Research On The Ethanol Production Process Of Kitchen Waste With High Solid Content

Compared with the traditional anaerobic fermentation process,the process of dry anaerobic fermentation has the advantages of less biogas slurry,less secondary pollution,raw material resource and high availability of product ethanol.In this paper,the dry fermentation system of kitchen waste inoculated with yeast was studied.The effects of yeast on the ethanol production characteristics of food waste and the effect of amylase on the hydrolysis characteristics of high retention rate food waste were mainly investigated.Finally,through the bio-enhancing technology,the dry fermentation of kitchen waste with high solid content was realized to produce ethanol.（1）The ethanol production characteristics of yeast-enhanced kitchen waste with high solid content were studied.The results showed that yeast inoculation can significantly increase ethanol production.When the yeast inoculum was 9%,after 12h of fermentation,the maximum ethanol concentration was 12.09 g·L^-1,which was8.57 times that of the non-inoculated group.Different from the slowly increasing trend of the concentration of ethanol in the sterilized group,the unsterilized group was mainly concentrated in ethanol production within 0 to 4 h in the early fermentation stage,and the inoculum can reach 88.86%of its maximum value after 4 h.Therefore,it can be fermented for 12 hours according to the application At the end of fermentation,35.11%of the reduced sugars could not be used by yeast,and the highest starch degradation rate was 36.25%.（2）The characteristics of amylase-enhanced hydrolysis of kitchen waste with high solid content to produce reducing sugars were explored.The results showed that the optimal time for amylase promoting starch hydrolysis was 24 h.With the gradual increase of amylase activity,starch degradation efficiency and reducing sugar content gradually increased,and p H gradually decreased.In this study,the best effective amylase enzyme was 180 U·g^-1,the starch degradation rate was 49.68%after 24 h,and the reduced sugar content was 204.25 mg·g^-1.（3）An attempt was made to combine the amylase-enhanced starch hydrolysis process suitable for high-solids kitchen waste and the dry fermentation process of yeast-enhanced kitchen waste to produce ethanol.Ultimately,through biofortification,improved ethanol production from high-solids food waste was achieved.The process can theoretically achieve higher ethanol yield and realize the recycling of high retention rate of kitchen waste.The maximum ethanol production potential obtained by the kinetic fit was 11.51 g·L^-1when the inoculum was 9%in the unsterilized group,and the highest maximum ethanol yield per unit was 3.88 g·L^-1·h^-1,which matched the results obtained in the actual experiments.In terms of the use cost of the bacteria agent,the use of amylase and yeast has achieved good practical utility and economic benefits.