The Interaction Mechanism Of Microbial Community Structure And Carbon Catabolism In Poultry Manure Aerobic Compost

In this study,livestock manure and plant stalks were used as the main materials.Three groups of aerobic compost were established with defoliation,restaurant-kitchen garbage,and compost compost as regulators and leavening agents.The physicochemical properties in the composting process were examined to study the degradation of carbon.At the same time,a new DNA extraction method was combined with next-generation sequencing technology to analyze the succession of microbial communities during aerobic composting.The purpose was to reveal the interaction mechanism between microbial population structure and carbon metabolism.The main findings are as follows:(1)A high-cost,high-replication and high-efficiency DNA extraction method was established for high humic acid content in compost samples.The method uses 3M chromatography filter paper to adsorb the microorganisms in the compost sample extraction solution.After elution and impurity removal,the cells are pyrolyzed with Chelex-100 resin to collect DNA,and finally the PCR-BRISA fingerprint is used to verify the extracted DNA.The results showed that the correlation coefficient of the DNA extracted from the new method was 0.838 between parallel samples,and the similarity was high.The comparison between the new method and the kit chromatography filter paper,the correlation coefficient was 0.882,indicating that the new method and the kit had similar DNA extraction efficiency.The above results show that the new DNA extraction method has the characteristics of low cost,high repetition and high efficiency,and lays the foundation for high-throughput extraction and community display of compost samples.(2)Comparing the application of next-generation sequencing technology(NGS)in the analysis of compost timing samples.Six selected compost points were selected for DNA extraction,specific amplification,DNA purification,and next-generation sequencing.Comparing the sequencing results of the V3-V4 and V6-V8 hypervariable regions of 16 S rDNA,the results showed that in the microbial community diversity,the V6-V8 region was significantly higher than the V3-V4 region(p=0.025);For the level of information identification,V6-V8 region sequencing information(92% can be identified)is slightly higher than the V3-V4 region(85% can be identified),but the difference is not significant(p=0.063);in terms of bacterial structure,At the levels of classes,orders,families,and genera,the differences between the V3-V4 and V6-V8 regions were not significant.Therefore,the results of the NGS sequencing of the V3-V4 and V6-V8 regions are not significantly different in general.Given that V6-V8 can identify higher microbial diversity and provide more bacterial species information,V6-V8 should be selected.The NGS sequencing method in the district was used to test the community structure of subsequent compost samples.(3)Combining established DNA extraction and NGS community analysis techniques,the carbon characteristics and microbial community changes of the three groups of aerobic compost with added defoliation,food waste,and decomposed compost were analyzed.The results showed that the rate of degradation of total carbon,organic matter,lignin,and alkyl carbon was significantly higher(p<0.05)in the addition of composted compost than in the other two groups,but in water-soluble carbon,humic acid,and cellulose.There was no significant difference in the degradation of the amino and aromatic carbons.Combined with the analysis of macroscopic carbon properties and community structure characteristics,it was found that the respiration rate of cellulose,total carbon,total water-soluble carbon,and CO2 were important composting carbon indicators,affecting the changes of bacterial species of 28%,19%,and 17%,respectively.The transformation of the dominant species from Sinibacillus,Thiopseudomonas to Serpens,Microbacterium,Brachybacterium,Brevibacterium was promoted.In the carbon properties of micro-functional groups,alkyl carbons and alkyl halocarbons indicate the composting process,affecting 36% and 11% of the bacterial species changes,respectively.In summary,the microbial community structure of compost has a significant interaction with carbon degradation.An in-depth study of the interaction mechanism between the two is conducive to revealing the driving mechanism of aerobic composting efficiency and laying the foundation for the separation,identification,and utilization of functional microorganisms.