Trametes pubescens and Pleurotus ostreatus, immobilized on polyurethane foam cubes in bioreactors, were used to decolorize three industrial and model dyes at concentrations of 200, 1000 and 2000 ppm. Five sequential cycles were run for each dye and fungus. The activity of laccase, Mn-dependent and independent peroxidases, lignin peroxidase, and aryl-alcohol oxidase were daily monitored during the cycles and the toxicity of media containing 1000 and 2000 ppm of each dye was assessed by the Lemna minor (duckweed) ecotoxicity test. Both fungi were able to efficiently decolorize all dyes even at the highest concentration, and the duckweed test showed a significant reduction (p < or = 0.05) of the toxicity after the decolorization treatment. T. pubescens enzyme activities varied greatly and no clear correlation between decolorization and enzyme activity was observed, while P. ostreatus showed constantly a high laccase activity during decolorization cycles. T. pubescens showed better decolorization and detoxication capability (compared to the better known P. ostreatus). As wide differences in enzyme activity of the individual strains were observed, the strong decolorization obtained with the two fungi suggested that different dye decolorization mechanisms might be involved.

• MeSH
• Coloring Agents metabolism   MeSH
• Biodegradation, Environmental MeSH
• Bioreactors microbiology   MeSH
• Fermentation MeSH
• Cells, Immobilized metabolism   MeSH
• Pleurotus enzymology   metabolism   MeSH
• Polyporales enzymology   metabolism   MeSH
• Industrial Microbiology * MeSH
• Industrial Waste * MeSH
• Textile Industry * MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Coloring Agents MeSH
• Industrial Waste * MeSH

Dye decolorization capacity of two white-rot fungi, Irpex lacteus and Phanerochaete chrysosporium, was compared in N-limited liquid cultures. The agitated cultures showed lower ability to decolorize azo dyes Reactive Orange 16 and Naphthol Blue Black than static cultures. Similar effect was also observed with other structurally different synthetic dyes. The effect of surfactants on the decolorization process is discussed. A significant increase in the Reactive Orange 16 decolorization by the agitated I. lacteus cultures was observed after adding 0.1% Tween 80, following a higher Mn-dependent peroxidase production. The in vitro dye decolorization using the purified enzyme proved its decolorization ability.

• MeSH
• Azo Compounds metabolism   MeSH
• Coloring Agents metabolism   MeSH
• Basidiomycota drug effects   enzymology   metabolism   MeSH
• Enzyme Induction MeSH
• Peroxidases metabolism   MeSH
• Phanerochaete enzymology   metabolism   MeSH
• Polysorbates pharmacology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Azo Compounds MeSH
• Coloring Agents MeSH
• manganese peroxidase MeSH Browser
• Peroxidases MeSH
• Polysorbates MeSH
• reactive orange 16 MeSH Browser

Three isolates of Pseudomonas aeruginosa were used for seed treatment of rice; all showed plant growth promoting activity and induced systemic resistance in rice against Rhizoctonia solani G5 and increased seed yield. Production of salicylic acid (Sal) by P. aeruginosa both in vitro and in vivo was quantified with high performance liquid chromatography. All three isolates produced more Sal in King's B broth than in induced roots. Using a split root system, more Sal accumulated in root tissues of bacterized site than in distant roots on the opposite site of the root system after 1 d, but this difference decreased after 3 d. Sal concentration 0-200 g/L showed no inhibition of mycelial growth of R. solani in vitro, while at > or =300 g/L it inhibited it. P. aeruginosa-pretreated rice plants challenged inoculation with R. solani (as pathogen), an additional increase in the accumulation of peroxidase was observed. Three pathogenesis-related peroxidases in induced rice plants were detected; molar mass of these purified peroxidases was 28, 36 and 47 kDa. Purified peroxidase showed antifungal activity against phytopathogenic fungi R. solani, Pyricularia oryzae and Helminthosporium oryzae.

• MeSH
• Antibiosis physiology   MeSH
• Antifungal Agents metabolism   MeSH
• Pest Control, Biological methods   MeSH
• Plant Roots growth & development   metabolism   MeSH
• Salicylic Acid metabolism   MeSH
• Plant Diseases microbiology   MeSH
• Peroxidases metabolism   MeSH
• Immunity, Innate MeSH
• Pseudomonas aeruginosa physiology   MeSH
• Rhizoctonia pathogenicity   MeSH
• Oryza enzymology   microbiology   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Antifungal Agents MeSH
• Salicylic Acid MeSH
• Peroxidases MeSH

The extracellular enzyme activity and changes in soil bacterial community during the growth of the ligninolytic fungus Pleurotus ostreatus were determined in nonsterile soil with low and high available carbon content. In soil with P. ostreatus, the activity of ligninolytic enzymes laccase and Mn-peroxidase was several orders of magnitude higher than in soil without the fungus. Addition of lignocellulose to soil increased the activity of cellulolytic fungi and the production of Mn-peroxidase by P. ostreatus. The counts of heterotrophic bacteria were more significantly affected by the presence of lignocellulose than by P. ostreatus. The effects of both substrate addition and time (succession) were more significant factors affecting the soil bacterial community than the presence of P. ostreatus. Bacterial community structure was affected by fungal colonization in low carbon soil, where a decrease of diversity and changes in substrate utilization profiles were detected.

• MeSH
• Bacteria growth & development   MeSH
• Cellulose metabolism   MeSH
• Fungal Proteins biosynthesis   MeSH
• Laccase biosynthesis   MeSH
• Lignin metabolism   MeSH
• Peroxidases biosynthesis   MeSH
• Pleurotus enzymology   growth & development   MeSH
• Soil MeSH
• Soil Microbiology * MeSH
• Carbon metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Cellulose MeSH
• Fungal Proteins MeSH
• Laccase MeSH
• Lignin MeSH
• lignocellulose MeSH Browser
• manganese peroxidase MeSH Browser
• Peroxidases MeSH
• Soil MeSH
• Carbon MeSH