Production of bioethanol during the bioremediation of olive mill wastewater at high temperatures

Abstract

Olive mill wastewater (OMW) also called olive black mill, released in large quantities in the environment in countries producing olive oil, is difficult to degrade because of it is rich in phenols and polyphenols. Recently, many reports show that its bioremediation could be achieved while producing valuable products such as medicinal mushrooms, as well as bioactive polyphenolic compounds with antimicrobial, antioxidant, or anti-inflammatory activities. We demonstrate here the feasibility of producing bioethanol during a bioremediation process that significantly reduces the polluting charge of OMW by aerobic yeast fermentation. Indeed, we show the production of bioethanol as a coproduct of the bio-treatment of olive mill wastewater with selected yeast strains from the following species: Candida tropicalis, Pichia kudriavzevii, Pichia manshurica, Kluyveromyces marxianus and Ogataea zsoltii, which are able to produce ethanol at high temperatures (≥42 °C) and therefore adapted to fermentation in hot climate conditions.