Biological processing of cellulosic biomass to fuels and chemicals would open up major new agricultural markets and provide powerful societal benefits, but pretreatment operations essential to economically viable yields have a major impact on costs and performance of the entire system. However, little comparative data is available on promising pretreatments. To aid in selecting appropriate systems, leading pretreatments based on ammonia explosion, aqueous ammonia recycle, controlled pH, dilute acid, flowthrough, and lime were evaluated in a coordinated laboratory program using a single source of corn stover, the same cellulase enzyme, shared analytical methods, and common data interpretation approaches to make meaningful comparisons possible for the first time. Each pretreatment made it possible to subsequently achieve high yields of glucose from cellulose by cellulase enzymes, and the cellulase formulations used were effective in solubilizing residual xylan left in the solids after each pretreatment. Thus, overall sugar yields from hemicellulose and cellulose in the coupled pretreatment and enzymatic hydrolysis operations were high for all of the pretreatments with corn stover. In addition, high-pH methods were found to offer promise in reducing cellulase use provided hemicellulase activity can be enhanced. However, the substantial differences in sugar release patterns in the pretreatment and enzymatic hydrolysis operations have important implications for the choice of process, enzymes, and fermentative organisms.
[1]
N. Mosier,et al.
Optimization of pH controlled liquid hot water pretreatment of corn stover.
,
2005,
Bioresource technology.
[2]
Y. Y. Lee,et al.
Pretreatment of corn stover by soaking in aqueous ammonia
,
2005,
Applied biochemistry and biotechnology.
[3]
Jun Seok Kim,et al.
Pretreatment of corn stover by low-liquid ammonia recycle percolation process
,
2006,
Applied biochemistry and biotechnology.
[4]
M. Holtzapple,et al.
Lime pretreatment and enzymatic hydrolysis of corn stover.
,
2005,
Bioresource technology.
[5]
Farzaneh Teymouri,et al.
Ammonia fiber explosion treatment of corn stover
,
2004,
Applied biochemistry and biotechnology.
[6]
Charles E Wyman,et al.
Partial flow of compressed-hot water through corn stover to enhance hemicellulose sugar recovery and enzymatic digestibility of cellulose.
,
2005,
Bioresource technology.