T1b1 Experiment

Different batch experiments were conducted to access the effect of pH on removal of heavy metals by T1B1 strain. 100 ml of sterilized SE medium was inoculated into 250 ml Erlenmeyer flask containing 100 µl (107cells/ml) of bacterial suspension with HM (mg L-1): Fe (150), Mn (100), Ni (50), Cd (30), Cu (30) and Zn (50) with pH adjusted to 4, 6.5 and 9. Another set of experiments were set up by inoculating SE medium containing HMs (mg L-1 ): Cr+6 (100, 150, 200), Fe (100, 150, 200), Ni (50, 100, 150), Cu (30, 60, 90), Zn (50, 100 , 150), Mn (50, 100, 150), Cd (30, 60, 90) with pH adjusted to 7. All flasks were incubated in a rotary shaker at 150 rpm at 37ºC for 48h. All experiments were conducted in triplicate. To determine the HM removals by the strain, 1ml of the medium was …show more content…
Shoot length, root length, fresh weight and dry weight (80ºC for 24 h until a constant weight) were measured. 1 gm leaf sample was taken and chlorophyll a+b, carotenoids were measured (Aron, 1949). For biochemical analysis, 1 gm ground leaf sample was homogenized in 2 ml of 0.1 M ice cooled phosphate buffer containing 0.1 mM ethylenediamine tetra acetic acid and 1% (w/v) polyvinylpyrrolidone and inoculated 30 min in ice. This homogenate sample was centrifuged at 10000 rpm for 30 min at 4ºC and supernatant collected. The supernatant was assayed for Catalase (CAT), Superoxide dismutase (SOD), Malondialdehyde (MDA) and soluble protein with standardized protocol. For HM analysis, shoot and root samples were digested with 1:3 (v/v) HNO3: HCl and concentration determined by AAS. Efficiency of phytoremediation was determined by calculating bio concentration factor (BCF), the capacity of the plant uptake of HM from soil to plant roots ( Ghosh and Singh, 2005) and translocation factor (TF) for transfer from roots to shoot (Yoon et al.,