Study On Co-fermentation Of Organic Components Of Kitchen Waste To Produce Hydrogen And Butanol

The treatment and resource utilization of kitchen waste is related to the urban sustainable development and ecological environment protection in China.Using kitchen waste as raw material to produce excellent bio liquid fuel,bio butanol,has attracted extensive attention of researchers at home and abroad.However,the large use of enzyme preparations,low butanol production from fermentation strains,and inhibition of fermentation process products severely limit the promotion and application of traditional biological butanol production technologies.How to improve the treatment efficiency and butanol production of anaerobic fermentation system has become one of the key problems that need to be solved urgently in the field of kitchen waste fermentation to produce biological butanol.In order to improve the efficiency of bio butanol fermentation and hydrogen production from kitchen waste,this study carried out a study on co production of hydrogen and butanol from organic components of kitchen waste by mixed bacteria fermentation.In this study,the metabolic regulation of butanol producing strains fermenting kitchen waste,the isolation and screening of kitchen waste oil degrading strains and the optimization of fermentation conditions,as well as the construction and efficiency evaluation of a two bacteria fermentation system were studied.The research results can provide theoretical basis and technical support for the production technology of bio butanol from kitchen waste.The main research content and conclusions of this paper are as follows:(1)The feasibility of kitchen waste co production of hydrogen and butanol by Clostridium acetobutylicum M6 was studied,the concentration threshold of kitchen waste during butanol fermentation was determined,and the effects of different amino acid combinations and addition time on hydrogen and butanol production by Clostridium acetobutylicum M6 were explored.The results showed that Clostridium acetobutylicum M6 hydrolyzed and fermented 200 g/L kitchen waste,and the yields of butanol,total solvent and hydrogen were 12.83 g/L,22.04 g/L and 14.20 mmol,respectively.Compared with existing butanol producing strains,Clostridium acetobutylicum M6 exhibits higher organic acid reduction ability,solvent production performance,and hydrogen production ability.Adding amino acids can significantly regulate the production of hydrogen and butanol.At 12 hours of fermentation,the addition of amino acids has the most significant promoting effect on the synthesis of hydrogen and butanol.The maximum synthesis of hydrogen and butanol in the valine and arginine groups reached 17.00 mmol and 15.92 g/L,respectively,an increase of 20% and 24% compared to the control group.The maximum synthesis of hydrogen and butanol in the tryptophan and phenylalanine groups was 18.24 mmol and 16.53 g/L,respectively,an increase of 23% and 28%.(2)In order to reduce the inhibitory effect of kitchen waste oil on Clostridium acetobutyricum M6,this study obtained an oil degrading acid producing bacterium H1 through enrichment,domestication,isolation,and screening,and identified it as Clostridium sp.H1 through 16S r DNA sequence.Its main metabolites are acetic acid and butyric acid.The optimization of single factor degradation conditions of Clostridium sp.H1 was studied.The optimal culture temperature was 37 ℃,the optimal inoculation amount was 10%(v/v),the optimal p H was 6,and the optimal concentration of yeast extract was 3 g/L.Under the optimal fermentation conditions,Clostridium sp.H1 can rapidly degrade 82% of kitchen waste oil within 96 hours,while the concentrations of acetic acid and butyric acid reach a maximum of2.86 g/L.(3)The double bacteria fermentation system of kitchen waste was constructed by Clostridium acetobutylicum M6,a butanol producing bacterium,and Clostridium sp.H1,an oil degrading acid producing bacterium.The study found that the optimal culture conditions for the system were Clostridium sp.H1 fermentation for 24 hours,followed by Clostridium acetobutylicum M6 inoculation,with an inoculation ratio of 1:1,culture temperature of 37 ℃,p H of 6,and final butanol and hydrogen production of 16.33 g/L and 18.67 mmol,respectively.Due to the complementary and coordinated metabolism of Clostridium acetobutylicum M6 and Clostridium sp.H1 in oil degradation and butanol fermentation,the co production capacity of hydrogen and butanol from kitchen waste by two bacteria fermentation has been significantly improved.Compared with pure culture,the production of ethanol,acetone and butanol has increased by 1.93,1.19 and 1.34 times respectively,and the hydrogen production has increased by 1.16 times.