Valorization of hydrolysis lignin from a spruce-based biorefinery by applying -valerolactone treatment

Hydrolysis lignin, i.e., the hydrolysis residue of cellulosic ethanol plants, was extracted with the green solvent γ-valerolactone (GVL). Treatments at 170–210 ◦C were performed with either non-acidified GVL/water mixtures (NA-GVL) or with mixtures containing sulfuric acid (SA-GVL). SA-GVL treatment at 210 ◦C resulted in the highest lignin solubilization (64% (w/w) of initial content), and 76% of the solubilized mass was regenerated by water induced precipitation. Regenerated lignins were characterized through compositional analysis with sulfuric acid, as well as using pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS), high-performance size-exclusion chromatography (HPSEC), solid-state cross-polarization/magic angle spinning 13C nuclear magnetic resonance (CP/MAS 13C NMR) spectroscopy, 1 H–13C heteronuclear single-quantum coherence NMR (HSQC NMR), and Fourier-transform infrared (FTIR) spectroscopy. The characterization revealed that the main difference between regenerated lignins was their molecular weight. Molecular weight averages increased with treatment temperature, and they were higher and had broader distribution for SA-GVL lignins than for NA-GVL lignins.publishedVersio

Современные подходы в диагностике и лечении тромбозов системы нижней полой вены

ТРОМБОЗ ВЕНОЗНЫЙ /ДИАГН /ТЕРПОЛАЯ ВЕНА, НИЖНЯЯТРОМБОЭМБОЛИЯЛЕГОЧНАЯ ЭМБОЛИ

Hybrid Aspen Expressing a Carbohydrate Esterase Family 5 Acetyl Xylan Esterase under Control of a Wood-Specific Promoter Shows Improved Saccharification

Fast-growing broad-leaf tree species can serve as feedstocks for production of bio-based chemicals and fuels through biochemical conversion of wood to monosaccharides. This conversion is hampered by the xylan acetylation pattern. To reduce xylan acetylation in the wood, the Hypocrea jecorina acetyl xylan esterase (HjAXE) from carbohydrate esterase (CE) family 5 was expressed in hybrid aspen under the control of the wood-specific PtGT43B promoter and targeted to the secretory pathway. The enzyme was predicted to deacetylate polymeric xylan in the vicinity of cellulose due to the presence of a cellulose-binding module. Cell-wall-bound protein fractions from developing wood of transgenic plants were capable of releasing acetyl from finely ground wood powder, indicative of active AXE present in cell walls of these plants, whereas no such activity was detected in wild-type plants. The transgenic lines grew in height and diameter as well as wild-type trees, whereas their internodes were slightly shorter, indicating higher leaf production. The average acetyl content in the wood of these lines was reduced by 13%, mainly due to reductions in di-acetylated xylose units, and in C-2 and C-3 mono-acetylated xylose units. Analysis of soluble cell wall polysaccharides revealed a 4% reduction in the fraction of xylose units and an 18% increase in the fraction of glucose units, whereas the contents of cellulose and lignin were not affected. Enzymatic saccharification of wood from transgenic plants resulted in 27% higher glucose yield than for wild-type plants. Brunauer-Emmett-Teller (BET) analysis and Simons' staining pointed toward larger surface area and improved cellulose accessibility for wood from transgenic plants compared to wood from wild-type plants, which could be achieved by HjAXE deacetylating xylan bound to cellulose. The results show that CE5 family can serve as a source of enzymes for in planta reduction of recalcitrance to saccharification.Peer reviewe

Downregulation of RWA genes in hybrid aspen affects xylan acetylation and wood saccharification

