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The process sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL) has been the focus of this study. Pilot-scale (50 kg) pretreatment of wood chips of lodgepole pine ( Pinus contorta Douglas ex Loudon) killed by mountain pine beetle ( Dendroctonus ponderosae Hopkins) were conducted at 165°C with a dilute sulfite solution of pH 2 for bioconversion to ethanol and lignosulfonate (LS). The pretreatment duration was optimized in laboratory bench scale experiments with a certain severity based on a combined hydrolysis factor (CHF). The sodium bisulfite loading was 8% and the liquor to wood ratio 3. The pretreated solids were disk milled together with the spent liquid and the resultant slurry with a 25% solids content was directly (without detoxification) submitted to a simultaneous enzymatic saccharification and fermentation (SSF) with Saccharomyces cerevisiae YRH400 at cellulase loading of 35 ml kg-1 of untreated wood. At solids loading of 20%, the alcohol yield was 288 l t-1 wood (with a final concentration of 52.2 g l-1), which corresponds to a 72.0% theoretical yield based on total glucan, mannan, and xylan. The LS from SPORL was highly sulfonated and its molecular weight was lower than that of a purified commercial softwood LS, and therefore it has a high potential as a directly marketable co-product. [ABSTRACT FROM AUTHOR]

The effects of lignosulfonate (LS) on enzymatic saccharification of pure cellulose were studied. Four fractions of LS with different molecular weight (MW) prepared by ultrafiltration of a commercial LS were applied at different loadings to enzymatic hydrolysis of Whatman paper under different pH. Using LS fractions with low MW and high degree of sulfonation can enhance enzymatic cellulose saccharification despite LS can bind to cellulase nonproductively. The enhancing effect varies with LS properties, its loading, and hydrolysis pH. Inhibitive effect on cellulose saccharification was also observed using LS with large MW and low degree of sulfonation. The concept of 'LS-cellulase aggregate stabilized and enhanced cellulase binding' was proposed to explain the observed enhancement of cellulose saccharification. The concept was demonstrated by the linear correlation between the measured amount of bound cellulase and saccharification efficiency with and without LS of different MW in a range of pH. [ABSTRACT FROM AUTHOR]

Lignosulfonates(LSs), by-products from chemical pulping processes, are low-value products with limited dispersion properties. The ability of commercially available horseradish peroxidase (HRP) to polymerize LS macromolecules and improve the dispersion properties of LSs was investigated. The polymerization of LSs proceeded efficiently under mild reaction conditions in an aqueous solution with HRP/H 2O 2. Gel permeation chromatography showed a significant increase in weight-average molecular weight ( Mw) of sulfonated kraft lignin and sodium lignosulfonate (NaLS) by 8.5-fold and 4.7-fold, respectively. The mechanism of polymerization was investigated by elemental analysis, surface charge measurement, headspace gas chromatography, infrared spectroscopy (IR), and hydrogen nuclear magnetic resonance spectrometry ( 1H-NMR). The functional group measurements indicated that HRP incubation did not reduce the sulfonic group content. However, it decreased the phenolic and methoxyl group contents. As the phenolic group content decreased, Mw increased as a power function. The polymerization was proposed to involve the random coupling of phenoxy radical intermediates. The radicals coupled with each other to form different inter-unit linkages, most of which were the β-O-4’ type, as the 1H-NMR spectra indicated. Moreover, the HRP/H 2O 2 incubation induced a significant improvement in the adsorption and dispersion properties of LSs. Therefore, the HRP/H 2O 2 incubation is a promising approach for industrial applications of LSs. [ABSTRACT FROM AUTHOR]

Thisstudy conducted an investigation of the effect of lignosulfonate(LS) on enzymatic saccharification of lignocelluloses. Two commercialLSs and one laboratory sulfonated kraft lignin were applied to Whatmanpaper, dilute acid and SPORL (sulfite pretreatment to overcome recalcitranceof lignocelluloses) pretreated aspen, and kraft alkaline and SPORLpretreated lodgepole pine. All three lignin samples inhibited cellulosesaccharification of Whatman paper, but enhanced the saccharificationof the four lignocellulosic substrates. The level of enhancement wasrelated to the molecular weight and degree of sulfonation of the ligninas well as the substrate lignin structure. When different molecularweight (MW) fractions of one commercial LS (SXP), generated from sulfitepulping of hardwood, were applied to the Whatman paper, the largeMW fraction (SXP1) with the lowest degree of sulfonation inhibitedcellulose saccharification while the intermediate (SXP2) and smallest(SXP3) MW fractions enhanced saccharification. All MW fractions enhancedsaccharification of the four lignocellulosic substrates with maximalenhancement by the smallest MW fraction, SXP3. The enhancement wasmost significant for the kraft lodgepole pine substrate and leastsignificant for the SPORL pretreated lodgepole pine using all threeLS and SXP fractions. The results suggest that LS acts as a surfactantto enhance pure cellullose saccharification. When LS is applied tolignocelluloses, it acts as a surfactant to block bound lignin frombinding cellulase nonproductively leading to enhanced saccharification. [ABSTRACT FROM AUTHOR]

The ability of commercial laccase for improvement of the physicochemical properties of sodium lignosulfonate (NaLS) without any mediator has been investigated. Surface tension, adsorption characteristics, rheological behaviors and fluidity of cement pastes were in focus. Gel permeation chromatography (GPC) shows an initial decrease and then an extensive increase of molecular weight (MW) of NaLS after incubation with laccase. Parallel to MW decrement, the content of phenolic groups is increasing, while an MW increment has the opposite effect. The UV-Vis spectra and the zeta potential of NaLS do not indicate further modification of the substitution pattern on the aromatic ring. The surface tension of NaLS and the adsorbed amount of NaLS on MgO particles is elevated after laccase treatment. The electrostatic attraction between MgO particles and NaLS is the main driving force during this adsorption process. The dispersion efficiency of laccase modified NaLS on the MgO slurry and cement paste is improved. [ABSTRACT FROM AUTHOR]

Abstract: The solution behavior of purified sodium lignosulfonate (PSL) at different pH values were investigated by means of acid–base titration, surface tension, viscosity, fluorescence spectrometry, dynamic light scattering (DLS) and environmental scanning electron microscopy (ESEM) experiments. Fluorescence experiments showed that the critical aggregate concentration (CAC) of PSL was 0.05g/L. DLS results indicated that the average dimension of PSL molecule and PSL aggregate was about 8nm and 80nm, respectively. The surface charge of PSL molecules and the aggregation degree of PSL in solution increased with the increasing of pH due to the ionization of sulfonic and phenolic hydroxyl groups. The size of PSL aggregates and reduced viscosity of PSL solution increased as pH values increased because expansion of the PSL cores. A model for the assembly behavior of PSL was first proposed to explain the influence of pH on the molecular configuration and aggregation behaviors of lignosulfonate in aqueous solutions. [ABSTRACT FROM AUTHOR]