Potential of agroindustrial waste from olive oil industry for fuel ethanol production.
Olive pulp (OP) is a highly polluting semi-solid residue generated from the two-stage extraction processing of olives and is a major environmental issue in Southern Europe, where 80% of the world olive oil is produced. At present, OP is either discarded to the environment or combusted with low calorific value. In this work, utilization of OP as a potential substrate for production of bioethanol was studied. Enzymatic hydrolysis and subsequent glucose fermentation by baker's yeast were evaluated for OP from 10% to 30% dry matter (i.e., undiluted). Enzymatic hydrolysis resulted in an increase in glucose concentration by 75%, giving final glucose yields near 70%. Fermentation of undiluted OP hydrolysate (OPH) resulted in the maximum ethanol produced (11.2 g/L) with productivity of 2.1 g/L/h. Ethanol yields were similar for all tested OPH concentrations and were in the range of 0.49-0.51 g/g. Results showed that yeast could effectively ferment OPH even without nutrient addition, revealing the tolerance of yeast to OP toxicity. Because of low xylan (12.4%) and glucan (16%) content in OP, this specific type of OP is not a suitable material for producing only ethanol and thus, bioethanol production should be integrated with production of other value-added products.
Georgieva
Tania I
TI
Fluxome Scienes A/S, DK-2800 Lyngby, Denmark.
Ahring
Birgitte K
BK
D018407:Bacterial Physiological Phenomena; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology*; D003198:Computer Simulation; D003247:Conservation of Natural Resources; D004736:Energy-Generating Resources; D000431:Ethanol / Q000378:metabolism*; D005240:Feasibility Studies; D019649:Food Industry / Q000639:trends*; D007220:Industrial Waste / Q000517:prevention & control*; D008954:Models, Biological; D000069463:Olive Oil; D010938:Plant Oils / Q000378:metabolism*
D007220:Industrial Waste; D000069463:Olive Oil; D010938:Plant Oils; D000431:Ethanol