was achieved by clarifying key cellulase components with cellulase component gene-engineered LAB.
在低温季节使用纤维素酶将苜蓿木质纤维素转化为乳酸（LA）有助于提高发酵品质，但仍不清楚哪种特定的纤维素酶组分与乳酸菌（LAB）协同作用以促进LA发酵。本研究旨在阐明在深秋至冬季（3 - 20°C）长达140天的青贮过程中，将苜蓿木质纤维素转化为LA时与LAB协同作用的关键纤维素酶组分。使用纤维素酶组分基因工程菌（MG1363）、纤维素酶（EN）以及二者组合（LPEN）的七种组合作为平行处理，同时设置未处理的对照（CON）。EN对木质纤维素的降解效果最佳。在LPEN中，糖转化为LA途径中的pH值是木质纤维素糖化的关键限制因素。最佳组合产生的二糖最少（1.02 g/kg DM），水溶性碳水化合物（WSC）到LA的转化率最高，可达170%。由于纤维二糖水解酶比内切葡聚糖酶和β-葡萄糖苷酶更能与MG1363协同作用将木质纤维素发酵为LA，其最大可将LA含量提高到80.0 g/kg DM。通过用纤维素酶组分基因工程LAB阐明关键纤维素酶组分实现了高效LA生产。
