Open AccessIncrease in Fermentable Sugars of Olive Tree Pruning Biomass for Bioethanol Production: Application of an Experimental Design for Optimization of Alkaline Pretreatment
Author(s) -
Arminda Mamaní,
Yolanda Paola Maturano,
Laura Herrero,
Laura Montoro,
Fabiana Sardella
Publication year - 2022
Publication title -
periodica polytechnica. chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.322
H-Index - 19
eISSN - 1587-3765
pISSN - 0324-5853
DOI - 10.3311/ppch.18247
Subject(s) - hemicellulose , chemistry , pulp and paper industry , cellulose , biofuel , raw material , hydrolysis , sodium hydroxide , biomass (ecology) , enzymatic hydrolysis , bagasse , sugar , calcium hydroxide , factorial experiment , lime , starch , food science , waste management , biochemistry , mathematics , agronomy , materials science , organic chemistry , engineering , biology , statistics , metallurgy
Olive Tree Pruning (OTP) biomass can be considered a suitable source of fermentable sugars for the production of second-generation bioethanol. The present study proposes a remarkable alternative for the valorization of olive tree pruning residues. OTP biomass was processed using a sequential calcium hydroxide pretreatment/enzymatic hydrolysis. A 24–1 half fractional factorial design was adopted for the screening of process variables and a central composite design was used for the optimization stage. Temperature and lime loading resulted statistically significant. The following optimal conditions were obtained: 0.01 g of Ca(OH)2/g of dry material, 20 g of H2O/g of dry material at 160 °C for 2 h. The mathematical model that governs this alkaline pretreatment was obtained with a 76% adjusted determination coefficient, which means that it is a good representation of the process. Under optimal operating conditions, 13% of the cellulose and 88% of the hemicellulose was solubilized. Moreover, the fermentable sugar content increased 1800% compared with the initial conditions, obtaining 240 g of glucose per kg of OTP residue. The fermentable sugars obtained after the calcium hydroxide pretreatment and enzymatic hydrolysis of OTP biomass yielded 2.8 g of ethanol/100 g of raw material.