Study On New Technological Process Of Wheat Ethanol Fermentation

Ethanol is the product of fermentation industry which has now the most long history and biggest yield in the world. It is extensively applied in the food, chemical industry, medicine, dyestuff, national defense etc, and it is also a very important cleaning energy. However, the tradition fermentation technology has made a serious effect on environment. A mount of waste water to discard has polluted the river, especially the residual water to discard after distillation. A new technological process which is put forward from the aspect of high concentration ethanol fermentation, cleaning production and synthetical- utilization of wheat has been studied on ethanol fermentation in clarifying solution systematically and intensively in this paper. TH-AADY and two- enzymes of low-temperature cooking and liquefaction correlate process is adopted in this new technological process.In this paper, new technological process of wheat fermentation in clarifying solution from wheat flour is intensively and systematically studied. With this process, the gluten is separated from the solution before fermentation. The gluten contains good nutrient and can be processed into delicious health food and this process has high efficiency of synthetical utilization of wheat. On the other hand, with this process the fermentation liquor has good liquidity.The high gravity fermentation is to increase the ethanol content of the fermentation liquor in order to decrease pollution and lower the cost. From the ethanol production process, high gravity fermentation have advantages of decreasing the quantity of waste water and load of managing it, saving product water, lowering equipment investment, enhancing the efficiency of usage of the fermentation equipment, decreasing the cost steam in distillation and liquefaction process etc. In consideration of the high sugar causing high permeating press and low water activity, repressing the growth and fermentation of yeast, wheat feed-batch fermentation in clarifying solution is intensely studied to relieve the growth of yeast and fermentation repress. At the same time, it is to break the normal using thick fermentation liquor, to abandon high viscidity and difficulty of transporting heat and mass etc.The level of extracting active gluten has been investigated by regiment method (the system of Martin) in this paper. The experiment data indicate that ratio of extracting gluten of different 1:4.0,1:3.5,1:3.0 material and water ratio is generally 12—13% or so.The effect of 1:4.0,l :3.5,1:3.0 material and water ratio on fermentation in clarifying solution by means of shaking flask experiment is studied in this paper. 1:4.0 material and water ratio is suitable and benefiting to be the initial material and water ratio of feed-batch fermentation with quick fermentation speed, fermentation cycle 60h and low residual reducing sugar; The producing ethanol rate of wheat flour is 39.56%; the starch utilization is 93.5%; the ethanol concentration can reach above 11% respectively. Although 1:3.5,1:3.0 material and water ratio can get the higher ethanol concentration, residual sugar is high and starch utilization is low and wasting food.In fermentation in clarifying solution, initial feed-batch time and last feed-batch time is studied through the growth curve of yeast and the rates of sugar intaking.In this paper, the orthogonal experiment design is used to optimize the process conditions of ethanol feed-batch fermentation process in clarifying solution. The results of orthogonal experiment indicate that with the purpose of enhancing the starch utilization, the optimal technology is as follows: feed-batch way is progressive increase; the initial feed-batch time is 10h; the feed-batch interval time is 8h; the fermentation cycle is 72h. The results of orthogonal experiment also indicate that with the purpose of getting high output of ethanol, the optimal technology is that the feed-batch interval time is 8h instead of 4h with other conditions invariability except the above combination. Under this conditions, the starch utilization can get 91.96% and the output of ethanol reaches 0.1046g/ml. Because the influence of feed-batch way is low, the optimal combination is A2B2C2D3 in order to operate simply and implement industrialization. The optimal combination gets satisfactory results in 5L auto-fermentor of small-scale test.