Gas chromatographic–mass spectrometric study of the degradation of phenolic compounds in wastewater olive oil by Azotobacter Chroococcum

Compounds present in wastewater olive oil (WWOO) which can be used in metabolic pathways of Azotobacter chroococcum (A. chroococcum) have been investigated. Some compounds such as syringic acid, p-coumaric acid and syringaldehyde do not favour microorganism growing up. However, it has been shown that in batch culture, polyphenolic compounds (PCs) such as protocatetic acid and p-hydroxybenzoic acid do facilitate the growing up of microorganism. What is more, the maximum concentration in which bacteria can grow was 0.3% (w/v) for both polyphenols. At higher concentrations, substrate inhibition was observed; which is characterized by decreasing growth rates. Therefore, A. chroococcum can grow up using PCs as an individual source of carbon and energy supply but it is also dependent on the type of the compound and on its concentration. A gas chromatography coupled mass spectrometry method has been used for the study of the degradation of simple phenolic compounds.