Raw Material Gasification Wastewater Biodegradation Of Ethanol And Biomass Dilute Acid Hydrolyzate Fermentation

I here is rarely reported on the biodegradation of biomass gasification wastewater with microorganisms so far in the worldwide, and lacks of the process of treating this kind of wastewater. The treatment efficiency of biomass gasification wastewater can be improved by using combined methods of biology and other physicochemical methods.In the experiment, biodegradability of gasification wastewater and tar was demonstrated by microorganisms at first, the results indicated that microorganisims had the ability to degrade COD in gasification wastewater and tar, but the degradation efficiency was lower with longer (?)action time and lower substrate concentration. In order to increase treatment efficiency, the screening of strain decomposing COD in gasification wastewater was conducted, the results demonstrated that mixted strain gained better COD removal rate than that of single strain. Finally in the lab scale experiment step, two strains of Pseudomonas sp1 and Pseudomonas sp2 preserved in our lab, were used to treat biomass gasification wastewater, the characteristics of degradating COD in the wastewater by the two strains was elucidated, the results demonstrated that mixed culture of the two strains had a high ability to decrease COD concentration in the wastewater, and immobilized cells of the mixed culture were conducted to treat gasification wastewater including the operation of biofilm reactor, entrapped cells reactor, and granular activated carbon adsorption reactor. The results indicated that granular activated carbon adsorption reactor reached to the high removal rate of COD and short hydraulic retention time, as well as the aromatic compounds were degradated efficiently. The paper also reported the excellent nitrogen removal performance from the wastewater using SBR process.Lignocellulosic biomass, a low-cost renewable resource including forestry waste, agricultural residues and municipal solid waste, can be potentially fermented into ethanol by microbial technology that would fulfill increasing demand in fuel. Lignocellulose-derived ethanol is an environmentally friendly liquid fuel, because exhausted carbon dioxide is taken up through growing biomass and therefore makes no net contribution to the atmosphere. However, from the hydrolysis of lignocellulosic materials to detoxification of hydrolysates, from strains' selection and adaptation to fermentation, there are countless problems that need to be solved and numberless works that need to be done. The aim of this research is to get an effective, simple and low-cost method, and promote the lignocellulose-derived ethanol to be produced on a large scale.In my research, first, the strain selection of both ethanol and inhibitor tolerance were conducted from 21 strains including yeasts and bacterium by the experiments of xylose fermentation, hydrolysates selection and ethanol fermentation. As a result, Saccaromyces cerevisiae, Pachysolen tannophilis and recombinant Escherichia coli was selected for next experiments. Two groups of co-cultures were utilized in the adaptation experiment. One was S. cerevisiae mixed with P. tannophilis, and the other was 5. cerevisiae mixed with recombinant E. coli. After adaptation, two groups of co-cultures were used in the fermentation experiments, including batch fermentation, fed-batch fermentation and intermittent fed-batch fermentation, and some better results were achieved. I also make the fed-batch fermentation with fermentor, from which I examine the feasibility of using fed-batch fermentation on a large scale. In addition, I also study the fed-batch ethanol fermentation of two yeast strains.of toxic-tolerance.According to these experiments, I get an integrated method about ethanol production from lignocellulosic materials and achieve expected results.