Screening Rhizosphere Fungi for the Production of Phenoloxidising Enzymes.

SCREENING RHIZOSPHERE FUNGI FOR THE PRODUCTION OF PHENOLOXIDIZING ENZYMES.

 El-Sayed M. El-Morsy

Botany Department, Damietta Faculty of Science, Mansoura University, New Damietta, PO. BOX  34517 (30). Damietta Province, Egypt. e-mail@mum.mans.eun.eg

Abstract

Sixty-three species from the ecto- and endorhizosphere were examined for production of phenolases and their potentiality in lignin biodegradation by agar spot tests. These fungi exhibited marked growth on “tannin” containing media, but only few oxidize it. All isolates showed positive reaction for general oxidases and peroxidases. Most species are tyrosinase positive, and few are laccase positive. The production of laccase and tyrosinase varied with the used media. Among the laccase positive species, the reaction also varied according to the kind of phenolic substrate used whether 1-naphthol or syringaldazine and only seven species reacted with both of them. Percentage of laccase producing species was higher in endo- than ectorhizosphere species whereas, tyrosinase-producing species were approximately equal. Of the tested species, Papulaspora immersa showed profound tyrosinase reaction, whereas Agonomycetes sp.4 exhibited intense laccase reaction, and Chaetomium globosum and Aspergillus aureolatus gave high peroxidase activity. Participation of these fungi and their enzymes in lignin biodegradation was suggested.

Key words:endophytes, lignin biodegradation, soil fungi.