Study On Photocatalytic/KOH Pretreatment Of Corncob And Its Enzymatic Hydrolysis

At present,the energy is gradually exhausted,but the demand is growing,and the contradiction between the two is becoming more and more prominent.How to develop and utilize renewable,new and clean energy has become the focus of attention.As a typical representative of renewable energy,biomass energy is the focus of current research.Lignocellulose,as a biomass resource from a wide range of sources,has been proved to be further used as fermented sugar,but its complex internal structure reduces the efficiency of enzymatic hydrolysis and saccharification and increases its pretreatment cost.Therefore,the development of efficient pretreatment technology in order to improve the enzymatic hydrolysis and saccharification effect of lignocellulose has become the focus of research in this field.In this paper,photocatalysis was introduced into the pretreatment process of lignocellulose.Using corncob as raw material,the following studies were carried out:（1）The photocatalytic pretreatment of corncob was investigated.P25 Ti O₂with good photocatalytic effect was selected as the photocatalyst under 254 nm UV light source,and activated carbon（0.5 g）was introduced as the catalyst.Through single factor test and response surface optimization,the optimal conditions of photocatalytic pretreatment stage are obtained,that is,the dosage of Ti O₂is 0.6 g/L,the material liquid ratio is 1:40,and the photocatalytic time is 45 min.（2）The alkali treatment stage of corncob was investigated.It was found that the optimum temperature,KOH dosage and alkali treatment time were 50 ^oC,4%and 90 min respectively.Through cellulase hydrolysis and saccharification,taking the yield of glucose as the measurement index,it was found that under the optimal enzymatic hydrolysis conditions（5%solid content,20 FPU/g-substrate）,the highest yield of glucose was 97.82±1.1%,and the removal rate of lignin was85.3%.（3）FTIR,XRD and SEM were used to analyze the morphology of corncob before pretreatment,corncob after KOH pretreatment and corncob after photocatalytic/KOH pretreatment.It can be concluded that the crystallinity（CRI）of corncob after photocatalytic/KOH pretreatment increased and the intensity of characteristic peak of corncob after pretreatment changed;Compared with raw materials and KOH treated corncobs,lignin in the corncobs pretreated with light assisted KOH was largely removed in the pretreatment process,and the connection between various components was destroyed to a great extent;The surface porosity and porosity of corncob pretreated with light assisted KOH were greatly increased by SEM.This fully shows that the corncob pretreated with photocatalysis assisted KOH is more conducive to the later enzymatic hydrolysis and saccharification than the raw material and KOH treated corncob.