Pseudo reaction kinetics of organic degradation products in dilute-acid-catalyzed corn stover pretreatment hydrolysates

Abstract

A variety of degradation products are produced upon pretreatment of lignocellulosic biomass with dilute acid. To date, the complexity of these samples has significantly limited the scope of efforts to perform summative analyses of degradation products. Qualitative and quantitative interrogation of hydrolysates is also paramount to identifying potential correlations between pretreatment chemistry and microbial inhibition in downstream bioconversion processes. A recently developed reversed-phase high performance liquid chromatography technique with UV detection has been applied to perform quantitative assessments of a variety of hydrolysate components as a function of pretreatment time and temperature. Correlations of product concentrations to the pretreatment severity function indicate differing responses of various compounds to the kinetic influences of temperature and reaction time. Of the compounds measured, four demonstrated initial accumulation rates were sufficiently linear over the time period tested to enable determination of activation energy E(a). All four compounds appear to demonstrate higher E(a) than that assumed in the commonly applied severity function. Overall accumulation trends for most compounds indicated similar under-estimation of apparent activation energy by the severity function. Biotechnol. Bioeng. 2007;98: 1135-1145. (c) 2007 Wiley Periodicals, Inc.

Influence of reaction conditions on the composition of liquid products from two-stage catalytic hydrothermal processing of lignin

“…However, depending on reaction conditions can be estimated from equation (2), which shows its dependence on activated energy as follows [27][28][29];…”

Hemp hurds biorefining: A path to green l-(+)-lactic acid production

“…Increasing the pretreatment harshness, generation of furans and acids, due to degradation of sugars, is often observed (Chen et al, 2007). Because of their well-known toxicity for fermenting microorganisms the presence of these compounds is undesirable.…”

Effect of varying feedstock–pretreatment chemistry combinations on the formation and accumulation of potentially inhibitory degradation products in biomass hydrolysates

“…Investigated feedstocks (i.e., corn stover, poplar, and pine) were chosen to represent major lignocellulosic biomass sources from agricultural residues, hardwood, and softwood, respectively. Eight pretreatment chemistries were investigated: 0.7% H 2 SO 4 , 0.07% H 2 SO 4 (Chen et al, 2007a;Hsu, 1996;Jacobsen and Wyman, 2001;Lloyd and Wyman, 2005), liquid hot water (van Walsum et al, 1996;Weil et al, 1997;Yourchisin and van Walsum, 2004), neutral buffer solution (Mosier et al, 2005b,c), aqueous ammonia (Kim and Lee, 2005;Kim et al, 2000), lime (Blackman and van Walsum, 2008;Chang et al, 1997Chang et al, , 1998Holtzapple, 2005, 2006), lime with oxygen pressurization (Blackman and van Walsum, 2008;Chang et al, 2001), and wet oxidation (Bjerre et al, 1996;Klinke et al, 2002Klinke et al, , 2003.…”