Advances in genetics, engineering, and biotechnology, the diminishing supply of fossil fuel as well as growing concerns about environmental stewardship are leading to a new concept for converting renewable biomass to biofuels. However, current bioconversion of biomass to biofuels is significantly hindered by the innate recalcitrance of biomass which refers to the characteristics of lignocellulose to protect its carbohydrates from enzyme degradation. Pretreatment is known to overcome biomass recalcitrance to some extent by increasing cellulose accessibility which has been proposed as a key factor in the efficient bioconversion of lignocellulosic biomass to fermentable sugars. In this study, multiple analytical techniques including Simons' stain, mercury porosimetry, and several NMR based techniques were utilized to measure the cellulose accessibility of various dilute acid, hot water, and alkaline pretreated of Populus. Results indicate that pretreatment significantly increases cellulose accessibility so that appreciable amounts of enzyme have access to cellulose, and as pretreatment severity is increased so does cellulose accessibility. Despite the fact that each pretreatment has its own mechanism, dilute acid is determined to be one of the most effective pretreatment in terms of cellulose accessibility increase. This work was done in an effort to generate a more accurate description of cellulose accessibility via multiple surface area/porosity measurement techniques, further test the changes in the accessibility of lignocellulosic substrate upon pretreatment, and correlate the cellulose accessibility change to the enzymatic hydrolysis results, thus yielding a better understanding of fundamental biomass recalcitrance especially the role of cellulose accessibility.

Recent progress in understanding the role of cellulose accessibility in biomass recalcitrance

247th National Meeting (2014)

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