Anatomical and chemical composition of <I>Detarium Senegalense</I> J.F. Gmel Bark

Abstract

The anatomical and chemical composition of Detarium senegalense bark was studied after grinding and fractioning into different particles sizes. The bark of D. senegalense mature trees was fractionized into fine and coarse granulometric particles using 0.150 mm and 4.0 mm mesh respectively. The bark showed the following compositions for fine and coarse bark granulometric respectively as ash (10.9 % and 12.1 %), total extractives (20.9 % and 16.4 %), suberin (0.97 % and 0.94 %) and lignin (36.5 % and 31.2 %). Ash elemental composition was different in both fractionized biomass. The suberin content in both fractions were as well low. Fine D. senegalense bark contained more extractives in relation to coarse granulometric D. senegalense bark. For the elemental compositional characterization, the values obtained for the fine and coarse bark solutes were almost in the same range for N (0.75 % and 0.72 %), P (0.095 % and 0.092
%), Mg (0.13 % and 0.14 %), Ca (6.6 % and 6.2 %), K (0.33 % and 0.31 %), Ni (1.81 mg/kg and 1.77 mg/kg ), Cr (1.98 mg/kg and 1.93 mg/kg), Pb (2.02 mg/kg and 2.05 mg/kg). However, high concentration of Zn was found in fine granules of D. sengalense bark that is, 29 mg/kg compared to 13 mg/kg in the  coarse bark. Extractives were present preferentially in the finest fraction in dichloromethane, ethanol and water soluble. D. senegalense bark had a high content of 36.5 and 31.2 cellulose and hemicelluloses especially in the coarser fraction. The rich lignin content of 39.5 and 20.9 in D. senegalense wood makes it a good potential resource for adhesives, chemical and biorefinery industries. The significant content of extractive in D. senegalense suggests conferment of natural durability to the wood. Particle size reduction by grinding is a unit operations that may be used as selective enrich solutes in soluble materials.

Keywords: Anatomical structure, Chemical composition, Detarium senegalense, fine granulometric fraction, coarse granulometric fraction