Carbon Monoxide Fermentation To Produce Fuel Ethanol By C.carboxidivorans

Fuel ethanol is ethanol with a content of 99.5%or more.It can be mixed with gasoline in a certain proportion to provide as fuel.At present,domestic promotion of E10 is a mixture of 10%fuel ethanol and 90%gasoline.Brazil's compounding ratio reaches 27%.Ethanol gasoline prices are only 60%of petroleum gasoline,90%of cities in US use E10 gasoline,E15 gasoline is used in some regions,and China is actively promoting the use of ethanol gasoline.Fuel ethanol has important economic and social benefits for the development of country.Traditional energy alternatives and environmental friendly features have promoted the development of the industry.Fuel ethanol has undergone the transition from sugarcane and corn grain fermentation to cassava and sorghum fermentation to the present.The development of ethanol production from cellulosic ethanol and syngas has encountered a bottleneck in the development of cellulosic ethanol,and the fermentation of syngas also has difficulties to overcome.Therefore,this study selected a excellent production of Clostridium carboxidivorans P7 strain for syngas production of fuel ethanol research.In this study,the strains were thoroughly investigated,including the effects of growth pH,utilization efficiency of syngas,inoculum volume,inorganic salts,trace elements Fe,Zn,Na2S single factor on fermentation.The results showed that the optimum grow pH of the strain was 6.0-7.0,and the utilization efficiency of syngas was very fast.The rate of alcohol production in the early period of the strain was very fast.After the accumulation of acid substances,the metabolic rate of alcohol accumulation decreased.It is equivalent to only one-ninth of the previous rate.The ethanol increase rate in the first 6 days is 445.8 mg/L d,the ethanol increase rate in 6-20 days is 53.7 mg/L d,and the best inoculation amount is 10%.In addition,the amount of inorganic salts,Fe2+,Zn2+,and Na2S will affect the concentration of fermentation products,regulate metabolic pathways,and increase the metabolism of alcohol-producing pathways through regulation.Fe2+ concentration 4X,Zn2+ concentration X,and Na2S addition amount 3X produce higher concentrations of alcohol.Finally,the study of immobilization of the strains was carried out.The results showed that the liquid activated charcoal can increase the ethanol concentration by 33%and the total product concentration by 36.8%.