Gülşad Uslu

Bioaccumulation of copper(II), lead(II) and chromium(VI) by growing Aspergillus niger

Abstract The effect of copper(II), lead(II) and chromium(VI) ions on the growth and bioaccumulation properties of Aspergillus niger was investigated as a function of initial pH and initial metal ion concentration. The optimum pH values for growth and metal ion accumulation were determined as 5.0, 4.5 and 3.5 for copper(II), lead(II) and chromium(VI) ions, respectively. Although all metal ion concentrations caused an inhibition effect on the growth of A. niger , it was capable of removing of copper(II) and lead(II) with a maximum specific uptake capacity of 15.6 and 34.4 mg g −1 at 100 mg dm −3 initial copper(II) and lead(II) concentration, respectively. Growth of A. niger was highly effected by chromium(VI) ions and inhibited by 75 mg dm −3 initial chromium(VI) concentration since some inhibition occurred at lower concentrations.

The effect of Cd (II), Pb (II) and Cu (II) ions on the growth and bioaccumulation properties of Rhizopus arrhizus

Abstract The comparative growth and Cd (II), Pb (II) and Cu (II) ions bioaccumulation properties of Rhizopus arrhizus were investigated as a function of initial pH, temperature and initial metal ion concentrations. The optimum initial pH for Cd (II), Pb (II) and Cu (II) were determined as 3.5, 4.0 and 4.5 at optimum temperatures for each metal ion, respectively. Results indicated that microbial growth and metal ion uptake of R. arrhizus were significantly affected by initial metal ion concentrations. High microbial growth and Cd (II), Pb (II) and Cu (II) accumulation yields were found at low initial metal ion concentrations. R. arrhizus was more efficient in accumulating larger amounts of Cd (II) and Pb (II) ions than that of Cu (II) ions.

Efficacy of Pulsed UV-Light Treatment on Wastewater Effluent Disinfection and Suspended Solid Reduction

AbstractDisinfection of municipal wastewater effluents is a critical component of water pollution control. To achieve this, novel alternative disinfection technologies have been getting attention recently such as pulsed ultraviolet (UV) light, which can be used to inactivate microorganisms in a short time. Therefore, the research reported in this paper was undertaken to determine the efficacy of pulsed UV light for inactivation of Escherichia coli and Bacillus subtilis spores, in synthetic and real municipal wastewater effluent. The results with synthetic municipal wastewater effluent demonstrated that complete inactivation was obtained with an 8-cm sample distance, 30-mL sample volume, and 15-s time combination for E. coli [8.53log10 colony-forming units (CFUs)/mL reduction], whereas a 15-mL sample volume (with the same sample distance and treatment time) was required for B. subtilis (7.57log10CFU/mL reduction) at total energy dose of 10.9  J/cm2. A response surface model was developed to predict the ina...

Optimization of lipase production on agro-industrial residue medium by Pseudomonas fluorescens (NRLL B-2641) using response surface methodology

The aim of our research was to explore the most cost-efficient and optimal medium composition for the production of lipase from Pseudomonas fluorescens (NRLL B-2641) culture grown on sunflower oil cake (SuOC) by applying response surface methodology (RSM). The oil cake was used instead of carbon sources. Peptone, ammonium sulphate and the carbon source (SuOC) were the most important factors as it is obligatory for microbial growth. Subsequently, the optimum values for the carbon source, peptone and ammonium sulphate were found to be 11.10% (w/v), 1.18% (w/v) and 0.83% (w/v), respectively. Experiments carried out under optimum conditions revealed a maximum lipase activity of 10.8 U mL−1, which was achieved after 48 h of fermentation. The obtained results were finally verified with batch experiments carried out under the optimum conditions evaluated and it was demonstrated that the SuOC from agro-industrial residue as substrates can be used as an inexpensive base (carbon source) for the production of lipase by P. fluorescens (NRLL B-2641).