Biotehnološka razgradnja i molekularni mehanizmi razgradnje drveta pomoću selektivnih gljiva, uzročnika bijele truleži

Microbial mechanisms of lignin degradation may be utilised for solid-state fermentations other than biopulping, during which the selective conversion of lignin is required. The current paper reviews current work into selective lignin conversion, with emphasis on the contributions made by our research group, which consists of researchers from five different laboratories. Three of them cooperate within Wood K plus. The recent research of this group has focussed on fermentations utilising the unique metabolism of selective white-rot fungi to modify wood surfaces during relatively short fermentation times of less than one week and on research into the molecular mechanisms causing these modifications. Lignin degradation by selective fungi (e.g. Ceriporiopsis subvermispora and species of the genus Phlebia) on the wood surfaces was significant after three days. After seven days the overall lignin content of spruce wood shavings was reduced by more than 3.5 %. Lignin loss was accompanied by an increase of extractable substances. To evaluate small changes and to trace the fungal modification processes, Fourier transform infrared spectroscopic (FTIR) techniques and electron paramagnetic resonance (EPR) spectroscopy were applied and adapted. The spectra recorded in the near infrared region (FT-NIR) turned out to be very useful for kinetic studies of the biopulping/biomodification processes and a good method to evaluate the capabilities of fungi to modify wood surfaces within this short period.Mikrobiološki mehanizmi razgradnje lignina, osim biološke proizvodnje pulpe tijekom koje dolazi do selektivne pretvorbe lignina, mogu se primijeniti tijekom fermentacije na krutoj podlozi. U ovom je revijalnom prikazu dan pregled istraživanja selektivne pretvorbe lignina, a osobito rad znanstvenoga tima, koji se sastoji od istraživača iz pet raznih laboratorija. Troje istraživaa surađuju u centru Wood K plus. Istraživanja te skupine bila su usmjerena na fermentaciju primjenom jedinstvenog metabolizma selektivne gljive, uzročnika bijele truleži, u razgradnji površine drveta tijekom relativno kratkog vremena fermentacije (manje od tjedan dana) i na istraživanje molekularnih mehanizama koji uzrokuju te promjene. Razgradnja lignina s pomoću selektivnih gljiva (npr. Ceriporiopsis subvermispora i vrste roda Phlebia) na površini drveta bila je značajna nakon tri dana. Nakon sedam dana ukupni udjel lignina u piljevini drva smreke smanjen je za više od 3,5 %. Gubitak lignina praćen je povećanjem količine ekstraktibilnih tvari. Da bi se pratio proces modifikacije s pomoću gljiva, primijenjene su prilagođene metode Fourier transformacijske infracrvene spektroskopije (FTIR) i elektronske paramagnetske rezonancije (EPR). Spektar snimljen blizu infracrvenog područja (FT-NIR) bio je vrlo koristan za istraživanje kinetike biološke proizvodnje pulpe odnosno procesa biomodifikacije i dobra je metoda za procjenu sposobnosti gljiva da u vrlo kratkom vremenskom roku razgrađuju površinu drveta

Biotehnološka razgradnja i molekularni mehanizmi razgradnje drveta pomoću selektivnih gljiva, uzročnika bijele truleži

Microbial mechanisms of lignin degradation may be utilised for solid-state fermentations other than biopulping, during which the selective conversion of lignin is required. The current paper reviews current work into selective lignin conversion, with emphasis on the contributions made by our research group, which consists of researchers from five different laboratories. Three of them cooperate within Wood K plus. The recent research of this group has focussed on fermentations utilising the unique metabolism of selective white-rot fungi to modify wood surfaces during relatively short fermentation times of less than one week and on research into the molecular mechanisms causing these modifications. Lignin degradation by selective fungi (e.g. Ceriporiopsis subvermispora and species of the genus Phlebia) on the wood surfaces was significant after three days. After seven days the overall lignin content of spruce wood shavings was reduced by more than 3.5 %. Lignin loss was accompanied by an increase of extractable substances. To evaluate small changes and to trace the fungal modification processes, Fourier transform infrared spectroscopic (FTIR) techniques and electron paramagnetic resonance (EPR) spectroscopy were applied and adapted. The spectra recorded in the near infrared region (FT-NIR) turned out to be very useful for kinetic studies of the biopulping/biomodification processes and a good method to evaluate the capabilities of fungi to modify wood surfaces within this short period.Mikrobiološki mehanizmi razgradnje lignina, osim biološke proizvodnje pulpe tijekom koje dolazi do selektivne pretvorbe lignina, mogu se primijeniti tijekom fermentacije na krutoj podlozi. U ovom je revijalnom prikazu dan pregled istraživanja selektivne pretvorbe lignina, a osobito rad znanstvenoga tima, koji se sastoji od istraživača iz pet raznih laboratorija. Troje istraživaa surađuju u centru Wood K plus. Istraživanja te skupine bila su usmjerena na fermentaciju primjenom jedinstvenog metabolizma selektivne gljive, uzročnika bijele truleži, u razgradnji površine drveta tijekom relativno kratkog vremena fermentacije (manje od tjedan dana) i na istraživanje molekularnih mehanizama koji uzrokuju te promjene. Razgradnja lignina s pomoću selektivnih gljiva (npr. Ceriporiopsis subvermispora i vrste roda Phlebia) na površini drveta bila je značajna nakon tri dana. Nakon sedam dana ukupni udjel lignina u piljevini drva smreke smanjen je za više od 3,5 %. Gubitak lignina praćen je povećanjem količine ekstraktibilnih tvari. Da bi se pratio proces modifikacije s pomoću gljiva, primijenjene su prilagođene metode Fourier transformacijske infracrvene spektroskopije (FTIR) i elektronske paramagnetske rezonancije (EPR). Spektar snimljen blizu infracrvenog područja (FT-NIR) bio je vrlo koristan za istraživanje kinetike biološke proizvodnje pulpe odnosno procesa biomodifikacije i dobra je metoda za procjenu sposobnosti gljiva da u vrlo kratkom vremenskom roku razgrađuju površinu drveta

