| Reference to the vacuum -pumping line in tianguan enterprise group,we maked a small similar reactor, on which we did some experiments on medium condition suited to the reactor, process parameters during pumping and physiological and biochemical effects of yeasts in negative pressure. according to the rise of acidity,we did some aerobic,anaerobic plate, and DGGE analysis.The main conclusions of this thesis included the following four parts:Firstly, the following was of the conditions of the fermentation medium fit for equipment and process parameters: The proportion of water,corn and cassava is 4:1:1; The concentration of seed liquid is 1g dry yeast/100ml water; The inoculation amount is 10%.This conditions can make sure materials don't block pipes, alcohol degree is high and residual sugar is low.Secondly, the following was of the optimal conditions of pumping alcohol:5kpa of atmospheric pressure, 40℃of pumping temperature,10 alcohol degree of begin pumping period. The orthogonal experiment result of temperature,atmospheric pressure and alcohol proved the process conditions right.Thirdly, By platel and microscopic observation,the effect of negative pressure to yeast'activity and shape was found; Pumping alcohol decreased the Inhibition of alcohol, increased the speed of consuming sugar, The production rate,yield rate and gain rate of pumped sample were 74.72g/L,1.067g/(L.h) and 0.372g/g, While the production rate,yield rate and gain rate of control were 74.4g/L,1.06g/(L.h) and 0.377g/g;the yield of glycerol and by-products related to energy metabolism rised during pumping, some sugar transformed into somatic maintenance energy,which was proved by metabolic flux; On the results of fermentation experiment,yeast fermentation kinetic model was eastablished.Fourthly, mixed bacterium colony were found on plates, The reason why acidity was high may be related to the colony b,the colony c and the colony e.
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