双孢蘑菇栽培基质二次发酵过程细菌结构变化趋势研究

Research on Trend of Microbial Structure Changes during the Secondary Fermentation Process of Agaricus bisporus Cultivation Substrate

【目的】为明确双孢蘑菇栽培基质二次发酵过程中细菌结构动态变化趋势。【方法】利用高通量测序技术测定了双孢蘑菇栽培基质二次发酵过程细菌群落变化及其与环境因子的关系。【结果】基质中共有细菌物种OTU数目1128个,包含26个门、66个纲、164个目、257个科、454个属和687个种。细菌种群结构在发酵过程中发生显著变化,发酵初始优势细菌属为尿素芽胞杆菌属、芽胞杆菌属、赖氨酸芽胞杆菌属、拉梅尔芽胞杆菌属及库特氏菌属,发酵末期优势细菌属则为norank_f__Limnochordaceae、氢孢菌属、嗜热双孢菌属和盐孢菌属。发酵中期和发酵末期细菌组成结构相似,与发酵前期呈显著差异。冗余分析显示发酵过程中细菌群落球形杆菌属和特吕珀菌属与氨气浓度呈正相关,球形杆菌属、热多孢菌属和norank_f_Steroidobacteraceae与发酵温度呈正相关,而库特氏菌属与发酵温度呈显著负相关。【结论】基质经过二次发酵可有效降低了有害细菌的丰度,释放氨气浓度可作为二次发酵终点判断指标之一。

【Objective】To clarify the effect of dynamic change of bacteria structure on substrate fermentation during the secondary fermentation process of Agaricus bisporus cultivation substrate.【Method】The high-throughput sequencing technology was used to determine the changes in bacterial community during the secondary fermentation process of Agaricus bisporus cultivation substrate and its relationship with environmental factors.【Result】A total of1128 bacterial operational taxonomic unit(OTU)were detected,including 26 phyla,66 classes,164 orders,257 families,454 genera,and 687 species.The bacterial species structure changed significantly during the fermentation process.At the initial stage of fermentation,the dominant bacterial genera are Ureibacillus,Bacillus.ssp,Lysinibacillus,Rummeliibacillus and Kurthia bacteria.At the end of fermentation,the dominant bacterial genera are norank_f_Lemnochordaceae,Hydrogenispora,Thermophilic Bacillus,and Salinispora.The bacterial species composition was relatively similar at the middle and late stages of fermentation,and was significantly distinguished from that before fermentation.Redundancy analysis showed that the bacterial community was a positive correlation between the genera of Staphylococcus and Truepera and NH_3 concentration.The genera of Staphylococcus,Thermospora,and norank_f_Steroidobactereae were positively correlated with fermentation temperature,while the genusof Kurtosporawas significantly negatively correlated with fermentation temperature.【Conclusion】After the secondary fermentation,the abundance of harmful bacteria effectively was reduced and NH_3 emissions could be regard as the endpoint of fermentation in the substrate.