Differences in succession of bacterial communities during co-cultivation of corn straw with different soils

Abstract

Managing carbon inputs from straw can pave the way towards carbon neutrality and climate change mitigation. Straw decomposition by cooperative microbial actions is an important process of carbon cycling in nature, and in this process, microbial communities are constantly in succession. Soil is rich in microorganisms and can be a source of microbial for straw degradation. In this study, corn straw was mixed with different soil types and incubated in conical flasks for 70 days. Bacterial diversity and community structure were determined using 16S rRNA sequencing. Then, the effects of physicochemical parameters and enzyme activities on the composition of bacterial communities at different stages were evaluated. The results showed that bacterial diversity decreased during co-cultivation. The differences in bacterial communities between all treatments were greater in the later stages, with Pseudomonadota, Actinomycetota, and Bacillota as the major phyla. Among them, the biomarkers at different times for different treatments included Sphingomonas, Mycobacterium, Oceanobacillus, Streptomyces, Pseudomonas, Flavobacterium, and Saccharomonospora. All of them showed cellulose degradation capacity; thus, the organic matter gradually decreased during the co-cultivation. Canonical correspondence analysis (CCA) showed that pH, organic matter (OM), electrical conductivity (EC), cellulase, β-glucosidase, and filter paper (FPase) activities had a significant effect on bacterial communities at different stages. Our findings suggested that soil microbial communities can be an effective source of cellulose-degrading microorganisms, and corn straw co-cultivation with different soil types increased the abundance of cellulose-degrading bacteria, which provides the theoretical basis for efficient cellulose-degrading agent screening.