2.2. Isolation of high dye biodegrading bacteria and growth medium
The wastewater samples were obtained from a local textile company from Mersin (Turkey). The samples were serially diluted 10-fold. The diluted sample (0.1 mL) was spread on Petri plates containing molasses media with 25 mg/L dye. In the experiments molasses was used in the media as a carbon and energy source. The composition of the growth medium was molasses solution (nearly equivalent to 10 g/L sucrose), 1.0 g/L NH4SO4, and 0.5 g/L KH2PO4 (Aksu and Dönmez, 2000). Agar (15 g/L) was added to the plates. The pH of the growth medium was adjusted to 6 with 0.01 M sulfuric acid or 1 M sodium hydroxide solutions. The Petri plates were incubated at 30 ± 1◦C for 7 days. The bacterial colonies that appeared on the molasses medium agar plates were isolated and purified by streaking the cells repeatedly on the molasses medium agar plate with dye. The pure cultures were kept at 4◦C and were transferred to molasses media containing dye every 3 months.