Sunday, May 4, 2008
3-31
The Effect of Ultrasonic Irradiation on Physical Characteristics and Saccharification of Concentrated Biomass Slurries
Samin Rezania and R. Eric Berson. Chemical Engineering, University of Louisville, J.B. Speed School of Engineering, Chemical Engineering Department, Belknap Campus, Louisville, KY 40292
Biomass is converted to ethanol as the result of several processing steps of which enzymatic hydrolysis (saccharification) is a key rate and cost limiting step. To achieve the most economically feasible conversion of solids to glucose through saccharification of biomass, improvements are needed for this step. It is desirable to begin with a high solids concentration in order to maximize the product concentration in the sugar stream, minimize water and energy use, and minimize reactor volume. However, when processing with concentrated slurries, high viscosity prevents efficient mixing and leads to reduced conversion. Previous results show higher saccharification rates with smaller particle sizes. Therefore, the first aim of this study was to determine if the particle size of biomass can be further reduced using ultra-sonication.
Results show that ultrasonic irradiation is effective in reducing the particle size of substrates used in this work in terms of both particle size distribution and average particle size of the substrate. Average particle sizes were reduced to as low as 1 micron under the conditions tested. The effect of reduced particle sizes on saccharification rates and rheological properties (viscosity) of biomass slurries are presented. While saccharification rates increased, the viscosity of slurries with particles in this size range surprisingly did not follow the same trends as observed for bigger sizes ranges due to surface characteristics of the particles are presented here. This work also characterizes changes in physical characteristics such as crystallinity caused by ultrasonic irradiation and examines how those changes affect enzymatic digestibility.
Results show that ultrasonic irradiation is effective in reducing the particle size of substrates used in this work in terms of both particle size distribution and average particle size of the substrate. Average particle sizes were reduced to as low as 1 micron under the conditions tested. The effect of reduced particle sizes on saccharification rates and rheological properties (viscosity) of biomass slurries are presented. While saccharification rates increased, the viscosity of slurries with particles in this size range surprisingly did not follow the same trends as observed for bigger sizes ranges due to surface characteristics of the particles are presented here. This work also characterizes changes in physical characteristics such as crystallinity caused by ultrasonic irradiation and examines how those changes affect enzymatic digestibility.
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See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)
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See more of The 30th Symposium on Biotechnology for Fuels and Chemicals (May 4 -- 7, 2008)