生物炭对猪粪堆肥过程中细菌群落结构的影响

Effect of biochar on bacteria community structure of pig manure composting

摘要:

【背景】细菌群落多样性影响堆肥过程，生物炭影响细菌的生长，但生物炭对猪粪堆肥细菌群落结构的影响尚未见报道。【目的】根据细菌群落结构和堆肥温度的变化规律，添加适量的生物炭到猪粪堆肥，以提高堆肥主要细菌的占比和堆肥效率，为推广生物炭和猪粪堆肥的联合应用提供参考。【方法】设计0%、3%、6%和9%的生物炭添加量，在堆肥的高温期和温度稳定期分别取样，总共8个样品。根据Illumina MiSeq对细菌16S rRNA基因的高通量测序结果，分析生物炭添加量和堆肥温度对猪粪堆肥细菌群落结构的影响。【结果】在细菌门水平上，猪粪堆肥主要的细菌有Proteobacteria、Actinobacteria、Bacteroidetes、Chloroflexi、Gemmatimonadetes、Firmicutes、Acidobacteria和Deinococcus-Thermus；在细菌属水平上，猪粪堆肥主要的细菌有Chryseolinea、Subgroup_6_norank、Steroidobacter、Anaerolineaceae、Nonomuraea、Longispora、Bacillus、Sporacetigenium、Luteimonas、Phyllobacteriaceae、Truepera、Rhodothermacea和Aquamicrobium。生物炭添加量对猪粪堆肥主要细菌的生长既有促进作用，也有抑制作用。随着生物炭添加量的增加，Bacillus、Streptomyces、Rhodothermaceae和Firmicutes的丰度随之增加，而Chryseolinea、Longispora和Steroidobacter的丰度却随之减少。Firmicutes、Bacillus和Streptomyces的丰度在堆肥高温期要大于堆肥温度稳定期，而Chloroflexi、Anaerolineaceae和Longispora则相反。猪粪堆肥高温期的细菌多样性要明显大于堆肥温度稳定期。堆肥高温期的细菌群落达到70个，远多于堆肥温度稳定期的15个；其中对猪粪堆肥起主要作用的细菌，堆肥高温期时达到7个(Rhizobiales、Incertae_Sedis、Proteobacteria、Alphaproteobacteria、Xanthomonadales、Gammaproteobacteria 和Steroidobacter)，而堆肥温度稳定期只有3个(Micromonosporales、Longispora和Micromonosporaceae)。猪粪堆肥添加生物碳后，环境因子(电导率、含水量、温度和pH)对堆肥主要的细菌不能产生显著的影响。β-Proteobacteria、Rhodothermaceae、Phyllobacteriaceae和Bacterium是含水量、温度和pH影响最大的细菌。【结论】生物碳添加量和堆肥温度能改变猪粪堆肥的细菌群落结构，在猪粪堆肥高温期能显著增加细菌的数量和多样性。猪粪堆肥的电导率、含水率、温度和pH能影响堆肥细菌的生长，但对堆肥主要细菌的影响不显著。

Abstract:

[Background] The bacterial community diversity affected the composting process and biochar affected the growth of bacteria, but the effect of biochar on the bacterial community structure of pig manure composting has not been reported yet. [Objective] According to the variation of bacterial community structure and composting temperature, adequate content of biochar was added to pig manure composting to improve the proportion of major bacteria and composting efficiency of pig manure composting, so as to provide reference for the joint application of biochar and pig manure composting. [Methods] The biochar content of 0%, 3%, 6% and 9% was set, and four levels of biochar were selected in the high-temperature period and the stable-temperature period of composting process, respectively. According to the Illumina MiSeq’s high-throughput sequencing results of bacterial 16S rRNA gene, the effects of biochar content and composting temperature on bacterial community structure of pig manure composting were analyzed. [Results] At the phylum level, the major bacteria with the highest abundance in pig manure composting were Proteobacteria, Actinobacteria, Bacteroidetes, Chloroflexi, Gemmatimonadetes, Firmicutes, Acidobacteria and Deinococcus-Thermus. At the genus level, the major bacteria with the highest abundance in pig manure composting were Chryseolinea, Subgroup_6_norank, Steroidobacter, Anaerolineaceae, Nonomuraea, Longispora, Bacillus, Sporacetigenium, Luteimonas, Phyllobacteriaceae, Truepera, Rhodothermaceae and Aquamicrobium. The change of biochar content could promote or inhibit the growth of major bacteria in pig manure composting. As the content of biochar increased, the abundance of Bacillus, Streptomyces, Rhodothermaceae and Firmicutes increased, whereas the abundance of Chryseolinea, Longispora and Steroidobacter decreased. At the high-temperature composting period, the abundance of Firmicutes, Bacillus and Streptomyces was greater than that of the stable-temperature composting period; while Chloroflexi, Anaerolineaceae and Longispora were opposite. The number of bacterial community in high-temperature composting period was up to seventy, significantly greater than stable-temperature composting period of fifteen. Among them, the number of bacteria played a major role in pig manure composting was up to seven (Rhizobiales, Incertae_Sedis, Proteobacteria, Alphaproteobacteria, Xanthomonadales, Gammaproteobacteria and Steroidobacter) in the high-temperature period, while only three (Micromonosporales, Longispora and Micromonosporaceae) were found in the stable-temperature period. The bacterial diversity of pig manure composting in high-temperature period was significantly higher than that of stable-temperature period. After adding biochar to pig manure composting, environmental factors (electrical conductivity, water content, temperature and pH) had no significant effect on the major bacteria of pig manure composting. β-Proteobacteria, Rhodothermaceae, Phyllobacteriaceae and Bacterium were significantly affected by the water content, temperature and pH. [Conclusion] The content of biochar and composting temperature could change the bacterial community structure of pig manure composting, and significantly increase the number and diversity of bacteria in pig manure composting at the high-temperature period. The electrical conductivity, water content, temperature and pH of pig manure composting could affect the growth of composting bacteria, but the effect on the major bacteria with the highest abundance in pig manure composting was not significant.