Bioenergetic strategy of microalgae for the biodegradation of tyrosol and hydroxytyrosol.
Olive mill wastewater has significant polluting properties due to its high phenolic content [mainly tyrosol (trs) and hydroxytyrosol (htrs)]. Growth kinetics and a series of fluorescence induction measurements for Scenedesmus obliquus cultures showed that microalgae can be tolerant of these phenolic compounds. Changes in the cellular energy reserves and concentration of the phenolic compounds adjust the "toxicity" of these compounds to the microalgae and are, therefore, the main parameters that affect biodegradation. Autotrophic growth conditions of microalgae and high concentrations of trs or htrs induce higher biodegradation compared with mixotrophic conditions and lower phenolic concentrations. When microalgae face trs and htrs simultaneously, biodegradation begins from htrs, the more energetically demanding compound. All these lead to the conviction that microalgae have a "rational" management of cellular energy balance. Low toxicity levels lead to higher growth and lower biodegradation, whereas higher toxicity levels lead to lower growth and higher biodegradation. The selection of appropriate conditions (compatible to the bioenergetic strategies of microalgae) seems to be the key for a successful biodegradation of a series of toxic compounds, thus paving the way for future biotechnological applications for solving complicated pollution problems, like the detoxification of olive mill wastewater.
Department of Biology, University of Crete, Voutes University Campus, GR-70013 Heraklion, Greece.|Laboratory of Plant Biotechnology and Genomic Resources, Institute for Olive Tree, Subtropical Plants and Viticulture, Hellenic Agricultural Organization DEMETER, GR-71003, Heraklion, Greece.
Aikaterini
A
Papazi
Department of Biology, University of Crete, Voutes University Campus, GR-70013 Heraklion, Greece.
Andreas
A
Ioannou
Department of Biology, University of Crete, Voutes University Campus, GR-70013 Heraklion, Greece.
Myrto
M
Symeonidi
Laboratory of Plant Biotechnology and Genomic Resources, Institute for Olive Tree, Subtropical Plants and Viticulture, Hellenic Agricultural Organization DEMETER, GR-71003, Heraklion, Greece.
Andreas G
AG
Doulis
Department of Biology, University of Crete, Voutes University Campus, GR-70013 Heraklion, Crete, Greece, Tel.: +30-2810-394059, Fax: +30-2810-394408.
Kiriakos
K
Kotzabasis
D052818:Autotrophic Processes; D001673:Biodegradation, Environmental; D004734:Energy Metabolism; D007220:Industrial Waste / Q000032:analysis*; D058086:Microalgae / Q000254:growth & development / Q000378:metabolism*; D031658:Olea; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000378:metabolism; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000378:metabolism*; D018508:Water Purification / Q000379:methods*
D007220:Industrial Waste; D010626:Phenylethyl Alcohol; D062065:Wastewater; D014874:Water Pollutants, Chemical; C005975:3,4-dihydroxyphenylethanol; C011867:4-hydroxyphenylethanol
biodegradation; hydroxytyrosol; olive mill wastewater; photosynthesis; tyrosol