Biorefinery of the Olive Tree—Production of Sugars from Enzymatic Hydrolysis of Olive Stone Pretreated by Alkaline Extrusion

Pablo Doménech, Aleta Duque, Isabel Higueras, Raquel Iglesias and Paloma Manzanares
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Pablo Doménech: Biofuels Unit, Energy Department—CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain
Aleta Duque: Biofuels Unit, Energy Department—CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain
Isabel Higueras: Biofuels Unit, Energy Department—CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain
Raquel Iglesias: Biofuels Unit, Energy Department—CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain
Paloma Manzanares: Biofuels Unit, Energy Department—CIEMAT, Avda. Complutense 40, 28040 Madrid, Spain

Energies, 2020, vol. 13, issue 17, 1-13

Abstract: This work addresses for the first time the study of olive stone (OS) biomass pretreatment by reactive extrusion technology using NaOH as the chemical agent. It is considered as a first step in the biological conversion process of the carbohydrates contained in the material into bio-based products. OS is a sub-product of the olive oil extraction process that could be used in a context of a multi-feedstock and multi-product biorefinery encompassing all residues generated around the olive oil production sector. OS biomass is pretreated in a twin-screw extruder at varying temperatures—100, 125 and 150 °C and NaOH/biomass ratios of 5% and 15% (dry weight basis), in order to estimate the effectiveness of the process to favour the release of sugars by enzymatic hydrolysis. The results show that alkaline extrusion is effective in increasing the sugar release from OS biomass compared to the raw material, being necessary to apply conditions of 15% NaOH/biomass ratio and 125 °C to attain the best carbohydrate conversion rates of 55.5% for cellulose and 57.7% for xylan in relation to the maximum theoretical achievable. Under these optimal conditions, 31.57 g of total sugars are obtained from 100 g of raw OS.

Keywords: lignocellulosic biomass; extrusion; pretreatment; olive oil industry; sub-product; fermentable sugars (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (3)

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