Evaluation of anatomical and physical properties of Khaya nthotheca (Welw.) C. DC. from forests of different altitudes in the democratic Republic of Congo

The anatomical and physical properties of Khaya anthotheca (Welw.) C. DC wood from the transition forest of middle altitude (zone 1) and the humid dense forest of low altitude (zone 2) in the East of the Democratic Republic of Congo were evaluated to ascertain the effect of growth area on the anatomical and physical properties. The heartwood vessels and rays number/mm2 varied significantly (P<0.001) between the two zones. The heartwood collected in zone 1 was significantly the richest (P<0.001) in vessel sand rays number. The average number of vessels and width of rays were higher in zone 2 and varied significantly (p < 0.0001) between the two zones.. Biotopes rays length was higher in zone 1 and varied significantly (p < 0.001) between the two zones. Nevertheless, the wood vessels distribution in the radial direction was homogeneous despite the zone; there was no significant difference in basic density, dry density and total volume shrinkage of K. anthotheca heartwood from the two zones..Keywords: Anatomy, vessel, rays, density, Khaya anthothec

Determination of hydroxyl groups in biorefinery resources via quantitative 31P NMR spectroscopy

The analysis of chemical structural characteristics of biorefinery product streams (such as lignin and tannin) has advanced substantially over the past decade, with traditional wet-chemical techniques being replaced or supplemented by NMR methodologies. Quantitative 31P NMR spectroscopy is a promising technique for the analysis of hydroxyl groups because of its unique characterization capability and broad potential applicability across the biorefinery research community. This protocol describes procedures for (i) the preparation/solubilization of lignin and tannin, (ii) the phosphitylation of their hydroxyl groups, (iii) NMR acquisition details, and (iv) the ensuing data analyses and means to precisely calculate the content of the different types of hydroxyl groups. Compared with traditional wet-chemical techniques, the technique of quantitative 31P NMR spectroscopy offers unique advantages in measuring hydroxyl groups in a single spectrum with high signal resolution. The method provides complete quantitative information about the hydroxyl groups with small amounts of sample (~30 mg) within a relatively short experimental time (~30-120 min)