Studies Of Coupling System Between Separation And Acetone-Butanol Fermentation To Acquire High Yield Of Butanol

These days, it has been found that butanol is a potential biological fuel which has better performance than ethanol and can be mixed with gasoline in any proportion, so butanol possesses good applied perspective. The method of biological fermentation can be used for production of butanol, but due to the toxicity of high concentration of butanol to microorganisms, yield and productivity by biological production are low, and cost is high. The key of resolving method is increase of conversion rate from raw material to butanol, yield and productivity of butanol. The adoptive techniques conclude molecular mechanism alteration to make the bacterium endure toxicity of butanol, or to heighten the productivity and reduce costs, coupling system of in situ butanol separation at the fermentative process is constructed for fermentation and products extraction.By the cold experiment, toxic trial and fermentation in serum bottle, main technics parameters for coupling system between fermentation and extraction are established. Corn mash is fermented at the temperature of 37℃without agitation till 72 h, and at the time of 24 h oleyl-20% decanol alcohol is added as the organic phase according to the phase rate between phase and aqueous phase of 1:5. Fermentation in fermentor integrates extractive fermentation technic and gas stripping technic, and ascertain persistent flow rate of 0.3 L/min N2 to the corn mash from 24 h to 72 h to carry on gas stripping-extraction-fermentation. The gas stripping-extraction-fermentation technic get 16.39 g/L of final butanol yield and 24.40 g/L of solvents yield, heightening 51.48% and 35.71% separately than the classical ABE fermentation; butanol percentage in the total solvents and conversion rate of raw separately are promoted to 67.17% and 91.93% from 60.18% and 75.91%, and the extraction rate for butanol also achieves to the higher level of 62.34%.To analyze the conversion from raw to products, measuring methods are set up. Overall sugar content measured can be used to ascertain conversion rate, glucose content measured by method of HPLC and biosensor will help to comprehend metabolism of glucose in the dynamic course of fermentation, and HPLC and GC methods which are not reported in the past would help measure product concentrations in the aqueous and organic phase exactly, swiftly and conveniently.Gas stripping-extraction-fermentation technique reduces feedback toxicity resulting from product of butanol to bacterium, and to a certain extent resolves the problem of low yield and productivity, low conversion rate, and the technique shows applicative potential industrialized system to produce butanol.