Wan Yongqing, Liu Siyuan, Song Yunhao, Tian Ruihua, Wang Ruigang, Duan Kaihong, Mandlaa Mandlaa
College of Life Science, Inner Mongolia Agricultural University, Hohhot, China.
College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot, China.
Front Microbiol. 2024 Dec 4;15:1463645. doi: 10.3389/fmicb.2024.1463645. eCollection 2024.
The enhancement of cellulose degradation is important for improving the quality of corn-stalk silage. However, the rapid drop in pH caused by the propagation of lactic acid bacteria (LAB) can influence the degradation of cellulose by cellulose-degrading microorganisms (CDMs) during the mixed fermentation process of ensilage. In this study, a CDM ( 2-4, BM 2-4) was isolated, and its lyophilization condition was studied. Moreover, a slow-release strategy was developed to delay the release of LAB ( S-1, LP S-1) by embedding technology to provide time for BM 2-4 to degrade cellulose during the corn-stalk ensilage process. The results showed that BM 2-4 had a higher survival rate (89.53%) under the following conditions: cell collection (5,600 r/min in 4.4°C for 9.5-min centrifugation) and lyophilization using cryoprotectants [skim milk (10.4%), peptone (10.4%), and glucose (5.2%)] at -50°C with a vacuum pressure of <10 Pa. Based on the results of the previous study on embedded LP S-1, simultaneous inoculation of embedded LP S-1 and lyophilized BM2-4 at a 2:1 ratio, with an inoculum size of 6% and moisture content of 85%, significantly degraded by 3.8% and increased CP by 3.7% ( < 0.05). This treatment did not significantly influence the final pH of corn-stalk silage ( > 0.05) after 7 days of fermentation.
提高纤维素降解率对于改善玉米秸秆青贮饲料的品质至关重要。然而，在青贮混合发酵过程中，乳酸菌（LAB）繁殖导致的pH值迅速下降会影响纤维素降解微生物（CDM）对纤维素的降解。本研究分离出一种CDM（2-4，BM 2-4），并对其冻干条件进行了研究。此外，通过包埋技术开发了一种缓释策略来延缓LAB（S-1，LP S-1）的释放，以便在玉米秸秆青贮过程中为BM 2-4降解纤维素提供时间。结果表明，BM 2-4在以下条件下具有较高的存活率（89.53%）：细胞收集（4.4℃下5600 r/min离心9.5分钟），以及使用冷冻保护剂[脱脂乳（10.4%）、蛋白胨（10.4%）和葡萄糖（5.2%）]在-50℃、真空压力<10 Pa下进行冻干。基于之前对包埋LP S-1的研究结果，以2:1的比例同时接种包埋LP S-1和冻干BM2-4，接种量为6%，水分含量为85%，纤维素显著降解了3.8%，粗蛋白增加了3.7%（P<0.05）。该处理在发酵7天后对玉米秸秆青贮饲料的最终pH值没有显著影响（P>0.05）。
