低温秸秆降解复合菌系的功能及组成稳定性

Functions and composition stability of straw-degrading microbial consortia under low temperatures

摘要:

【背景】木质纤维素微生物降解是促进其分解转化的有效措施之一。【目的】探明复合菌系的秸秆降解效率，并评价其对自然碳源的适应性和稳定性。【方法】以团队前期筛选获得的复合菌系M1、M2、M14、M36和M44为试验材料，以灭菌(S)玉米秸秆和未灭菌(NS)玉米秸秆作为碳源进行限制性继代培养，探明复合菌系的秸秆降解效率，揭示其对自然碳源的适应性和稳定性。【结果】M1、M2、M14、M36和M44在不同培养代数间玉米秸秆降解率、酶活性均无显著差异，可保持稳定的秸秆降解效率，在未灭菌(NS)秸秆处理条件下秸秆降解率分别为30.99%、33.41%、33.97%、31.76%和35.05%，均显著高于灭菌(S)秸秆处理。各复合菌系的物种组成分析表明，随着继代培养，不同秸秆条件下各复合菌系丰富度和多样性趋于一致，厚壁菌门(Firmicutes)和毛球菌属(Trichococcus)相对丰度在秸秆未灭菌(NS)处理下显著高于秸秆灭菌(S)处理，分别提高了31.5%、48.97%、41.95%、2.64%、67.41%和27.95%、41.71%、33.63%、15.75%、63.22%。【结论】复合菌系随继代表现出良好的稳定性，对未灭菌秸秆表现出良好的适应性，具有潜在优势和利用价值。

Abstract:

[Background] Microbial degradation is an effective measure to promote the decomposition and transformation of lignocellulose. [Objective]To investigate the degradation efficiency of straw and evaluate its adaptability and stability to natural carbon sources. [Methods] To study the straw degradation efficiency of the microbial consortia M1, M2, M14, M36, and M44 screened out in the previous study and evaluate their adaptability and stability when being cultured with natural carbon sources. We used sterilized (S) corn stover and non-sterilized (NS) corn stover as the carbon sources for restrictive passage of M1, M2, M14, M36, and M44. [Results] Neither the degradation rate of corn stover nor the enzyme activity had significant difference across different passages, which indicated that the microbial consortia M1, M2, M14, M36, and M44 could maintain stable straw degradation efficiency. M1, M2, M14, M36, and M44 in the NS group exhibited the corn stover degradation rates of 30.99%, 33.41%, 33.97%, 31.76%, and 35.05%, respectively, which were higher than those in the S group. The richness and diversity of microbial consortia cultured with different carbon sources became similar as the passage continued. Specifically, the relative abundance of Firmicutes and Trichococcus in M1, M2, M14, M36, and M44 in the NS group was 31.5%, 48.97%, 41.95%, 2.64%, 67.41% and 27.95%, 41.71%, 33.63%, 15.75%, 63.22%, respectively, higher than that in the S group. [Conclusion] The microbial consortia demonstrated robust stability and adaptability when being cultured with non-sterilized corn stover, showcasing promising advantages and potential utility.