No abstract

Pharmaceuticals are widely used for treating human and animal diseases. Naproxen [(S) 6-methoxy-α-methyl-2-naphthalene acetic acid] and its sodium salt are members of the α-arylpropionic acid group of nonsteroidal anti-inflammatory drugs. Due to excessive usage of naproxen, this drug has been determined even in drinking water. In this study, four fungal strains Phanerochaete chrysosporium, Funalia trogii, Aspergillus niger, and Yarrowia lipolytica were investigated in terms of naproxen removal abilities. According to LC/MS data, A. niger was found the most efficient strain with 98% removal rate. Two main by-products of fungal transformation, O-desmethylnaproxen and 7-hydroxynaproxen, were identified by using LC/MS, 1HNMR, and 13CNMR. Our results showed that O-demethylation and hydroxylation of naproxen is catalyzed by cytochrome P450 enzyme system.

Yarrowia lipolytica NBRC 1658 could decolorize Reactive Black 5 effectively through biodegradation. The optimum conditions such as initial pH, glucose concentration, nitrogen concentration and initial dye concentration were determined. Correlations between decolorization and laccase and manganese peroxidase activities were investigated. Neither laccase nor manganese peroxidase (MnP) activities were determined in culture mediums. Y. lipolytica could decolorize 97% percentage of 50mg l-1 RB5 dye within 24 hours and could tolerate up to 300 mg l-1 of dye. It was found that decolorization occurred during the exponential growth phase. Aerobic batch conditions with 5g l-1 glucose and 1g l-1 ammonium sulphate at pH 7 were considered to be the optimum decolorizing conditions.

In this study, amino acid functionalized poly(2-hydroxyethyl methacrylate-N-methacrylolyl-l-phenylalanine) [PHEMAPA] cryogel discs were prepared. In this respect, phenylalanine containing N-methacryloyl-(L)-phenylalanine methyl ester (MAPA) was polymerized with 2-hydroxyethyl methacrylate (HEMA) without requirement of any activation step. Laccase bound poly(2-hydroxyethyl methacrylate-N-methacryloyl-l-phenylalanine) [Lac-PHEMAPA] cryogel discs were applied for decolorization of Reactive Blue-247 (RB-247). The ability of Lac-PHEMAPA cryogel discs on dye decolorization was found to be as 90% in 2 h and even more within 4h. The decolorization activities of 86% and 73% were observed at relatively low (4°C) and high (60°C) temperatures, respectively. The effect of dye concentration on dye decolorization and 100% decolorization activity was achieved in dye concentration between 50–300 ppm. Lac-PHEMAPA cryogel discs maintained 80% of its decolorization activity after six cycles. Consequently, the PHEMAPA cryogel discs are promising materials for immobilizing laccase. The Lac-PHEMAPA has a rapid dye decolorization in a broad range of temperature. The preparation is furthermore very stable and activity is preserved during storage.

Remazol Brilliant Blue R (RBBR) is a widely used carcinogenic and toxic dye. This study focused on RBBR dye from aqueous solution using potassium permanganate, cetyltrimethylammonium bromide (CTAB) modified, and unmodified Yarrowia lipolytica biomass as biosorbent. RBBR dye biosorption studies were carried out as a function of pH, initial dye concentration, biosorbent dose, contact time, and temperature. The pH of the aqueous solution strongly influenced the biosorption percent of RBBR dye. The highest dye biosorption capacity yield was obtained at pH 2-3 as well as above pH 3, very low yield biosorption of RBBR was observed. No differences were found between chemically modified and unmodified biomass in terms of RBBR dye biosorption capacity. In the first 15 min, almost 50% RBBR dye was removed from the solution and reached equilibrium within,180 min at pH 2. Biosorption isotherm obeyed Langmuir isotherm model and pseudo-secondorder kinetic model.