The Tesearch On Production Of Biofuel From Butyrivibrio Fibrisolvens

Recently.great attention has been paid to the renewable energy with the decrease of fossil fuel and the pollution from the combustion of fossil fuel.Comparing with the first generation bio-fuels,the second-generation bio-fuels is competitive and potential because it produce bio-fuels from lignin-cellulose other than grain.Butyrivibrio fibrisolvens WH-2can ferment cellulose to butyric acid by consolidated bio-processing.Then the butyric acid is converted to bio-fuels,butanol.The strain was mutated and the fermentation medium was optimized to improve the yield of butyric acid. A positive strain was obtained by microwave mutagenesis.It produced0.29g/L butyric acid,which is a increase of33.03%.The mutated strain was stable in production of butyric acid.Medium was optimized by response surface methodology.Firstly,three kinds of medium components with the largest influence on butyric acid concentration was selected by Plackett-Burman experiment. They are NaHCO3.NaCl and MgSO4·7H2O.Secondly,the response region by the steepest ascent path was approached.The center point of the response surface determine as NaHCO37.4g/L, NaCl0.7g/L,MgSO4-7H2O0.24g/L. Finally,the optimal concentrations of the key factors by Box2Behnken design and response surface analysis were determined as NaHCO37.26g/L, NaCl0.80g/L, MgSO4-7H2O0.27g/L.The predicted maximum concentration of butyric acid,0.379g/L,was close to the the experimental value,0.379g/L.The yield of butyric acid was increased32.07%with the optimization of medium.After Butyrivibrio fibrisolvens WH-2was mutated and medium was optimized, butyric acid concentration was increased75.69%.In the research,butyrivibrio fibrisolvens WH-2was found with a capacity of using glycerol as substrate to produce ethanol.To explore the potential of butyrivibrio fibrisolvens in producing ethanol from waste glycerol of the biodiesel industry.Single factor experiment was applied to consider the effect of glycerol concentration, initial medium pH,incubation time, and the addition of CaCO3on the concentration of ethanol. Experimental results showed that low concentration of glycerol was more conducive to the production of ethanol.The alkali environment was helpful to the consumption of glycerol and ethanol production.When the concentration of glycerol was10g/L,initial pH7.5.incubation time was60h, and CaCO3concentration was15g/L,the concentration of ethanol was2.422g/L.and glycerol conversion rate was71.32%.As a result.it is feasible to produce ethanol from the waste glycerol in bio-diesel industry by butyrivibrio fibrisolvens WH-2.