High acetylation of angiosperm wood hinders its conversion to sugars by glycoside hydrolases, subsequent ethanol fermentation and (hence) its use for biofuel production. We studied the REDUCED WALL ACETYLATION (RWA) gene family of the hardwood model Populus to evaluate its potential for improving saccharification. The family has two clades, AB and CD, containing two genes each. All four genes are expressed in developing wood but only RWA-A and -B are activated by master switches of the secondary cell wall PtNST1 and PtMYB21. Histochemical analysis of promoter:: GUS lines in hybrid aspen (Populus tremula x tremuloides) showed activation of RWA-A and -B promoters in the secondary wall formation zone, while RWA-C and -D promoter activity was diffuse. Ectopic downregulation of either clade reduced wood xylan and xyloglucan acetylation. Suppressing both clades simultaneously using the wood-specific promoter reduced wood acetylation by 25% and decreased acetylation at position 2 of Xylp in the dimethyl sulfoxide-extracted xylan. This did not affect plant growth but decreased xylose and increased glucose contents in the noncellulosic monosaccharide fraction, and increased glucose and xylose yields of wood enzymatic hydrolysis without pretreatment. Both RWA clades regulate wood xylan acetylation in aspen and are promising targets to improve wood saccharification.Peer reviewe

NMR as a tool in drug research : Structure elucidation of peptidomimetics and pilicide-chaperone complexes

In the last decades NMR spectroscopy has become an invaluable tool both in academic research and in the pharmaceutical industry. This thesis describes applications of NMR spectroscopy in biomedicinal research for structure elucidation of biologically active peptides and peptidomimetics as well as in studies of ligand-protein interactions. The first part of this thesis describes the theory and methodology of structure calculations of peptides using experimental restraints derived from NMR spectroscopy. This methodology has been applied to novel mimetics of the peptide hormones desmopressin and Leu-enkephalin. The results of these studies highlight the complicating issue of conformational exchange often encountered in structural determination of peptides and how careful analysis of experimental data as well as optimization of experimental conditions can enable structure determinations in such instances. Although the mimetics of both desmopressin and Leu-enkephalin were found to adopt the wanted conformations, they exhibited no or very poor biological activity. These results demonstrate the difficulties in designing peptidomimetics without detailed structural information of the receptors. A stereoselective synthetic route towards XxxΨ[CH2O]Ala pseudodipeptides is also presented. Such pseudodipeptides can be used as isosteric amide bond replacements in peptides in order to increase their resistance towards proteolytic degradation. The second part of this thesis describes the study of the interaction between compounds that inhibit pilius assembly, pilicides, and periplasmic chaperones from uropathogenic Escherichia coli. Periplasmic chaperones are key components in assembly of pili, i.e. hair-like protein complexes located on the surface of Escherichia coli that cause urinary tract infections. Detailed knowledge about this interaction is important in understanding how pilicides can inhibit pilus assembly by binding to chaperones. Relaxation-edited NMR experiments were used to confirm the affinity of the pilicides for the chaperones and chemical shift mapping was used to study the pilicide-chaperone interaction surface. These studies show that at least two interaction sites are present on the chaperone surface and consequently that two different mechanisms resulting in inhibition of pilus assembly may exist

NMR as a tool in drug research : Structure elucidation of peptidomimetics and pilicide-chaperone complexes

In the last decades NMR spectroscopy has become an invaluable tool both in academic research and in the pharmaceutical industry. This thesis describes applications of NMR spectroscopy in biomedicinal research for structure elucidation of biologically active peptides and peptidomimetics as well as in studies of ligand-protein interactions. The first part of this thesis describes the theory and methodology of structure calculations of peptides using experimental restraints derived from NMR spectroscopy. This methodology has been applied to novel mimetics of the peptide hormones desmopressin and Leu-enkephalin. The results of these studies highlight the complicating issue of conformational exchange often encountered in structural determination of peptides and how careful analysis of experimental data as well as optimization of experimental conditions can enable structure determinations in such instances. Although the mimetics of both desmopressin and Leu-enkephalin were found to adopt the wanted conformations, they exhibited no or very poor biological activity. These results demonstrate the difficulties in designing peptidomimetics without detailed structural information of the receptors. A stereoselective synthetic route towards XxxΨ[CH2O]Ala pseudodipeptides is also presented. Such pseudodipeptides can be used as isosteric amide bond replacements in peptides in order to increase their resistance towards proteolytic degradation. The second part of this thesis describes the study of the interaction between compounds that inhibit pilius assembly, pilicides, and periplasmic chaperones from uropathogenic Escherichia coli. Periplasmic chaperones are key components in assembly of pili, i.e. hair-like protein complexes located on the surface of Escherichia coli that cause urinary tract infections. Detailed knowledge about this interaction is important in understanding how pilicides can inhibit pilus assembly by binding to chaperones. Relaxation-edited NMR experiments were used to confirm the affinity of the pilicides for the chaperones and chemical shift mapping was used to study the pilicide-chaperone interaction surface. These studies show that at least two interaction sites are present on the chaperone surface and consequently that two different mechanisms resulting in inhibition of pilus assembly may exist

