Experimental Study On The Potential Of In-situ Hydrogenation To Enhance The Methane Production Of Anaerobic Fermentatio

As an important energy gas,methane plays an important role in reducing agricultural pollution and carbon emissions and achieving the goal of carbon neutrality.In this paper,the effect of Trichoderma pretreatment and in-situ hydrogenation on methane production from anaerobic digestion（AD）of corn stalk were studied.The following research results and conclusions have been obtained:（1）Explored the effect of Trichoderma pretreatment on methane production of corn straw in AD.The results showed that the optimal pre-treatment conditions for Trichoderma was:pretreatment temperature of 36℃,initial solid-liquid ratio of 1:1,and pretreatment time of 2 days.Under this pretreatment condition,the yield of reducing sugar was 27.66 mg·g^-1,the maximum daily methane production was 34.58m L·g^-1TS,and the cumulative methane production was 112.20 m L·g^-1TS,which was1.36 times higher than the untreated group.These results indicated that the potential of methanogenesis in AD of corn stalk was effectively improved by Trichoderma pretreatment.（2）The effects of hydrogenation duration,amount,and frequency on gas production performance in AD were studied.The results showed that the optimal hydrogenation conditions was:the hydrogenation amount was 60 m L·d^-1,the hydrogenation duration was 13 minutes·times^-1,and the hydrogenation frequency was3 times·d^-1.Under this condition,the maximum daily methane production was 37.05m L·g^-1TS,and the cumulative methane production was 154.76 m L·g^-1TS,which was19.81%higher than that of the non-hydrogenated control group,this results in an increase in methane production and a decrease in the carbon dioxide content in biogas.（3）Microbial community structure and diversity at different stages of AD in in-situ hydrogenation were analyzed.The result showed that the main dominant bacteria groups were Firmicutes,Bacteroidetes,and Euryarchaeota after hydrogen was introduced.And Methanothrix,Methanocullus,Methanosarcina,and Methanobrevibacter were the main methanogenic archaea.Due to the introduction of exogenous hydrogen,the growth and reproduction of methanogenic archaea such as Methanosarcina and Methanobacterium were promoted,and the methanogenic metabolic pathway of hydrogen-eating methanogens using H₂and CO₂as substrates was promoted,thus increasing the methane yield.