Full Utilization Of Lignocellulose Based On Acid Hydrotrope

The full utilization of a large-volume,renewable and environmentally friendly lignocellulose can help solve the problem of depletion of fossil fuels and environmental pollution that humans are currently facing.In this study,different lignocelluloses were pretreated and classified by acid hydrotrope(p-toluenesulfonic acid),achieving the resource utilization of each component.The main findings are as follows:(1)The effects of p-toluenesulfonic acid concentration,pretreated temperature and time on the composition and enzymatic hydrolysis rate of the wheat straw.Simultaneously,we explored the applicability of this pretreatment method to lignocellulose from different sources and characterized the structure of the pretreated materials.Therefore,we can conclude the optimal pretreatment conditions for the wheat straw(acid concentration 70%,temperature 80 °C,time 10 min).Under these conditions,the removal rate of lignin and hemicellulose were 78.0% and 71.0%,respectively.Importantly,cellulose achieved a 92.0% retention.If the pretreatment conditions are applied to corncobs,miscanthus and jujube,the different hemicellulose removal rates(79.38%,60.67%,and 73.29%),lignin removal rates(69.34%,46.41%,and 39.54%),retention rates of the cellulose(89.51%,104.4%,and 99.75%)were obtained.This indicates that the pretreatment of p-toluenesulfonic acid can selectively remove lignin and hemicellulose to obtain a cellulose-rich pretreatment material.On the whole,p-toluenesulfonic acid realize different pretreatment effects on four different biomass sources(corncobs > wheat straw > miscanthus > jujube).(2)We studied the influence of pretreatment raw material cellulase hydrolysis from cellulase addition,buffer solution pH and substrate concentration.The effects of simultaneous saccharification and quasi simultaneous saccharification fermentation on ethanol yield of different pretreated feedstocks were compared.The results indicated the optimal enzymatic hydrolysis conditions of corncobs,wheat straw,miscanthus and jujube(pH 5.6,cellulase addition 15 FPU/g dextran,substrate concentration 2%).At this time,the enzymatic hydrolysis rates of the four pretreated biomasses were 96.25%,94.46%,85.29%,and 40.37%,respectively.At 96 h,the ethanol concentrations of corncob,wheat straw and miscanthus through simultaneous saccharification and fermentation were 45.5 g/L,35.0 g/L and 30.5 g/L,respectively,which is equivalent to the theoretical yield of ethanol produced from untreated lignocellulose 72.14%,57.16%,61.37%.The ethanol concentrations of corncob,wheat straw and miscanthus through quasi simultaneous saccharification and fermentation were 55.0 g/L,37.5 g/L,and 34.5 g/L,respectively,which is equivalent to the theoretical yield of ethanol produced from untreated lignocellulose 87.86%,61.71%,and 69.42%.Therefore,the quasi simultaneous saccharification and fermentation method is superior to the simultaneous saccharification and fermentation.(3)We studied the recovery of lignin in waste liquid,and then investigating the size and structure of the particle to provide a theoretical basis for the utilization of lignin.In addition,the recycling of p-toluenesulfonic acid was also studied.The results demonstrated that the recovery of lignin reached 80.76% and the purity was 94.74% when the concentration of ptoluenesulfonic were diluted to 4%.The size,surface morphology and controllability of the lignin nanoparticles obtained from dilution precipitation method were investigated by the atomic force microscopy.When the centrifugal force increased from 3000 g to 15000 g,the average size of the lignin nanoparticles is decreased from 200 nm to 50 nm,indicating that the size and uniform distribution of the lignin nanoparticles can be controlled by different centrifugal force conditions.In addition,the acid-hydrotrope(p-toluenesulfonic acid)has good reusability.