Effect of Debarking Water from Norway Spruce (Picea abies) on the Growth of Five Species of Wood-Decaying Fungi

Norway spruce (Picea abies) debarking water is an aqueous extract obtained as waste from the debarking of logs at paper mills. The debarking water contains a mixture of natural compounds that can exhibit diverse biological activities, potentially including fungicidal activity on some species of wood-decaying fungi. Thus, we investigated the growth rates of such fungi on agar plates to which debarking water extracts had been added. The experiment included five wood-decaying fungi, viz. Gloeophyllum sepiarium, Oligoporus lateritius, Ischnoderma benzoinum, Junghuhnia luteoalba, and Phlebia sp. Growth reduction was observed for all species at the highest tested concentrations of freeze-dried and ethanol-extracted debarking water, the ethyl acetate-soluble fraction and the diethyl ether-soluble fraction. However, the magnitude of the effect varied between different species and strains of individual species. The brown-rot fungi G. sepiarium and O. lateritius were generally the most sensitive species, with the growth of all tested strains being completely inhibited by the ethyl acetate-soluble fraction. These results indicate that development of antifungal wood-protecting agents from debarking water could potentially be a way to make use of a low-value industrial waste

Valorization of hydrolysis lignin from a spruce-based biorefinery by applying -valerolactone treatment

Hydrolysis lignin, i.e., the hydrolysis residue of cellulosic ethanol plants, was extracted with the green solvent γ-valerolactone (GVL). Treatments at 170–210 ◦C were performed with either non-acidified GVL/water mixtures (NA-GVL) or with mixtures containing sulfuric acid (SA-GVL). SA-GVL treatment at 210 ◦C resulted in the highest lignin solubilization (64% (w/w) of initial content), and 76% of the solubilized mass was regenerated by water induced precipitation. Regenerated lignins were characterized through compositional analysis with sulfuric acid, as well as using pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS), high-performance size-exclusion chromatography (HPSEC), solid-state cross-polarization/magic angle spinning 13C nuclear magnetic resonance (CP/MAS 13C NMR) spectroscopy, 1 H–13C heteronuclear single-quantum coherence NMR (HSQC NMR), and Fourier-transform infrared (FTIR) spectroscopy. The characterization revealed that the main difference between regenerated lignins was their molecular weight. Molecular weight averages increased with treatment temperature, and they were higher and had broader distribution for SA-GVL lignins than for NA-GVL lignins

Valorization of hydrolysis lignin from a spruce-based biorefinery by applying y-valerolactone treatment

Hydrolysis lignin, i.e., the hydrolysis residue of cellulosic ethanol plants, was extracted with the green solvent γ-valerolactone (GVL). Treatments at 170–210 °C were performed with either non-acidified GVL/water mixtures (NA-GVL) or with mixtures containing sulfuric acid (SA-GVL). SA-GVL treatment at 210 °C resulted in the highest lignin solubilization (64% (w/w) of initial content), and 76% of the solubilized mass was regenerated by water-induced precipitation. Regenerated lignins were characterized through compositional analysis with sulfuric acid, as well as using pyrolysis–gas chromatography/mass spectrometry (Py-GC/MS), high-performance size-exclusion chromatography (HPSEC), solid-state cross-polarization/magic angle spinning 13C nuclear magnetic resonance (CP/MAS 13C NMR) spectroscopy, 1H–13C heteronuclear single-quantum coherence NMR (HSQC NMR), and Fourier-transform infrared (FTIR) spectroscopy. The characterization revealed that the main difference between regenerated lignins was their molecular weight. Molecular weight averages increased with treatment temperature, and they were higher and had broader distribution for SA-GVL lignins than for NA-GVL lignins