以聚羟基丁酸戊酸共聚酯为碳源去除循环水养殖系统的硝酸盐及生物膜中微生物群落动态

Nitrate removal from recirculating aquaculture system using polyhydroxybutyrate-co-hydroxyvalerate as carbon source

摘要:

摘要:【目的】利用聚羟基丁酸戊酸共聚酯(PHBV)作为固体碳源和生物膜载体，去除循环水养殖系统的硝酸盐，并研究固体碳源反硝化反应器不同运行阶段生物膜中微生物群落结构的动态变化。【方法】采用PCR-DGGE技术对反硝化反应器中微生物群落结构的动态变化进行了分析，采用传统纯培养方法分离反应器中降解PHBV的细菌。【结果】连接固相反硝化反应器能使循环水养殖系统中积累的硝酸盐显著降低，并维持在较低水平(小于10 mg/L)，而常规循环水养殖系统中硝酸盐浓度持续增加。系统发育树聚类分析结果表明，反硝化反应器生物膜细菌归属于变形菌门(β-proteobacteria、γ-proteobacteria和δ-proteobacteria)、厚壁菌门(Firmicutes)和拟杆菌门(Bacteroidetes)。反应器运行初期(40 d)的优势种群主要为Acidovorax和Bacillus;运行后期(150 d)的优势种群依次为Clostridium、Desulfitobacterium、Dechloromonas、Pseudoxanthomonas和Flavobacterium。从反应器中分离到的PHBV降解菌株分别归属于Acidovorax、Methylibium、Pseudoxanthomonas和Dechloromonas。【结论】利用PHBV为碳源能有效去除循环水养殖系统的硝酸盐。明确了反硝化反应器在运行过程中，碳源表面生物膜的优势菌群及其动态变化。

Abstract:

Abstract:［Objective］ Polyhydroxybutyrate-co-hydroxyvalerate (PHBV) was used as solid carbon source and biofilm carrier to remove nitrate from recirculating aquaculture system (RAS)．Dynamics of microbial community structure in biofilm coating on carbon source packed into denitrification reactor were investigated．［Methods］ Polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) was used to analyze the microbial community in biofilm from denitrifiation reactor．Bacteria degrading PHBV were isolated from the reactor using pure culture method．［Results］Nitrate decreased remarkably in the RAS connected with dentrification reactor．In contrast，Nitrate increased continuously in the conventional RAS without dentrification reactor．According to the phylogenetic analysis，the microbes in the biofilm samples from denitrification reactor were divided into Proteobacteria (β-proteobacteria，γ-proteobacteria and δ-proteobacteria)，Firmicutes and Bacteroidetes．The major advantageous populations were Acidovorax and Bacillus in the 40-day reactor．The advantageous populations in the 150-day reactor were in order of Clostridium，Desulfitobacterium，Dechloromonas，Pseudoxanthomonas and Flavobacterium．Pure cultures of bacteria degrading PHBV isolated from denitrification reactor were classified into Acidovorax，Methylibium，Pseudoxanthomonas and Dechloromonas． ［Conclusion］Nitrate could be removed effectively from RAS using PHBV as carbon source．Advantageous bacteria and their dynamic changes were ascertained in biofilm from denitrification reactor packed with PHBV．