复合芽孢杆菌对鲫鱼养殖水体水质及细菌群落结构的影响

Effect of Bacillus Complex on Water Quality and Bacterial Community Structure of Carassius aumtus Culture Water

为寻找对养殖水体降解效果更好的菌株,以巨大芽孢杆菌(Bacillus megaterium,简称A0)、凝结芽孢杆菌(Bacillus coagulans,简称BC)、枯草芽孢杆菌(Bacillus subtilis,简称BS)为研究对象,探究了复合芽孢杆菌A0+BC、A0+BS对鲫鱼(Carassius aumtus)养殖水体营养盐N、P的改善效果,并采用高通量测序分析细菌群落结构变化,结果显示:复合芽孢杆菌A0+BS对NH4^+-N、NO2^--N、NO3^--N、TP降解效果最显著,降解率分别达46.3%、76.3%、35.6%、80.3%;复合芽孢杆菌A0+BC对TP没有降解效果。7 d水样的高通量测序结果与对照(CK)相比,处理组微生物多样性增加,且A0+BS组微生物多样性最高;处理组厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)减少,变形菌门(Proteobacteria)、放线细菌门(Actinobacteria)增加,且A0+BS组放线细菌门相对丰度最高。对照组优势菌主要为赖氨酸芽孢杆菌属(Lysinibacillus)、土壤芽孢杆菌属(Solibacillus)、血液杆菌属(Haematobacter);处理组优势菌丛毛单胞菌属(Comamonas)为异养硝化-好氧反硝化菌;A0+BC组其他优势菌不动杆菌属(Acinetobacter)、假单胞菌属(Pseudomonas)均为致病菌;A0+BS组其他优势菌硝化杆菌属(Bosea)、Dokdonella属均为脱氮菌。复合芽孢杆菌A0+BS脱氮除磷效果最佳,且水体TP、NH 4+-N浓度符合GB 3838—2002《地表水环境质量标准》的Ⅲ级标准;投加芽孢杆菌对养殖水体微生物群落结构进行调控,养殖水体水质得到改善。

Bacillus megaterium(A0),Bacillus coagulans(BC),Bacillus subtilis(BS)were compared for their degradation effects on aquaculture water.The effects of the combination of A0+BC and A0+BS on N and P concentrations and bacterial community structure in carp culture water were studied.The results show that the degradation effects of A0+BS on NH4^+-N,NO2^--N,NO3^--N and TP were the most significant,and the degradation rates were 46.3%,76.3%,35.6%and 80.3%,respectively.The concentration of TP and NH 4+-N conformed to the 3rd grade of National Surface Water Environmental Quality Standard.The concentration of TP in group A0+BC was always higher than that in CK.This result suggests that the combination of A0 and BS had synergistic effect on the removal of NH4^+-N,NO2^--N,NO3^--N,TP,and previous studies show that Bacillus coagulans had no degradation effect on TP.The microbial communities were profiled by high-throughput sequencing of the V3-V4 hypervariable region of 16S rRNA gene using the MiSeq Illumina sequencing platform.The results show that the microbial community diversity in the A0+BS group was the highest.In addition,adding Bacillus complex in aquaculture water reduced the number of Bacteroidets,increased Proteobacteria and Actinobacteria.The relative abundance of Actinobacteria in the A0+BS group was the highest.Lysinibacillus,Solibacillus and Haematobacter were mainly dominant bacterias in the CK group.The dominant strain was Comamonas belonging to heterotrophic nitrification-aerobic denitrifying bacteria in A0+BC and A0+BS group.Other dominant bacteria in A0+BC group Acinetobacter and Pseudomonas were pathogenic bacteria.In A0+BS group dominant bacteria Bosea and Dokdonella were denitrifying bacteria.A0+BS regulated the microbial community structure in the aquaculture water,which improved the water quality of the aquaculture water.