A Cr(VI) reducing bacterial strain FM1 was isolated from heavy metal contaminated agricultural soil irrigated with tannery effluents of Jajmau, Kanpur (India), and was identified as Bacillus sp. on the basis of biochemical methods and 16S rDNA gene sequence analysis. FM1 strain was found to be resistant to some toxic heavy metals (Cr(VI), Cr(III), Cu²+, Co²+, Cd²+, Ni²+ and Zn²+) up to several fold concentrations to the normal levels occurring in highly polluted region. FM1 was resistant to very high concentration of Cr(VI) (1,000 mg/L) and completely reduced 100 mg/L Cr(VI) within 48 h. Factors (pH, temperature, initial Cr(VI) concentration) affecting Cr(VI) reduction under culture condition were also evaluated. Reduction was optimum at 37 °C and pH 8. Cr(VI) reduction was enhanced by addition of glucose. The presence of heavy metal cations, such as Cu²+, Co²+, Cd²+, Ni²+ and Zn²+ showed differential effect on reduction. Since strain FM1 could grow in the presence of significant concentrations of metals and due to high Cr(VI) reduction ability, this bacterium may be potentially applicable in Cr(VI) detoxification.

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The genotoxicity of industrial wastewaters from Jajmau (Kanpur), was carried out by Ames Salmonella/microsome test, DNA repair-defective mutants, and Allium cepa anaphase-telophase test. Test samples showed maximum response with TA98 strain with and without metabolic activation. Amberlite resins concentrated wastewater samples were found to be more mutagenic as compared to those of liquid-liquid extracts (hexane and dichloromethane extracts). The damage in the DNA repair defective mutants in the presence of Amberlite resins concentrated water samples were found to be higher to that of liquid-liquid-extracted water samples at the dose level of 20 μl/ml culture. Among all the mutants, polA exhibited maximum decline with test samples. Mitotic index (MI) of root tip meristematic cells of A. cepa treated with 5, 10, 25, 50, and 100 % (v/v) wastewaters were significantly lower than the control. Complementary to the lower levels of MI, the wastewaters showed higher chromosomal aberration levels in all cases investigated.

The metal binding capacity of Bacillus sp. FM1 isolated from soil irrigated with tannery effluent was assessed using synthetic metal solutions and tannery wastewater. Biosorption of Cr(VI) and Cu(II) ions from aqueous solutions using Bacillus was investigated as a function of pH, initial metal ion concentration and contact time. The optimum adsorption pH value observed for Cr(VI) and Cu(II) ions was 2 and 5, respectively. Metal ion uptake increased with increasing initial metal concentration but no significant difference was observed by increasing the time after 60 min. Maximum uptake capacity of chromium was estimated as 64.102 mg g(-1), and of copper to 78.125 mg g(-1). Equilibrium data were well described by the Langmuir and Freundlich adsorption relations. The presence of functional groups on the cell wall surface of the biomass that may interact with the metal ion was confirmed by Fourier Transform Infrared (FTIR) spectroscopy. The application of Bacillus to remove Cr(VI) and Cu(II) in tannery effluent revealed that the biomass was capable of removing both the metal ions. However, the biosorption performance was slightly lower compared to that of synthetic metal solutions. Several factors may be responsible for this difference. However, the most important factor appears to be the presence of other contaminants such as anions, organics, and other trace metals in the effluent.

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In both eukaryotic and prokaryotic cells, zinc (Zn) plays a significant role as a cofactor for many enzymes and is present in DNA-binding Zn-finger proteins. It also plays a key role in metabolism, mitosis, development, and mitochondrial activity. Zinc has been the second most common transition metal for living organisms and the only metal that occurs in all classes of enzymes. Zinc is abundantly present in the earth's crust, and the most commonly found forms in the soil include sphalerite, zinc silicate, zinc oxide, zinc phosphate, and zinc carbonate. It is typically present in soil at a concentration of 5-770 ppm, which may vary as various anthropogenic activities such as chemical fertilizer, galvanization, pharmaceutical waste, and other applications release zinc ion in soil. Zn deficiency has become a severe problem affecting nearly half of the world's population because the plants in Zn-deficient soils are actually low in Zn content. According to the World Health Organization report, the shortage of micronutrients like Zn is a significant challenge to global health and sustainability. Approximately, 50% of the soils in India have zinc deficiency that affect most crop production. The main reasons for the zinc deficiency are higher use of chemical fertilizers, intensive farming, and inadequate irrigation system resulting in reduced zinc content in Indian soils. Although some soil may contain adequate quantities of zinc to sustain crop growth, even then the crops have low zinc status because of the insoluble nature of the zinc found in the soil. This locked zinc can be accessible to plants to support optimal growth if an appropriate technology is developed for the same. Several bacteria, particularly those present in the rhizosphere, possess the ability to solubilize the unavailable forms of a metal and making them bioavailable to plants. Bacillus has been the most prevalent species in plant rhizospheres, accounting for up to 95% of Gram-positive rhizospheric population. Bacillus is one of the most widely studied genera and is known