Using Corn Cob Hemicellulosic Hydrolyzate Fermentation Of Candida Shehatae Ethanol Production

Lignocellulose biomass is the most affluence renewable resources all over the world.With the development of the society,human requirement of energy is increasing and making the use of biological technology to ferment ethanol by lignocellulosic biomass,to substitute fossil fuels as energy provider,possess important practical significance and social value.In the craft of lignocellulose biomass ethanol production process,the effective use of hemicellulose hydrolysates is the key factor reduce the cost of ethanol production.The the procedure of lignocellulose hydrolysates to produce fuel ethanol mainly include three steps:pretreatment,saccharification of lignocellulose and sugar fermentation to produce ethanol..As the hydrolysis of hemicellulose fermentation inhibitors produce a large number of fermentation inhibitors which can affect the subsequent fermentation, the hemicellulose hydrolysis need to be detoxification before it used to the fermentation.In this study,orncob was used as raw materials of ethanol fermentation,approached the possible of ethanol production with corncob hemicellulose hydrolysates which was fermented by Candida shehatae,and optimized the craft of pretreatment,the craft of detoxification and the fermentation technology.By the further study of corncob pretreatment and detoxification process, investigated the impact of corncob particle size (10-20 and 20-40 head mesh) on pretreatment and hydrolysis saccharification and ultimately definited pretreatment corncob particle of diameter of 10-20 mesh,soaked in ammonia concentration of 10% for 24h,totally removed the main inhibitor acetic acid by 93.4%,and 32.3% phenolic compounds was removed,which greatly improved the corncob hemicellulose hydrolyzate fermentation performance and reduces the complexity of follow-up detoxification process and drug consumption.The detoxification process simplified:only include vacuum concentration, CaO neutralization and 2% activated carbon GH-13 adsorption. The detoxificat hemicellulose hydrolyzate is extremely suitable for alcohol fermentation.Through hemicellulose hydrolyzate toxic acclimation of the incipient strain Candida shehatae HDYXHT-01,increased its capacity,to ferment corncob hemicellulose hydrolyzate to ethanol. Orthogonal experimentnal was used to definite the best shake flask fermentation conditions of corncob hemicellulose hydrolyzate fermentation:the multiple of the hemicellulose hydrolyzate concentration was three (including glucose, 5.12g/L,xylose 68.7g/L,arabinose,10.19g/L acetic acid 0.51g/L),Medium volume 60mL/250mL flask,fermentation time was 64h,pH 5.4,and inoculum size was 8%.The other fermentation conditions:ammonium sulfate 0.36g/L,potassium dihydrogen phosphate 2.68g/L,yeast extract,2.59g/L,magnesium 0.1g/L,cultured at 30℃,shaking speed 140r/min.The optimal fermentation process of ethanol productivity reached an average of 27.014g/L,which was 1.82 times of initial maximumyield (14.82g/L).Through the ethanol acclimation the incipient strain Candida shehatae HDYXHT-01 alcohol tolerance capacity was increased from 3% to 4%,further enhanced its highalcohol-concentration fermentation potential.It shows that Candida shehatae has some potential to be used to ferment corncob hemicellulose hydrolyzate to produce alcohol and laid a solid foundation.for the further use of this yeast to alcohol fermentation.