Organosolv delignification of white- and brown-rottedEucalyptus grandis hardwood

Abstract

Sound (undecayed control) and fungally-pretreated wood samples were submitted to organosolv deligni®cation. The cooking liquor used was methanol/water (78:22 v/v) containing CaCl 2 and MgSO 4 each at a concentration of 25 mmol dm À3. The cooking process was performed at 180°C for reaction times varying from 5 to 100 min. Despite some differences in the lignin removal pattern, pseudo-®rst order kinetic models permitted a prediction of deligni®cation rate constants for all experiments. All biodegraded samples provided higher deligni®cation rate constants than the undecayed control (2.0 Â 10 À2 min À1 for the undecayed control and, for example, 14.2 Â 10 À2 min À1 for the sample decayed by Trametes versicolor for 2.5 months). Biodegraded samples also presented signi®cantly increased xylan removal rates. The type of biodegradation affected the behavior of wood samples under organosolv pulping. The highest deligni®cation and xylan removal rate constants were observed in the sample decayed by T versicolor for 2.5 months (17% weight loss). However, high deligni®cation and xylan removal rate constants were also observed in the sample decayed by Punctularia artropurpurascens for only 0.5 months (1.2% weight loss). Data obtained from a single fungal species pretreatment or data from all fungal pretreatments indicated that there is no clear correlation between the deligni®cation constants and the wood weight or component losses. This lack of correlation suggested that the structure of residual polymers in decayed wood affects the deligni®cation process in the organosolv pulping more than the removal extent of each individual component.

Investigating Lignocellulose in Cornstalk Pretreated with Trametes pubescens Cui 7571 to Improve Enzymatic Saccharification

“…Among the three fungi, xylanase activity varied from 25.83 to 56.71 U/mg during the 8-week period. The recorded xylanase activities were consistent with the findings of Ferraz et al (2000), who reported that various organisms use hemicellulose as a carbon source without breaking lignin. Trametes pubescens Cui 7571 showed significant laccase activity from week 6 onwards, which was the highest on week 8 (0.17 U/mg).…”

Crescimento inicial de Jatropa curcas L. sob doses de fósforo e deriva de glyphosate

“…Determinou-se também o conteúdo de lignina, celulose e teor de fósforo foliar, de acordo as metodologias propostas por Ferraz et al, (2000), Santos (2000) e Tedesco et al, (1995), respectivamente.…”

Near‐Infrared Spectra and Chemical Characteristics ofPinus taeda(Loblolly Pine) Wood Chips Biotreated by the White‐Rot FungusCeriporiopsis subvermispora

“…Regression models relating other compositional properties or macromolecular characteristics shown in Table 1 with NIR spectral data were statistically insignificant or presented poor capabilities to predict experimental values determined by wet chemical analysis. [2,5,6] Decreases in aryl-ether linkage contents correlate well with the reduced lignin contents of bio-kraft Ferraz et al 106 pulps, whereas the degree of polymerization of the a-cellulose can potentially be critical with respect to the strength properties of the biopulps. [17] Correlations of NIR bands with a-cellulose degree of polymerization or aryl-ether linkage contents in lignin are a useful feature of NIR spectroscopy for monitoring wood biodegradation.…”