Candida tropicalis ile sulu çözeltilerden metal-kompleks boyar madde giderimi : üreme ve inhibisyon kinetiği

Abstract

Bioaccumulation of dye with C. tropicalis  Growth and Inhibition Kinetics of C. tropicalis  Effect of pH and sugar concentration on growth and dye bioaccumulation of C. tropicalis Figure A. The removal of metal-complex dye with Candida tropicalis Purpose: In the present study, we investigated the bioaccumulation of C.I. Acid Violet 90 1:2 metal complex dye (AV90) with Candida tropicalis in a batch system. Molasses was chosen as a source of carbon for the yeast The effects of pH, the dye concentration and the total sugar concentration on dye bioaccumulation and yeast growth were analyzed. In order to describe the inhibitory effect of AV90 dye on growth and bioaccumulation properties, the linear mixed-type inhibition kinetic model was used. Theory and Methods: During dying process, nearly 10-15% of the dyes and other chemicals are released into the environment. Physical, chemical, and biological treatment processes are involved in dye wastewater treatment. For bioremediation of dyes, several studies have focused on a wide variety of microorganisms which are capable of decolorizing a wide range of dyes. Yeasts, which is a low-cost and convenient source of microorganisms, have long been known to be capable of bioaccumulation of dyes under a wide range of external conditions. Dye bioaccumulation experiments with C. tropicalis were carried out in a 250 mL volumetric flask at a working volume of 150 mL at 30 °C in a shaking bath for 15 days (140 rpm) with dye adapted yeast. Results: The effect of pH on bioaccumulation was investigated at different initial pH values (3-6). The maximum specific growth rate of C. tropicalis and bioaccumulation percent of dye were obtained as 0.22 1/h and 50.3% at pH 5. Dye bioaccumulation and specific growth rates were found to be strongly depend on both initial total sugar and AV90 concentration. Monod equation was used to determine the relationship between growth and substrate (reducing sugar concentration) in the bioaccumulation of AV90 with C. tropicalis. It is observed that the inhibition of AV90 dye is a mixed type inhibition which is defined as a mixture of partial competitive and non-competitive inhibition. The Monod saturation constant (KS, g/L) and maximum specific growth rate (m, 1/h) of control medium without dye were obtained as 1.21 g/L and 0.267 1/h for C. tropicalis. The maximum growth rate mI decreased from 0.267 to 0.227 1/h while the K I S Monod saturation constant values increased from 1.21 to 1.68 g/L (K I S) for the increasing AV90 concentration from 0 to 400 mg/L. The inhibition constant, KI was obtained as 1008 mg/L from lineer mixed type equation. Conclusion: In this study, the removal of metal-complex azo dye (AV90) from aqueous solutions was investigated by using C. tropicalis. In the process of AV90 removal, the effect of pH, initial dye concentration and reducing sugar concentration on yeast growth and dye bioaccumulation were investigated, and it was observed that these parameters affect both yeast growth and the bioaccumulation of dyes. As a result, the e...