Study On Production Of Biomass Energy From Sweet Sorghum Fermentation Residue

The ethanol production use the sugars in sweet sorghum by solid fermentation technology has been industrialization.The main components of fermented residues are cellulose,hemicellulose and lignin.The total use of the residues can reduce the pollution on environment,increase the economic benefit and promote the positive social benefit.This paper studied the synthetic use of sweet sorghum residues by solid fermentation.First of all,the hemicellulose in residues was used to produce bio-chemical products,which adopted two-step method.In the condition of microwave irradiation,dilute sulfur acid catalyzed the degradation of xylose. The influence of reaction temperature,sulfur acid concentration and the ratio of solid to liquid on xylose yield and concentration were determined by respond Surface Method.The optimized raction conditions :the reaction temperature was 120℃,the ratio of liquid to solid was 5,the sulfur acid concentration was 1.2% and the reaction time was 85 min.The obtained optimum xylose yield and xylose concentration by RSM were 46.6% and 15.1g/L respectively.The experimental results indicated that they were 45.3% and 14.5g/L respectively.The compare of model prediction with experimental result indicated that the difference was not significant.Besides,the kinetic study on xylose degradation to furfural using dilute sulfur acid as a catalyst under microwave was maded.The influence of acid concentration,reaction temperature and reaction time on furfural yield was researched.Then,the rate constant, reaction active energy and pre-factor were calculated.In the end, the kinetic model on xylose degradation was built.The results indicated that the active energy of xylose degradation was 48.05kJ·mol-1 and the maximum furfural yield reached 53.5%.By follows,use of cellulase on the fermentation residue after acid hydrolysis conditions were optimized.The reacted residues were proposed by filtration,In addition, the filtrated residues contained cellulose,lignin and little hemcellulose.The components of residues were changed after disposed by sulfur acid and microwave irradiation.The crystal structure of cellulose was destroyed,which benefited the enzyme hydrolysis and fermentation.Use cellulase hydrolyzed the residues,enzyme hydrolysis efficiencies of mass concentration,enzyme usage,rotation rate of shake bed and surface active reagent were researched.The obtained optimum enzyme hydrolysis conditions as follows: mass concentration was 130g/L, enzyme usage 11FPU/, tween-80 usage was 1% and rotation rate was 140r/min.The results indicated that the cellulose yield reached 62.3% after hydrolyzing 48h,and the reductive sugar concentration reached 53.2g/L.Finally,the ethanol fermentation conditions were optimized.Adopting synthesis saccharification and fermentation technology,the Anqi high active dry yeast was used produce ethanol as bacterium.The influence of temperature was studied,and 38℃was selected as a fermentation temperature.Besides,the influence of different N sources was studied.By adding organic N resource in fermentation process was better than inorganic N resource.The yeast cream was better than peptone.The optimum yeast cream addition was 1%,ethanol concentration was 22.76g/L.By compared of simultaneous saccharification and fermentation(SSF) and separate hydrolysis and fermentatiaon(SHF),the results indicated that the cycle of SSF was shorter than SHF and the ethanol yield was higher than SHF.