FTIR spectroscopic prediction of Klason and acid soluble lignin variation in Norway spruce cutting clones

Abstract

Our purpose was to develop a FTIR spectroscopic method to be used to determine the lignin content in a large number of samples and to apply this method studying variation in sapwood and heartwood lignin content between three fast-growing cutting clones grown in three sites. Models were estimated with 18 samples and tested with 6 samples for which the Klason lignin + acid soluble lignin content had been determined. Altogether 272 candidate models were built with all-subset regressions from the principal components estimated from differently treated transmission spectra of the samples; the spectra were recorded on KBr pellets of sieved and unsieved unextracted wood powder and subjected to four different preprocessings and two different wavenumber selection schemes. The final model showed an adequate fit in the estimation data (R 2 = 0.74) as well as a good prediction performance in the test data (R 2 P = 0.90). This model was based on the wavenumber range of 1850-500 cm -1 of the linesubtraction-normalised spectra recorded from sieved samples. The model was used to predict lignin content in 64 samples of the same material. One of the clones had a slightly lower sapwood lignin content than the two other clones. The fertile growing site with fast growing trees showed slightly higher sapwood lignin content compared with the other two sites. The model was also used to predict the lignin content in the earlywood of 45 individual annual rings. Variation between individual stems and between annual rings was found to be large. No correlation was found between the lignin content and density of earlywood.

Variation in wood properties among five full-sib families of Norway spruce (Picea abies)

“…Lignin content was estimated by Fourier transform infrared (FTIR) spectroscopy [34]. Principal component regression (PCR) models were built for predicting the relative amount of lignin in wood analysed with the FTIR spectroscopy.…”

Linking molecular deadwood-inhabiting fungal diversity and community dynamics to ecosystem functions and processes in Central European forests

“…Klason lignin content was determined gravimetrically as the dry mass of solids remaining after sequential hydrolysis with sulfuric acid (72 % w/w); in a second step, acid soluble lignin was measured by UVphotometry in 4 % H 2 SO 4 (Effland 1977;Liers et al 2011). Total lignin was obtained by summing acid insoluble Klason lignin and acid soluble lignin (Raiskila et al 2007). The wood samples' pH values and contents of nutrient ions and ligninmodifying enzymes were measured in aqueous extracts.…”

Bagazo de sorgo dulce: una alternativa para la producción de etanol de segunda generación en Colombia (Parte I)

“…La no presencia del grupo carbonilo a 1600 cm -1 indica la ausencia de azúcares provenientes de la hemicelulosa en la muestra (Martínez, Jiménez, Ramírez, y Rojo, 2007). El hombro a 2900 cm -1 corresponde al grupo CH 2 guayacilosiringilo (Raiskila, 2007). La huella digital de cualquier espectro infrarrojo se analiza entre los 600 cm -1 y los 1800 cm -1 , los resultados obtenidos se compararon con los reportados por Rana, Langenfeld-Heyser, Finkeldey, y Polle (2010).…”

“…Los grupos hidroxilo característicos de la lignina, aparecen a 1338 cm -1 , es posible que este pico presente superposición entre los carboxilos propios de la lignina y el C=C de los aromáticos (Raiskila, 2007) . Los grupos aromáticos polisustituidos son característicos de 600 cm -1 .…”