This study aimed to evaluate three heavy metal tolerant bacterial strains (HMTB) namely Alcaligenes faecalis
MG257493.1, Bacillus cereus MG257494.1 and Alcaligenes faecalis MG966440.1 as antioxidant agents and plant
growth promotors under laboratory conditions. Their abilities to inhibit 2,2-DiPhenyl-2-Picrylhydrazyl hydrate
(DPPH) as non-enzymatic antioxidant activity and produce plant growth promoters (indole acetic acid (IAA),
gibberellins (GA3), salicylic acid (SA), proline (Pro.), sidrophores, exopolysaccharide (EPS) and biosurfactant)
were estimated in presence of four heavy metals Zinc (Zn2+) cadmium (Cd2+), copper (Cu2+) and lead (Pb2+) at
1000 and 1500 mg/l. Results showed that the antioxidant activities of three strains were increased with the
increasing of heavy metals concentration. All tested strains were able to produce all estimated plant growth
promoters in the presence or absence of heavy metals and the highest amounts of all compounds were recorded
in media free of heavy metals and decreased with the increasing of heavy metals concentration. Also, results
proved that the three evaluated strains were considered as heavy metal tolerant-plant growth promoting bacteria
(HMT-PGPB) and have beneficial characteristics for remediating the contaminated mine tailing soil |
