Cellulase digestibility of pretreated biomass is limited by cellulose accessibility

Citations Over TimeTop 1% of 2007 papers

Abstract

Attempts to correlate the physical and chemical properties of biomass to its susceptibility to enzyme digestion are often inconclusive or contradictory depending on variables such as the type of substrate, the pretreatment conditions and measurement techniques. In this study, we present a direct method for measuring the key factors governing cellulose digestibility in a biomass sample by directly probing cellulase binding and activity using a purified cellobiohydrolase (Cel7A) from Trichoderma reesei. Fluorescence-labeled T. reesei Cel7A was used to assay pretreated corn stover samples and pure cellulosic substrates to identify barriers to accessibility by this important component of cellulase preparations. The results showed cellulose conversion improved when T. reesei Cel7A bound in higher concentrations, indicating that the enzyme had greater access to the substrate. Factors such as the pretreatment severity, drying after pretreatment, and cellulose crystallinity were found to directly impact enzyme accessibility. This study provides direct evidence to support the notion that the best pretreatment schemes for rendering biomass more digestible to cellobiohydrolase enzymes are those that improve access to the cellulose in biomass cell walls, as well as those able to reduce the crystallinity of cell wall cellulose.

Related Papers

• → Tracking localization and secretion of cellulase spatiotemporally and directly in living Trichoderma reesei(2019)60 cited
• → Simultaneous enhancement of the beta–exo synergism and exo–exo synergism in Trichoderma reesei cellulase to increase the cellulose degrading capability(2019)54 cited
• → Cellulase productivity of Trichoderma reesei mutants developed in Japan varies with varying pH conditions(2019)20 cited
• → Specific quantification of trichoderma reesei cellulases in reconstituted mixtures and its application to cellulase–cellulose binding studies(1994)48 cited
• → Dry action of Trichoderma reesei cellulases on cotton fabrics(2000)