Study On Lignocellulose Saccharification Mode To Hydrolysis Yield And Scale Up In Commercial Scale Biorefinery Process

Increasing the solids loadings of saccharification is very important to improve a high concentration of monosaccharides hydrolyzed, which can achieve the fermentation broth contained high concentration products, so as to reduce the biorefinery processing costs. In order to improve saccharification efficiency under high solid content, the efficient stirring paddle is necessary. However, in the industrial production process of ethanol and biological chemicals, the scale of the bioreactor may be in the hundreds or thousands of cubic meters, using impeller is impractical. This paper developed a new kind of saccharification called two-stage enzymatic hydrolysis, which make the efficient mixing to get along with industral production. The results showed that the difference between two-stage enzymatic hydrolysis and normal saccharification are smaller with increased of solid content, when the solid content reach 30%, the difference of yield between two-stage enzymatic hydrolysis and normal saccharification can be ignored. In the two-stage simultaneous saccharification and fermentation(ts-SSF) experiment, enzyme dosage were 5,10 and 15 FPU DM/g, after 72 h, the ethanol yield were 43.32%,58.26% and 61.85% respectively, while the ethanol yield by simultaneous saccharification and fermentation (SSF) experiment were 44.10%,57.67% and 61.04% respectively. Compared with SSF, not only did not reduce the ethanol yield by ts-SSF, but also reduced the stirring power, what’s more, the bubbles broke easily, so two-stage SSF will not form high foam layer what formed in the the entire mixing SSF, the foam flooding was mitigated greatly with the two-stage mixing tactics, these advantage make ts-SSF more appropriated to the industrial scale biorefinery plants.In this thesis, the effect of particle size reduction on overall surface area and enzymatic hydrolysis yield of corn stover was also investigated. It was found that the effective contact area of cellulase and corn stover did not change with the decrease of particle size, which cause the enzymatic hydrolysis rate did not change. This result provided a reference when a proper size reduction of lignocellulose materials is considered in biorefining.