Study On Ethanol Fermentation Of Jerusalem Atichoke With KOJI

Fuel ethanol, which is renewable, full burning and less pollution, is used widely in the world as a new kind of alternative energy. At present, grain starches, such as wheat and com starch, are used in fuel ethanol production. However, with the rapid growth of economy and population, these methods are directly threats to food security in China. Jerusalem artichoke, which is a kind of alternative raw materials for ethanol, is used as a new type of energy crop. Jerusalem artichoke is a non-grain crop, has high production, broad planting area and high energy. It can be hydrolyzed and fermented to ethanol, which is very valuable to be studied. Compared with starch, the temperature for paste of Jerusalem artichoke is lower, which has advantage in energy conservation.The traditional method of koji-making was a process of different strains of microorganisms competing for materials, the microorganisms, which adapt to the environment of koji, will grow and reproduce. In this process, they accumulated a wealth of metabolic products and a wide variety of enzymes. In addition, compared with the fermentation of a single strain, the traditional fermentation of koji can provide a richer and industrial ethanol. Whereas, koji had more abundant strains and more stable enzymes, and gelatinization temperature of Jerusalem artichoke was lower than the starch. In this study, Jerusalem artichoke was used as a raw material for fermentation and koji was used as fermenting power. The traditional process of glucose transformation into ethanol is uncomplicated, however, hydrolysis product of Jerusalem artichoke powder, including glucose, fructose, oligosaccharides and so on. The high concentration of single sugar could inhibite the synthesis of jerusalem artichoke powder. To solve the problem metioned above, we selected a suitable koji for the fermentation of Jerusalem artichoke in a large number of koji resources and optimizated the parameters of fermentation conditions. The results are as follows:1. Anqi liquor-making koji, Anqi Liqueur Koji and Xinma Liquor Industry Koji were used to study in one-step fermentation experiment. Compared to the other two kinds of Koji, Anqi liquor-making koji was more suitable for the production of ethanol and fermentation of Jerusalem artichoke.2. The sugar content of Jerusalem artichoke as a raw material had a direct impact on fermentation. Therefore, we should choose no decay and fully mature Jerusalem artichoke tubers as raw materials for fermentation. Combine the experimental results with the reality of the situation,40mesh as the grinding degree was the most appropriate degree for fermentation. Sterilized fermentation of Jerusalem artichoke syrup was better than the situation which is not sterilized. Therefore, the Jerusalem artichoke syrup should be sterilized before adding koji into it.3. According to the single factor experiment, the key factors of the fermentation consists of solid-liquid ratio, the percentages of koji, fermentation temperature and time. The result of orthogonal test are as follows:The initial pH5.5, solid-liquid ratio1:4, the percentages of koji was0.3%of the Jerusalem artichoke powder, fermentation temperature32℃and fermentation time60h. In this condition, the alcohol degree was12.7%vol, ethanol yield was40.1%.