Preliminary Study Of Ethanol Fermentation Process From Jerusalem Artichoke

As the rapid growth of economy, the problem of resources deficiency attracts more people’s attention. Various countries are striving to develop new type of resources, a substitute of fossil fuel. Meanwhile, many countries have come to an agreement on the address of resources crisis. The utilization of non-grain biomass producing ethanol can assure food security, as well as fundamentally address the resources crisis. Energy Jerusalem artichoke features higher productivity, greater cold-resistant ability and tolerant capacity to drought. It also has stronger resistance of sand drift and reproductive ability. Thus making the plant enjoys big competitive advantages.This paper focuses on studying the processes of ethanol production from energy Jerusalem artichoke. The main processes include inulin gelatinization, acidolysis and yeast fermentation. Studies were carried out on (1) the study of inulin gelatinization, including the time for inulin gelatinization, the impact of different reduction ratio on inulin gelatinization;(2) the study of process conditions for acidolysis, priority was given to study the effects of temperature, reduction ratio, ratio of material to water and the volume of sulphuric acid, the optimal time for acidolysis was achieved, providing parameters for the next ethanol fermentation;(3) the study of ethanol fermentation from energy Jerusalem artichoke, mainly concentrating on the influence of inoculum concentration of yeast, ratio of material to water, initial pH value, temperature on ethanol fermentation, fermentation time was defined and the difference between sterilization and without sterilization for ethanol production was studied.Firstly, it is necessary to determine the time for inulin gelatinization and gelatinization temperature for inulin with various reduction ratios. The gelatinization temperature for inulin ranges from40-55℃, which is lower than that of starch bearing material. The gelatinization times of30minutes within the temperatures are favorable for the next acidolysis. The thinner the reduction ratio, the shorter the gelatinization time will be taken, so does the lower gelatinization temperature. The elevation of reduction ratios can increase the production cost for fermentation. Therefore, the appropriate reduction ratio for inulin is40items.Secondly, the acidolysis conditions for the process through single factor experiments include:the temperature for acidolysis is50℃, the volume of concentrated sulphuric acid is2.5%(v/v), and the time for acidolysis is60min. The DE value of the solution reached66.66%, and the conversion rate for inulin is94.86%.Thirdly, experiments of the influence of sterilization or without sterilization for ethanol production were carried out. Results show that sterilization can enhance the ethanol production. The best parameters for the process through single factor experiments were:8%(m/m) of the inoculum concentration of yeast, ratio of material to water is1:8, initial pH value is5.0, the fermentation temperature is36℃, and the time for fermentation temperature is36h. Under this condition, ethanol concentration reached11.5%and above in the mixed liquor, and2g/L of the residul sugar.Through the above experiments, we concluded the best process conditions for ethanol production, with the purpose of enhancing the ethanol productivity by the greatest extent, and providing theories for industrialized production.