Title:
D-Xylose Production from Endocarp of Olive Fruit: Optimization of Dilute Sulphuric-Acid Hydrolysis
Author(s):
Cuevas, M., Sánchez, S., García, J.F., Olivencia, J., Saleh, M.
Document(s):
Paper
Abstract:
Endocarps in fragments from olive fruits (EF) have a high content of xylans and could be a potential material for production to D¬xylose by hydrolysis with inorganic acids. Hydrolysis of EF by diluted sulphuric acid at high temperature was researched in this study. Firstly, the effects of two operational conditions, including reaction temperature (180–220ºC) and time (2–8 min), on monosaccharides yields were examined using a 22 factorial design. An acid concentration of 0.01 M and a solid/liquid ratio of 1/6 were set. D¬xylose was the major sugar in the hydrolysates, with a maximum yield above 0.20 kg kg–1EF that was achieved at 201ºC reaction temperature for 5.2 min. Under those conditions the low content of L¬arabinose, D-galactose, and D¬glucose (< 0.01 kg monosaccharide –1 –1–1 kgEF), and of the fermentation inhibitors (< 0.001 kg HMF kgEF; < 0.033 kg acetic acid kgEF) provided an interesting subtract for its biochemical conversion to xylitol or ethanol. Finally, a new factorial design was developed, with the optimal condition derived from the first experimental series, to study the effect of acid concentration (0.01–0.03 M) and solids loading (50–150 g) on sugars production. Although the maximum D¬xylose yield decreased with the increase of solid/liquid ratio, the conditions that release more pentoses at high solids loading were determined. Thus, it was possible to obtain direct hydrolysates with D¬xylose concentrations close to 85 g dm–3. This research demonstrates that the response surface methodology (RSM) can be employed for optimising the D¬xylose production by acid hydrolysis of olive stone, and that the raw material is a rich source of pentoses.
Keywords:
D-xylose, olive stone, dilute sulphuric-acid hydrolysis, response surface methodology
Topic:
R&D on Processes for Solid, Liquid and Gaseous Fuels from Biomass
Subtopic:
Bioethanol production and sugar release from lignocellulosic
Event:
20th European Biomass Conference and Exhibition
Session:
3DV.1.57
Pages:
1692 - 1696
ISBN:
978-88-89407-54-7
Paper DOI:
10.5071/20thEUBCE2012-3DV.1.57
Price:
FREE
