Detoxification of olive mill wastewaters by Moroccan yeast isolates

• Published in: Biodegradation (Dordrecht) 2008-06, Vol.19 (3), p.337-346
• Main Authors: Ben Sassi, A, Ouazzani, N, Walker, G. M, Ibnsouda, S, El Mzibri, M, Boussaid, A
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Bioassays; Biodegradation; Biodegradation of pollutants; Biological and medical sciences; Biomedical and Life Sciences; Biotechnology; Candida; Carbohydrate assimilation; Chemical oxygen demand; COD; Detoxification; Environment and pollution; Food industries wastewaters; Fundamental and applied biological sciences. Psychology; Geochemistry; Germination - drug effects; Germination assays; Hordeum - drug effects; Hordeum - growth & development; Industrial applications and implications. Economical aspects; Industrial Waste; Industrial wastewater; Life Sciences; Microbiology; Morocco; Olive Oil; Olive oil mill wastewaters; Organic nitrogen; Original Paper; Phenols; Phytotoxicity; Plant Oils - isolation & purification; Pollutant removal; Principal components analysis; Seed germination; Seeds - drug effects; Seeds - growth & development; Soil Science & Conservation; Terrestrial Pollution; Total phenols; Toxicology; Waste Disposal, Fluid; Waste Management/Waste Technology; Waste Water Technology; Water Management; Water Pollutants - metabolism; Water Pollutants - toxicity; Water Pollution Control; Water treatment; Yeast; Yeasts; Yeasts - metabolism
• ISSN: 0923-9820; 1572-9729
• DOI: 10.1007/s10532-007-9140-8

A total of 105 yeast strains were isolated from Moroccan olive oil production plants and evaluated for their ability to grow in olive oil mill wastewaters (OMW). The 9 isolates that grew best on OMW were selected for further study to evaluate their effect on removal of organic pollutants and OMW phytotoxicity (barley seed germination test). The results showed that at least four yeast isolates effectively lowered the toxicity of this effluent in addition to providing very useful materials in terms of both yeast biomass (6 g/l DW) and an irrigation fluid. This group of yeast isolates significantly reduced the concentration of total phenols (44% removal) and Chemical Oxygen Demand, COD (63% removal). The best germination rate of 80% for undiluted OMW was obtained for strain Candida holstii that also increased the pH from 4.76 to 6.75. Principal component analysis of the results obtained for the best yeast strains confirmed the importance of COD and total phenol reduction along with increase of organic nitrogen and final pH for the improvement of germination rates and phytotoxic reduction. This study has highlighted the potential of indigenous yeasts in detoxification of olive mill wastewaters.