Solute interactions in the nanofiltration of wood hydrolysates

Spent sulfite liquor derived from sulfite pulping is considered as carbon source for bio-based platform chemicals. The spent sulfite liquor containing sugars, hydroxylic acids, furan derivatives and cooking chemicals is currently predominantly combusted to generate energy and to recover the pulping chemicals. In order to improve the economic performance of the whole pulping process a partial material use of the spent sulfite liquor is desirable. The lignosulfonates can be separated by ultrafiltration and be used as concrete plasticizer or as source for phenolic-based hydrogels or performance materials. The carbohydrates and other wood degradation products can be used as energy and carbon source in a fermentation process. In order to improve the fermentation process, the amount of inhibitory compounds, such as furan derivatives and short-chain organic acids needs to be reduced. Intermolecular interactions between different molecules influence the detoxification process by means of nanofiltration. The lignosulfonate interacts with inhibitor components and increase their retention, which is unfavorable for the process efficiency. The interactions between gluconic acid and short-chain organic acids were found to increase the membrane selectivity.MoV4-(01) page 1MoV4-(01) page 4

CHARACTERIZATION OF KEY PARAMETERS FOR BIOTECHNOLOGICAL LIGNOCELLULOSE CONVERSION ASSESSED BY FT-NIR SPECTROSCOPY. PART II: QUANTITATIVE ANALYSIS BY PARTIAL LEAST SQUARES REGRESSION

Wheat straw (Triticum aestivum L.) and oat straw (Avena sativa L.) were chemically pretreated at different severities with the purpose of delignification, which in turn leads to a better accessibility of plant cell wall polysaccharides for further biotechnological conversion. Key parameters of these samples, i.e. weight loss, residual lignin content, and hydrolysable sugars serving as precursors for biofuel production were monitored by wet-chemistry analyses. Fourier transform near infrared (FT-NIR) spectra were correlated to these data by means of partial least-squares (PLS) regression. Weight loss (4.0 – 33.5%) of the wheat straw could be predicted (RMSEP = 3.5%, R²test = 0.75) from the entire FT-NIR spectra (10000 – 4000 cm-1). Residual lignin content (7.9 – 20.7%, RMSEP = 0.9%, R²test = 0.94) and amount of reducing sugars based on pretreated wheat straw (128 – 1000 mg g-1, RMSEP = 83 mg g-1, R²test = 0.89) were powerfully evaluated between 6900 and 5510 cm-1, a spectral region where polysaccharides and lignin absorb. All these parameters could be equally predicted with even higher accuracy from pre-treated oat straw samples. Furthermore, some important parameters for anaerobic conversion of wheat straw to biogas – biogas production, total solids, and volatile solids content – could be estimated

Equilibrium wage dispersion, firm size and growth

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A combined view on composition, molecular structure, and micromechanics of fungal degraded softwood

Fungal decay alters the composition, microstructure, and mechanical properties of wood cell walls. To understand better the structure-function relationships during fungal decay, selected annual rings of fungal deteriorated Scots pine sapwood were analyzed in terms of their composition, microstructure, and micromechanical properties. The datasets were acquired separately for earlywood and latewood concerning the S2 cell wall layer and the cell corner middle lamella (CCML) and analyzed by means of principal component analysis and partial least squares regression analysis. Links between cell wall stiffness and hardness and the composition and microstructure could be established. Increased mechanical properties in the CCML, as obtained by nanoindentation, were correlated to the degradation of pectins. In the S2 layer, the altered data were related to the degradation of hemicelluloses and lignin modification during fungal decay