复合碳源培养对酒糟厌氧消化液中丙酸互营氧化菌及群落结构的影响

Effects of Composite Carbon Source Cultivation on Propionate Syntrophic Oxidizing Microbes in Anaerobic Digestive Juice of Stillage and Microbial Community Structure

丙酸累积是影响厌氧消化系统稳定性的主要因素,为了考察酒糟厌氧消化过程中间代谢产物的累积情况,以总固体含量(TS)(质量分数)5%和7%的白酒糟为发酵原料进行了批次试验。结果表明,乙酸(最高浓度33~129 mmol/L)、丙酸(39~61 mmol/L)、丁酸(5~44 mmol/L)和15种氨基酸(0.01~0.3 mmol/L)为主要中间代谢产物。为了探究其中关键的丙酸降解菌群,以酒糟原始沼液JO为植种源,10 mmol/L丙酸和0.1 mmol/L混合氨基酸为复合碳源进行富集培养,获得中温厌氧丙酸-氨基酸培养系JO-AP。高通量测序分析表明,互营丙酸降解菌与厚壁菌门(Firmicutes)的丙酸厌氧降解菌(Pelotomaculum schinkii)近缘,16S rRNA基因相似性100%,占细菌总丰度的16.7%。对比酒糟原始沼液JO、丙酸培养系JO-P及丙酸-氨基酸培养系JO-AP中的主要功能菌群,发现采用单一碳源和复合碳源获得的优势互营丙酸降解菌不同;传统培养与分子生物学技术相结合可以更全面地掌握系统中的微生物群落组成。

Propionate accumulation is a main factor affecting the stability of anaerobic digestion system.In order to study the accumulation of intermediate metabolites during anaerobic digestion,spirit stillage with total solids(TS)content of 5%and 7%were taken as raw materials in batch experiments.The results showed that acetate(maximum concentration 33-129 mmol/L),propionate(39-61 mmol/L),butyrate(5-44 mmol/L),as well as 15 amino acids(0.01-0.3 mmol/L)were the main intermediate metabolites during anaerobic digestion.In order to study key propionate degradable bacteria community in it,distillage juice was taken as planting source,10 mmol/L propionate and 0.1 mmol/L mixed amino acids as composite carbon sources to carry out enrichment cultivation,and obtained medium temperature anaerobic propionate-amino acid culture system JO-AP.High throughput sequencing analysis showed that syntropic propionate degradable bacteria were close sib to Pelotomaculum schinkii with 100%similarity of 16 S rRNA gene,and accounted for 16.7%of total bacterial abundance.Comparing the main functional bacterial communities in propionate-amino acid with initial stillage juice,propionate,and propionate-amino acid cultivation system,it was found that the dominant syntropic propionate degradable bacteria differed from adopting single carbon source from composite carbon source;combination of traditional cultivation with molecular biology technology can master more comprehensively the microbial community in the system.