Abstrato

Effect of chemical composition of plant biomass on enzymatic hydrolysis

Michael Ioelovich

Enzymatic hydrolysis of a large number of not-treated and pretreated biomass samples of various origins containing different amounts of cellulose, hemicelluloses and lignin has been studied.To disclose the effect of individual polymeric components on yield of glucose, a correlation analysiswas performed and squared correlation coefficients (R2)were calculated. This analysis showed that hemicelluloses have a negligible impact on enzymatic digestion of the cellulosic component. Content of lignin affected negatively on enzymaticcleavageofcellulose,andnamelyaninversely proportional regression between content of ligninin the samples and yield of glucosewas observed (R2=0.68). Conversely, increased cellulose content in the biomass affects positively on enzymatic digestion and glucose output (R2 = 0.90). The best correlation (R2 = 0.98) was found for the dependence of glucose yield (Y) on difference between contents of cellulose and lignin (X) in the investigated biomass samples. Thus, increasing the content of cellulose and decreasing the content of lignin in the samples promotes enzymatic cleavage of the cellulosic component.The discovered correlation Y=F(X) is a basis of choice the best pretreatment method. In particular, themild alkaline pretreatment supplementedwith bleaching can be a quite efficient methodsinceit providesobtainingthedelignified biomass enrichedwith cellulose that shows an excellent enzymaticdigestibility.