BIOCHEMICAL CONVERSION OF TUNISIAN LIF OF DATE PALM PHOENIX DACTYLIFERA L. TO BIOETHANOL PRODUCTION

摘要

The date palm is one of the oldest crops grown especially in arid and semi-arid bioclimatic zones of thernArabian Peninsula, North Africa and in the Middle East. The number of date palms in the world has been estimatedrnby 100000 million trees; with 2 603 500 date palm trees in an area of 22 680 ha in Tunisia tree. The global palm daternwaste production is approximately 2 million t/year. The lif is the by-product of the palm date tree.Thus, it could bernconsidered as an available lignocellulose feedstock. For this reason, the aim of this work was to produce bioethanolrn2G as renewable source of energy from both young and old lif of date palm, Phoenix dactylifera L. Therefore, tornreach this purpose, the first step was to optimize the thermochemical pretreatment while studying the effect of the twornmain factors: temperature and acid concentration, in order to have the maximum yield of D-glucose. The second steprnwas to explore enzymatic hydrolysis, and the last one was the fermentation process. This research proves that thernmost adequate conditions for pretreatment of both wastes date palm are 220°C in hydrothermal conditions (H_2SO_4 atrn0 M). Indeed, these operating conditions allow to obtain reducing sugars concentrations about 2.39±1.09 g/dm~3 forrnyoung lif and 1.98±0.12g/dm~3 for old lif, and D-glucose concentrations about 0.11± 0.13g/dm~3 for young fibers andrn0.093±0.016 g/dm~3 for old fibers. After enzymatic hydrolysis, the hydrolysates containing D-glucose were fermentedrnby Pachysolen tannophilus to ethanol, reaching 3.24±0.81 g/dm~3 for young lif and 4.55±1.04 g/dm~3 for old lif,rnrespectively.