Tanyol, Mehtap; Uslu, Gulsad

Lipases are industrially important enzymes produced by a great variety of microorganisms. In this study, the production of extracellular lipase by Pseudomonas fluorescens (NRLL B-2641) using submerged fermentation was studied: The effects of. initial pH, carbon source, nitrogen source and metal ion addition on lipase activity were investigated using batch experiments. The highest enzyme activity and biomass production obtained were 2.50 U mL(-1) and 2.95 g cell dry wt. L-1, respectively, using a fermentation medium with 1% corn oil as the carbon source, 0.4% peptone as the nitrogen source and an initial pH of 6.0. The addition of calcium increased the enzyme activity to 3.30 U mL(-1). Thus, initial lipase activity, which was 0.92 U mL(-1), increased 356%. Partial characterization of crude lipase was performed to determine the optimum pH and temperature. The crude lipase displayed high activities at pH 6.0-8.5 and 35-65 degrees C, with maximum activity at pH 8.0 and 50 degrees C.

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Demir, Veysel; Yildirim, Numan; Yildirim, Nuran Cikcikoglu; Ergin, Sezai; Cumurcu, Aysenur

The aim of this study was to evaluate the bacteriological contamination of drinking water in Tunceli, Turkey. For this purpose, the presence of total coliforms, Escherichia coli, and Enterococci was investigated at ten water sampling stations in the Tunceli province. The microbiological dataset of the ten stations were obtained from the Health Directorate of Tunceli for this study. Detection of E. coli and total coliform was performed using the membrane filtration method, Turkish Standards (TS) 9308- 1.(1) Enterococci were enumerated according to the TS 7899-2(2) method. Varying levels of bacterial contamination were recorded in samples from these ten stations. It was observed that bacterial contamination was highest in the village of Burmagecit. Results indicate that microbiological contaminations were found to be above the allowable amount for drinking waters given by the World Health Organization (WHO). Because of this, appropriate disinfection methods and regular quality control mechanisms must be implemented by the Health Directorate of Tunceli.

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