The addition effect of Pseudomonas aeruginosa on biodegradation of methyl orange dye by brown-rot fungus Fomitopsis pinicola

The addition effect of Pseudomonas aeruginosa on methyl orange (MO) biodecolorization by Fomitopsis pinicola had been investigated. P. aeruginosa was added into F. pinicola culture at 2, 4, 6, 8, 10 mL (1 mL 5.05 χ 1012 CFU). The addition of 4 ml of P. aeruginosa showed the highest MO biodecolorization approximately 99.53%, while by F. pinicola only was 77.22% in potato dextrose broth (PDB) medium for 7 days incubation. Four metabolites were detected from MO degradation by mixed cultures such as 4-(4-(dimethylimino) hydroxy-cyclohexa-2,5-dien-1-ylidene) hydrazinyl) phenolate; 4-(hydroxy-4-iminio-cyclohexa-2,5-dien-1-ylidene) hydrazinyl) benzene sulfonate; 4-(4-(dimethylimino) methoxy-cyclohexa-2,5-dien-1-ylidene) hydrazinyl) hydroxy-benzene sulfonate; and 4-(hydroxy-4-iminio-cyclohexa-2,5-dien-1-ylidene) hydrazinil) hidroxy-benzene sulfonate. The mixed cultures transformed MO via three pathways: (1) desulfonylation, (2) demethylation, and (3) hydroxylation. These results indicated that P. aeruginosa can enhance MO biodecolorization by F. pinicola.