Abstract

A new phenol-degrading marine fungal strain Fusarium oxysporum with high biodegradation activity and high tolerance of phenol was isolated from marine effluent of El-Max bay Alexandria, Egypt. Morphological, biochemical and 18S rRNA sequencing analysis identified the strain as F. oxysporum RA. This strain was capable of removing 12 and 8 mM of phenol and p-cresol in liquid minimal medium by 86 and 78% within 168 h, respectively. The fungus showed maximum activities of phenol hydroxylase (652 U/min/l at 8 mM of phenol) and aerobic p-cresol hydroxylase (377 U/min/l at 6 mM of p-cresol) at 72 h of incubation at 30°C. The Placket-Burman design was applied for medium optimization with respect to phenol degradation and phenol hydroxylase activity by F. oxysporum RA. The increase of KH₂PO₄ concentration and incubation temperature is significant (90%) for phenol degradation, while the increase of yeast concentration is significant (95%) for phenol hydroxylase activity production. These data demonstrated the prospect in protecting the environment from phenol and p-cresol pollution after the application of filamentous fungal strain of F. oxysporum RA.

Key words: Phenol and p-cresol biodegradation, marine Fusarium oxysporum RA, Placket Burman design, phenol and p-cresol hydroxylase assay