David L. Brink

Identification of potential fermentation inhibitors in conversion of hybrid poplar hydrolyzate to ethanol

In the production of automobile fuel ethanol from biomass by dilute acid hydrolysis/fermentation process, degradation products from the hydrolysis substantially inhibit the bioconversion of sugar to ethanol. Majority of these inhibitors have not been previously identified due to the complexity of biomass hydrolyzate. This paper presents an analytical procedure for identification of biomass degradation products, which entails flash evaporation, anion exchange, chloroform and ethyl acetate extraction, HPLC and GC-MS analyses. More than 35 potential inhibitors to S. cerevisiae fermentation in dilute nitric acid hydrolyzates of hybrid poplar were identified by correlating the fermentability of the anion exchange treated and untreated hydrolyzate samples with their chemical compositions, and by chemical analysis of the regeneration eluate from the ion exchange resin saturated by the hydrolyzate.

The complete analysis of wood polysaccharides using HPLC

Abstract The paper describes an analytical method whereby the chemical composition of the polysaccharide fraction of woody materials, including the uronic acids and carbohydrate acid degradation products, can be completely determined. Sealed vessels, termed bombs, are used during the high temperature acid hydrolysis of the materials to retain volatile constituents that would otherwise be lost. High-Performance Liquid Chromatography (HPLC) is used for all of the analyses. The sample preparation procedures are simple and easily adopted into a routine. To demonstrate the reproducibility of the method, triplicate samples of Quaking aspen ( Populus tremuloides ) and White fir ( Abies concolor ) were analyzed. No significant peaks in the chromatograms were left unidentified.

Simplified Analysis of Acid Soluble Lignin

Abstract The paper describes a novel method for the determination of ultraviolet (UV) light absorptivities for acid soluble lignin (ASL). It was found that the rehydrolysis, or reKlasonation, of Klason lignin continues to release a quantifiable amount of ASL. Thus, previously prepared Klason lignin was repeatedly subjected to reKlasonation and the mass loss after each stage of hydrolysis was quantified. The resulting hydrolysates were satisfactory for determining the absorptivity of ASL at 205 nm. The reKlasonation hydrolysates were found to be spectroscopically identical to hydrolysates prepared from the parent wood species.

Summative Analysis of Nine Common North American Woods

Abstract The summative analysis of lignocellulosic materials has heretofore been a complicated process or the analysis has been incomplete. The Bomb/HPLC summative analysis method presented in this report results in a complete analysis of woody materials using a sample preparation scheme that is easily adopted into a normal laboratory routine. The method relies on HPLC for the majority of the component analyses. To demonstrate the applicability and reproducibility of the Bomb/HPLC method, ten wood samples, from nine different wood species, were analyzed in triplicate and the summative analysis of each sample was effected. The ten woods analyzed were: American beech ( Fagus grandifolia ), Quaking aspen ( Populus tremuloides ), Black cherry ( Prunus serotina ), Sugar (Hard) maple ( Acer saccharum ), Red (Soft) maple ( Acer rubrum ). White ash ( Fraxinus americana ), Yellow birch ( Betula verrucosa ), Douglas fir heartwood and Douglas fir sapwood ( Pseudotsuga menziesii ), and White fir sapwood ( Abies conco...