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

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.