Sunday, April 29, 2007

Biomass and chemical production using Tagasaste and Leucaena species

M.M. García, Fariñas S., Caparros S., Yáñez R., and López F. Department of Chemical Engineering, Universidad de Huelva, Avda. Fuerzas Armadas, s/n, Huelva, 21071, Spain

Soil degradation has been described as an important problem in Europe. The possible bioremediation solutions involve an agricultural sustainability to enhance progressively the productive capacity without jeopardizing future potential. Leguminous species or the ones vaccinated against bacteria have been proposed from the Bradyrhizobium, Rhizobium, Sinorhizobium and Mesorhizobium genera, helping to the recovery of already degraded grounds. Woody legumes can prevent erosion, increase soil fertility and facilitate the growth of other plant species.
   In order to identify non-woody species usable for biomass, fuels and chemicals (paper) production, three Leucaena species and Tagasaste (chamaecitysus proliferus) were tested. All the Leucaena (Leucocephala, Diversifolia and Colinsii) species and tagasaste showed a good soil and climatic adaptation to Spain Southwest. Studied species showed biomass productivity ranges from 67.14 to 9.44 t ha−1 and 3.7 to 42.2 t ha-1 (o.d.b.) under Mediterranean conditions for one year leucaena and tagasaste sprouts respectively. Relatively lower lignin content in Leucaena (from 15.7% to 21.4%) species and tagasaste (16.7%) has been found with respect to other vegetal species. The α-cellulose contents (39.4% to 45.3% and 45.7 for tagasaste) are in the range of the normal values expected for the other non-wood raw.
The study confirms the feasibility of organocell yield pulping and totally chlorine free bleaching process to Leucaena species and tagasaste. Organocell process provides an efficient delignification (kappa index 12.4 and pulp yield 42.2%) for L.leucocephala  and suitabily physical characteristics of paper sheet after peroxide bleaching process (tensile index 19.7 kNm/kg for Leucaena diversifolia and brightness 70.9% ISO for tagasaste).