Study of the enzymatic activity inhibition on the saccharification of acid pretreated corn stover

The inhibition of the enzymatic saccharification of acid pretreated corn stover (PCS) biomass due to several compounds either present in PCS or produced during saccharification has been studied. The prospective inhibitors tested were glucose (≤110 g L-1), celobiose (≤24 g L-1), xylose (≤50 g L-1), arabinose (≤1.5 g L-1), furfural (≤2 g L-1), hydroxymethylfurfural (≤1 g L-1), acetic acid (≤4 g L-1), and lignin (≤50 g L-1). Each of these compounds was added at three different concentrations, being the concentration intervals different according to standard maximum concentrations of such compounds in the reaction medium, previously measured and described in literature. In addition, these experiments were employed to evaluate the standard error present during the evaluation of the results obtained in the inhibition reactions. Those results show that significant inhibition was only detected for lignin (more than 25 g L-1) and it was also appreciable for glucose at high concentrations (above 75 g L-1), although it was not remarkable at medium concentrations (40 g L-1). On the other hand, neither of the remaining compounds tested presented any significant inhibitory effect at the usual process concentration range.