Synergistic Fermentation Of Camphor Leaves Cellulose And Technology Research Of Ethonal Production

At present,the renewable carbon sources such as lignocellulosic biomass,have became an alternative energy source and has been widely used for biorefinary.Lignocellulosic biomass use for the production of biofuels relies on the enzymatic hydrolysis of pretreated biomass to produce reducing sugars.A set of enzymes required for synergistic lignocellulosic biomass conversion includes cellobiohydr-olases,endoglucanases,beta-glucosidases.One of the major bottlenecks is the cost of enzymes for enzymatic hydrolysis.The potential solution is the on-site production of these enzymes in order to minimize the expenses of enzymes addition.It has a important prospect of application to use the synergy of microbes to produce high efficient cellulase system for lignocellulose bioconversion to biofuels and chemical products.The present study used highly productive cellulolytic fungus as starting strains,to screen an coculture system for efficiently cellulose conversion,and optimization of the fermentation conditions to furtherly study the effects in the bioethanol ferme-ntation.The main results of this paper are as following:1.Used three cellulolytic fungus of Penicillium decumbens,Aspergillus niger C112,and Trichoderma reesei RutC-30 with high-yield cellulase as the starting strains,to screen for the best combination and proportion of synergistic fermentation.The best combination of strains was confirmed as T.reesei RutC-30 and P.decumbens with an 8:2 inoculum ratio.The maximum sugar concentration was 1.48 g/L,higher than that of reducing sugar concentration(0.48 g/L)of monoculture.2.Used single factor combined Box-Behnken designs to optimize the conditions of synergistic fermentation by T.reesei RutC-30 and P.Decumbens,and the optimum fermentation conditions is:a substrate concentration of 5.9%,temperature of 32.1?,fermentation of 5.8 d at an initial pH of 6.5.Under these conditions,a predicted reducing sugar production is 2.91 g/L,and an actual sugar concentration is 2.96 g/L through validation,was 2 times before optimization.3.Based on the optimization results of synergistic fermentation by T.reesei RutC-30 and P.Decumbens,used separate hydrolysis fermentation to study and optimize the conditions of cellulosic ethanol fermentation,and the best fermentation parameters as follows:nitrogen sources for added 1.4 g yeast extract,inoculum with 9%of angel yeast,fermentation time of 40 h,the ethanol yield of 1.41 mg/mL was obtained under these conditions.4.Simultaneous saccharification fermentation by difference combination and proportion of cellulolytic fungus of P.decumbens,A.niger C112,and T.reesei RutC-30 combined angel yeast were disscussed.The best combination of strains was confirmed as A.niger C112 and T.reesei RutC-30 with an 1:9 inoculum ratio.the optimal fermentation parameters as follows:Camphor tree leaves of 12%,temperature of 31.6?,initial pH of 5.9,under these conditions,the ethanol yield is 7.22 mg/mL.