| Corncob is the by-product of agriculture which is rich in cellulose,hemicelluloses and lignin.But a lot of Corncob have been incinerated and buried like rubbish.It is not only waste of resource,but also polluting the environment.Beacause of the requirement of us to energy is more and more,the traditional resource like petroleum and fossil energy are no-renewable resourse.The resource may will be exhausted in the future.So how to relax energy crisis is the topic of every nations’develop have to face.Using Corncob cellulose as the raw material to product bioethanol in the industry,which is a effective way to relax energy crisis,and it is also a hot topic in research of every country.For prove the efficiency of degrading Corncob cellulose,surfactant as a auxiliaries-which is commn in industry-catching humans’ eyes.Some possibility from scholars have been proposed:(i)surfactants might act on the cell membrane causing release of enzymes;(ii)surfactants may increase enzyme stability and prevent denaturation of enzymes during hydrolysis;(iv)surfactants may reduce the unproductive enzyme that adsorb on the lignin part of the substrate.The purport of this research is discuss The effect of surfactant in the One-step Fermentation with Corncob.Lay a foundation to corncob for practical application.The first of our study is to research the effect of three kinds of surfactants-Tween 80,Rhamnolipid,Tea saponin-in the culture of S.cerevisiae.Adding different concentration of these three kind of surfactants to YPD medium respectively.The result show that Tween 80 with the concentration of 0.1%and 0.2%will be avail to the culture before 20h.When cultivate for 40h,the value of OD600 which Tween 80 have been add are reach 6.0,the same as the contrct.Rhamnolipid with the concentration of 0.05%show little in the culture.But following the increasing of the concentration,Rhamnolipid restraining the culture.When cultivate for 40h,the value of OD600which 0.8%Rhamnolipid have been add is 10%lower than the contrast.Tea saponin with the concentration of 0.002%show little in the culture.But following the increasing of the concentration,Tea sapon inrestraining the culture intensely.When cultivate for 40h,the value of OD600which 0.01%Tea saponin is only 0.35.The result show us that 0.1%Tween 80,0.05%Rhamnolipid,0.002%Tea saponin is the best condition for the cultivation of saccharomy cescerevisiae.Base on previou research,study the effect of three kinds of surfactants in the shake flask fermentation with Corncob as the sole carbon soure.Respectively,add 0.1%Tween 80,0.05%Rhamnolipid,0.002%Tea saponin to the medium which corncob as the sole carbon sourse.Inoculatethe recombinant S.cerevisiae integrated three cellulase respectively were screened by auxotrophic selection medium(INVSc-SE,integrated endoglucanase gene eg;INVSc-SC,integrated exoglucanase gene cbh;INVSc-SB,integrated β-glucosidase gene bg)in the medium.INVSc-SE,INVSc-SC and INVSc-SB are mixed with equal part before integrating.Both the reducing sugar and biomass in the medium which have surfactants are more than the contract.When cultivate for 120h,in the medium which with 0.1%Tween 80,respective,the reducing sugar and biomass is3.88%and 10.87%higher than the contrast;When cultivate for 120h,in the medium which with 0.05%Rhamnolipid,respective,the reducing sugar and biomass is18.26%and 5.43%higher than the contrast;When cultivate for 120h,in the medium which with 0.002%Tea saponin,respective,the reducing sugar and biomass is 8.21%and 3.26%higher than the contrast.The result show that,in the shake flask fermentation with Corncob as the sole carbon soure,0.1%Tween 80,0.05%Rhamnolipid,0.002%Tea saponin is not only avail to the degradation of Corncob cellulose but also the culture.Furthermore,researched the change of microstructure in the degradation of corncob.In microstructure,corncobs is like a long bundlenets in the begin and like a cloth or granule,revealed the hydrolysed process of corncobs. |
