Study On The Potato Ethanol Fermentation

Ethanol were extensively applied in the foodstuff,chemical industry,medicine，dyestuff，national defense,et al. field. It was also one of regeneration energy source to become partsuccedaneum of petroleum. For this reason,the research on ethanol fermentation attractedmore attention. The ethanol production with potato is a new alternative according to thecurrently national industrial policy that using non-food crops for ethanol production,furthermore, potato were also extensively grown in our country. On the basis of metabolismpathway of yeast,the ethanol fermentation using potato as material was done as follows:Fresh potato was used as raw materials for the ethanol production.The simple factorexperimental result indicated that the optimum conditions was as follows: raw materialsfiltered by40screen mesh; with the ratio of raw materials and water as1:0.3; liquefyingconditions:10U/g high temperature resistant α-amylase,pH value as5.5～6.0,60minliquefaction at90℃～95℃;the asynchronism saccharifiction fermentation,200U/gglucoamylase,60min saccharifiction at60℃;fermentation initial pH as3.5;fermentationtemperature at32℃;more seed volume preferred.The orthogonal experimental resultsindicated the optimum conditions of fresh potato fermentation were as follows:fermentationinitial pH of3.5,yeast inoculation volume of0.1%ADY（w/w）,the former10hoursfermentation temperature30℃and later stage32℃.In this condition ethanol Content reached8.8%（v/v）.The inorganic ion addition of Ca²⁺,Mg²⁺,Zn²⁺,NH⁴⁺could elevate ethanol contentof ripe fermented mash.The research on ethanol high gravity fermentation with potato dry powder （filtered by40screen mesh） was carried out: the ratio of material to water as1:2.0;liquefying conditions:10U/g high temperature resistant α-amylase,pH5.5～6.0,90℃～95℃;with the method ofsimultaneous sacchrifiction fermentation（SSF）,200U/g glucoamylase and fermentation initialpH3.5;fermentation temperature at35℃.Cellulose （pH5.0,30min incubation at50℃）,pectinase（pH5.0,60min incubation at45℃） and acid proteinase could efficiently elevate theutilization ratio of starch,but pullulanase did not have the good effect as theseenzymes.Tween-80could also increase the ethanol tolerance of yeast cell. The orthogonal experimental results indicated the optimize fermentation conditions were as follows: with10U/g cellulose and20U/g pectinase before liquation, with20U/g acid proteinase and0.03%tween-80.In this condition the ethanol content can be up to16.4%（v/v）,and the utilizationratio of the starch was94.18%.By comparison on fermentation capacity to strains used in potato ethanol fermentation,S.cerevisiae FCC2109made the best result in fresh potato ethanol fermentation.Ethanolcontent was9.1%（v/v）, and the utilization ratio of the starch was98.67%.Fermentation timewas25h. In potato ethanol HGF, S.cerevisiae FCC2123was selected. Ethanol content was16.0%（v/v）, and the utilization ratio of the starch was95.06%. Fermentation time wasmerely47h.Above-mentioned experiment could be proved, it is feasible that potato is used forethanol fermentation for above95%of the utilization ratio of starch and extensivesource.Consequently, potato has brilliant outlook as raw material to produce ethanol.