Study On Domestication And Pretreatment Technology Of Anaerobic Fermentation Inoculants Of Vegetable Waste

Based on the anaerobic fermentation of cattle manure,an inoculum suitable for anaerobic fermentation of vegetable waste is domesticated by adding a certain amount of vegetable waste.The 16 S r DNA sequencing technology was used to analyze the microbial diversity of anaerobic fermentation inoculum of vegetable waste before and after domestication.In order to improve the methane yield of anaerobic fermentation of vegetable waste,response surface methodology was used to analyze the effects of crushing size,feed liquid concentration,pretreatment time and calcium oxide addition on the anaerobic fermentation of vegetable waste.And carry out saliency and interaction analysis.The 16 S r DNA sequencing technology was used to analyze the microbial diversity in the anaerobic fermentation feed of vegetable waste before and after pretreatment.The results obtained in this paper are as follows:1.At 35 ?,14.6 g VS vegetable waste liquid was exchanged every day for 20 days to obtain an inoculum with a p H of 7.46.It was found that that amount of inoculation was 1.1g VS/800 ml,and the domestication group had an increase of 119%.In addition,the biogas production in the taming group was stable.The microbial diversity of domesticated and unaccomplished groups was analyzed by high-throughput sequencing.The results showed that at the genus level,the dominant bacteria in the domesticated group were Cloacibacillus and Aminivibrio,with abundance of 22.1% and 22.04%,respectively.And the benefits of both bacterial strains to produce organic acids,beneficial to produce methane.The dominant bacteria in the unaccompanied group are mostly promoting cellulose degrading bacteria.The dominant archaea in the domesticated group were Methanospirillum and Methanothrix,and their relative abundances were 51.47% and 46.77%,respectively.The domesticated group did not produce new strains compared with the unaccomplished group,but the relative abundances of the two dominant archaea were higher than those of the unaccomplished group.After acclimation,archaea is mainly hydrotrophic and mainly degrades acetic acid,which could stabilize anaerobic digestion process.2.At 35?,the results show that the order of influence of each impact factor on methane yield is: Acidizing time>crushing size>feeding liquid concentration>calcium oxide addition amount.The optimal treatment conditions for hydrolytic acidification are: The crushing size was (5±1)cm,the concentration of the feed liquid was 1.52%,the acidification time was(103±1)h,and the amount of calcium oxide added was 4 g·L-1.The cumulative methane yield can be increased by more than 43.85% in the control group.3.The Illumina Mi Seq high-throughput sequencing technology was used to study the microbial diversity of pretreated and unpretreated anaerobic fermentation feeds of vegetable waste.25 bacteria and 13 archaea were detected from the treatment group,and 20 bacteria and14 archaea were detected in the control group.Pretreatment enriched the diversity of the flora in the feed solution.The optimum crushing particle size,feed liquid concentration and pretreatment time can increase the accumulation of organic acids,which is beneficial to the production of acid-producing bacteria.The addition of calcium oxide can make the whole fermentation system in a weak base environment,and increase the number of acid-producing bacteria suitable for neutral or weak base environment,such as Sporosarcina.And the pretreated liquid bacteria are mainly composed of acetic acid and hydrogen nutrient methanogens.