Correlation analysis of enzymatic digestibility of plant biomass

Abstract

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 analysis was performed and squared correlation coefficients (R 2) were calculated. This analysis showed that hemicelluloses have a negligible impact on enzymatic digestion of the cellulosic component. Content of lignin affected negatively on enzymatic cleavage of cellulose, and namely, an inversely proportional regression between content of lignin in the samples and yield of glucose was observed (R 2 = 0.68). Conversely, increased cellulose content in the biomass affects positively on enzymatic digestion and glucose output (R 2 = 0.90). The best correlation (R 2 = 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 promote enzymatic cleavage of the cellulosic component. The discovered correlation Y = F(X) is a basis of choice the best pretreatment method. In particular, the mild alkaline pretreatment supplemented with bleaching can be a quite efficient method since it provides obtaining the delignified biomass enriched with cellulose that shows an excellent enzymatic digestibility.