Accumulation of Fe-Al by Scirpus grossus Grown in Synthetic Bauxite Mining Wastewater and Identification of Resistant Rhizobacteria

摘要

A phytotoxicity study was conducted to determine the maximum accumulation of Fe and Al in Scirpus grossus and to isolate and identify the Fe-Al-resistant rhizobacteria from S. grossus roots. Plants were grown in artificial bauxite mining wastewater containing iron (Fe) and aluminum (Al) (at a mass ratio of 3: 1) with five different Fe-Al mixture concentrations (ranging from 90 mg/L Fe + 30 mg/L Al to 450 mg/L Fe + 150 mg/L Al) together with a plant control (without the addition of Fe and Al) for 102 days. Maximum metal accumulation in plants was 53,187mg Fe/kg and 8,864mg Al/kg (dry basis), which occurred on day 42 in the 450 mg/L Fe + 150 mg/L Al treatment. Approximately 27 rhizobacteria were isolated from roots of all the treatments on day 102. Among these, three isolates, identified as Bacillus cereus strain NII, Bacillus pumilus strain NII, and Brevibacterium sp. strain NII, showed high resistance and tolerance to the highest Fe-Al concentrations (i.e., 450 mg/L Fe + 150 mg/L Al) in the medium. Thus, they can be considered Fe-Al-resistant rhizobacteria, since they survived and tolerated the most in Fe-and Al-rich medium during screening.