Bioethanol Production And Comprehensive Utilization Of Corn Stover

Energy bears a massive influence on the maintenance and progress of the human society. Fossil energy, among various forms of energies, is the paramount ever since the appearance of the modern civilization on this planet, through which the modern industrial civilization is founded. However, the world confronts the depletion of the fossil energy and environmental crisis due to its increasingly expanded consumption. Therefore the development of renewable energy is urgent, among which biofuels, in particular bioethanol, are touted as a key partial solution both to the world's mushrooming energy demands and environmental burden. It is thought to be attractive to produce bioethanol from the lignocellulose which is the most abundant and reproducible material on earth.Four steps are employed in converting the lignocellulose to bioethanol: pretreatment, hydrolysis, fermentation and separation. The processes including pretreatment, xylose exploitation and cellulose decomposition are tough through the way of producing bioethanol.Dilute sulphuric acid pretreatment was adopted as the main pretreatment method, which showed 130℃, solid load 5 %, acid concentration 0.75 % (v·v^-1) and pretreatment time 30 min were the optimal level by single factor experiment. Dilute phosphoric acid pretreatment should proceed under 125℃, 1.00 % (v·v^-1), 1:30 and 50 min suggested by the experiment.Xylose yielded in the dilute acid pretreatment was used to cultivate genetic recombinant Escherichia coli BL21, with Human-like Collagen (HLC) expression enhanced by 50.00 % and 63.71 % xylose consumption, and cultivate the biohydrogen production bacterium Enterobacter FML-C₁ with the maximum biohydrogen production at 460 mL of hydrogen per liter of medium, and 80.93 % xylose consumption.The work of cellulose decomposition focused on the screening of the efficient cellulose degradable strains. Primary screening (by filter-paper Hutchison solid culture medium and sodium carboxymethylcellulose solid culture medium) and reelection (by filter-paper inorganic salt culture medium and sodium carboxymethylcellulose Congo red culture medium) indicated that five strains of them were best suitable for high performance cellulose degradation. Determination of CMCA (Sodium Carboxymethylcellulose Activity, CMCA) and FPA (Filter Paper Activity, FPA) had been accomplished for each of the five.The most robust strain screened above was applied to the production of cellulose bioethanol by SHF (Separate Hydrolysis and Fermentation, SHF) and SSF (Simultaneous Saccharification and Fermentation, SSF) with bioethanol productivity of 0.17 g/gDS (Dry Stuff) and 0.076 g/gDS (Dry Stuff) respectively.