Effect of chromium (Vi) reducing bacillus species PZ3 on the growth of pea plants in chromium amended soil

Abstract

Use of Cr (VI) in various industries like leather, tanning, metallurgy, electroplating, textile and pigment manufacturing may lead to the contamination of the environment with Cr (VI). Aim of this study is to check the bacterial species for their tolerance towards multiple metals, antibiotics, plant growth promoting activity, Cr (VI) reducing activity and to further check its effect on pea growth in Cr (VI) contaminated soil. Bacterial strains were isolated from metal contaminated soils of Abeokuta, Ogun State, Nigeria. All of the isolates showed tolerance to lead, zinc and chromium (VI). All bacterial species were positive to ammonia, Bacillus PZ3 and Treptococcus spp. PZ4 were positive to HCN. Bacterial strains also showed reduction of chromium (VI) under varying pH and chromium concentration. Maximum reduction (87.5%) of chromium (VI) was observed at pH 7 by Bacillus PZ3. Chromium (VI) was also reduced significantly at pH 5, 6, 8 and 9. The PGPR strain PZ3 reduced chromium (VI) at a concentration of 50 μg Cr/mL (47.5%), 100 μg Cr/mL (87.5%) and 150 μg Cr/mL (133.33%). Chromium reducing Bacillus PZ3 when inoculated in chromium amended soil increased the growth, nodulation, leghaemoglobin, chlorophyll and protein content of pea plant in comparison to control plants.