Degradation Products Formed in Physicochemical Pretreatment of Lignocellulose Biomass and Their Influence on the Effectivity of the Ethanol Production Process

Abstract

Prior to its use as feedstock in ethanol production, lignocellulose biomass must be decomposed and hydrolysed. In mild physicochemical pretreatment a wide range of degradation products such as organic acids, furan derivatives or phenolic compounds are formed, which can act as inhibitors. The inhibitors can affect the activity of cellulolytic enzymes and the metabolism of microbial cells and thus decrease the conversion of cellulose to fermentable sugars and the efficiency of ethanol production. The effect of individual compounds on the commercially available enzymes, yeasts and bacterial strains employed in ethanol production together with the inhibition mechanism is discussed. Several strategies to minimize the inhibitory effect such as physical, chemical or biological detoxification of hydrolysates or the use of strains tolerant to inhibitors are discussed.