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Diclofenac (DCF) is a non-steroidal anti-inflammatory drug and, as pollutant, it represents a persistent residue hazard to health and to the environment. Trametes versicolor was previously selected for its ability in diclofenac biodegradation (up to 20%) during cultivation in submerged system under aerobic conditions at an initial DCF concentration of 10 mg L-1. The influence of some factors such as nitrogen sources glucose, MnSO4•H2O, CuSO4•5H2O, inoculum level, initial DCF concentration and incubation time, upon the biodegradation potential was examined by Plackett-Burman analysis. The parameters significantly influencing the DCF biotransformation were found to be yeast extract, glucose, CuSO4•5H2O and inoculum level. In these optimum conditions, the DCF biotransformation yield was 80%. This result was 60% superior in comparison with the medium without optimization. Analysis of variance exhibited a high coefficient of determination (R²) value of 0.9987 and ensured that the polynomial model with the experimental data was a satisfactory one. Optimal conditions obtained in this work led to a solid foundation for further use of Trametes versicolor in biotreatment of high strength DCF pollutant effluents in water wastes. [ABSTRACT FROM AUTHOR]

Thirty wild new strains of filamentous bacteria belonging to the genus Streptomyces isolated from different Romanian soil samples and ten strains from Collection of microorganisms of Bioaliment Research Platform (acronym MIUG) were tested and screened for their ability to produce extracellular tyrosinase and laccase. Based on preliminary qualitative screening assays for the extracellular phenoloxidases production carried out by stationary cultivation on Gause agar medium (GMA) supplemented with 1% (w/w) L-tyrosine, nineteen strains were selected as active producers. Furthermore, a quantitative selection based on active strains ability to produce tyrosinase and laccase by submerged cultivation in liquid Gause salts basal medium supplemented with 1 g L-1 L-tyrosine and 0.001 g L-1 CuSO4, during 168 hours was performed. Results showed that 70% of the Streptomyces strains have a good potential for producing tyrosinase and 30% of strains were remarked for their ability to produce laccase. Moreover, it was observed that, Streptomyces strains coded MIUG 4.89 and MIUG 4.88 from MIUG Collection have the ability to simultaneously produce both enzymes. The effect of temperature and pH on enzymes activity was also investigated. The optimum temperature for both activity (tyrosinase and laccase) was found to be 30°C. Laccase was found active over a pH range of 4.0 to 6.0 with maximum activity at pH 5.0. The optimum pH for tyrosinases activity was observed to be around 7.0. The obtained results are important for future applications of Streptomyces phenoloxidases in different areas. [ABSTRACT FROM AUTHOR]