Characterization of mercury resistant and growth promoting Enterobacter sp. from rhizosphere to use as a biofertilizer
Abstract
Background: Mercury occurs naturally in environment, it is heavy metal that exists in three chemical forms like elemental mercury, inorganic mercury and organic mercury. All forms of mercury are problematic for living organism. Currently, the contamination of agricultural land and water systems with mercury has become one of the major environmental issues. The cheapest mode to remove mercury metal and its other forms from the ecosystem is the use of microorganisms.
Methods: In this study, initially bacterial species were isolated and purified from nodule like structures on roots and stems of plants on MacConkey agar medium. Further screening for resistance to mercury was done on N- agar medium supplemented with different concentration of HgCl2 (20, 30, 40 and 50 µg/mL). Well plate method was used for the determination of bacterial strains having maximum ability to detoxify mercury. Selected bacterial strains were subjected to different biochemical tests for characterization and other metabolic tests were also performed to characterize their capabilities.
Results: All strains were highly resistant to HgCl2 at the concentration of 20 µg/mL and moderately resistant at 30 µg/mL. Bacterial strain S-2 was moderately resistant and S-3 was least resistant at 40 µg/ml whereas S-2 was least resistant at 50 µg/ml. Selected bacterial strains were positive for nitrogen fixation and protease production, negative for phosphate solubilization but only S-1 was positive for hydrogen cyanide (HCN). Bacterial species were molecular characterized by 16S rDNA sequencing as Enterobacter cloacae (KJ857483, KJ857484 and KJ857485: NCBI GeneBank).
Conclusion: Selected Enterobacter sp. exhibiting multiple characteristics can be used as biofertilizer in mercury polluted land for sustainable agriculture.
Full Text:
PDFReferences
Tangahu BV, Abdullah SRS, Basri H, Idris M, Anuar N, et al. Phytoremediation of wastewater containing lead (Pb) in pilot reed bed using Scirpus grossus. International Journal of Phytoremediation, (2013); 15(7): 663-676.
Amin A, Latif Z. Phytotoxicity of Hg and its Detoxification through Microorganisms in Soil. Advancements in Life Sciences, (2015); 2(2): 98-105.
Zaidi A, Khan S. Interactive effect of rhizotrophic microorganisms on growth, yield, and nutrient uptake of wheat. Journal of plant Nutrition, (2005); 28(12): 2079-2092.
Kamran MA, Eqani SAMAS, Bibi S, Xu R-k, Monis MFH, et al. Bioaccumulation of nickel by E. sativa and role of plant growth promoting rhizobacteria (PGPRs) under nickel stress. Ecotoxicology and Environmental Safety, (2016); 126256-263.
Szymańska S, Płociniczak T, Piotrowska-Seget Z, Złoch M, Ruppel S, et al. Metabolic potential and community structure of endophytic and rhizosphere bacteria associated with the roots of the halophyte Aster tripolium L. Microbiological Research, (2016); 18268-79.
van Dijk K, Nelson EB. Fatty acid competition as a mechanism by which Enterobacter cloacae suppresses Pythium ultimum sporangium germination and damping-off. Applied and Environmental Microbiology, (2000); 66(12): 5340-5347.
Zeroual Y, Moutaouakkil A, Blaghen M. Volatilization of mercury by immobilized bacteria (Klebsiella pneumoniae) in different support by using fluidized bed bioreactor. Current Microbiology, (2001); 43(5): 322-327.
Amin A, Latif Z. Detoxification of mercury pollutant by immobilized yeast strain Candida xylopsoci. Pakistan Journal of Botany, (2013); 45(4): 1437-1442.
Scherrer R. Gram's staining reaction, Gram types and cell walls of bacteria. Trends in Biochemical Sciences, (1984); 9(5): 242-245.
Ahmad F, Ahmad I, Khan M. Screening of free-living rhizospheric bacteria for their multiple plant growth promoting activities. Microbiological Research, (2008); 163(2): 173-181.
Cappuccino JG, Sherman N. In Microbiology: a laboratory manual. (2008); p 9; Pearson/Benjamin Cummings. England
Joshi GK, Kumar S, Sharma V. Production of moderately halotolerant, SDS stable alkaline protease from Bacillus cereus MTCC 6840 isolated from lake Nainital, Uttaranchal state, India. Brazilian Journal of Microbiology, (2007); 38(4): 773-779.
Ono BI, Kijima K, Ishii N, Kawato T, Matsuda A, et al. Regulation of sulphate assimilation in Saccharomyces cerevisiae. Yeast, (1996); 12(11): 1153-1162.
Amin A, Latif Z. Isolation and characterization of H2S producing yeast to detoxify mercury containing compounds. International Research Journal of Microbiology, (2011); 2517-525.
Teng Y, Wang X, Li L, Li Z, Luo Y. Rhizobia and their bio-partners as novel drivers for functional remediation in contaminated soils. Frontiers in Plant Science, (2015); 6.
Sedgley C, Samaranayake L. Antimicrobial susceptibility of oral isolates of Enterobacter cloacae and Klebsiella pneumoniae from a southern Chinese population. Oral Microbiology and Immunology, (1998); 13(5): 315-321.
Sy A, Giraud E, Jourand P, Garcia N, Willems A, et al. Methylotrophic Methylobacteriumbacteria nodulate and fix nitrogen in symbiosis with legumes. Journal of Bacteriology, (2001); 183(1): 214-220.
Sinha A, Kumar S, Khare SK. Biochemical basis of mercury remediation and bioaccumulation by Enterobacter sp. EMB21. Applied Biochemistry and Biotechnology, (2013); 169(1): 256-267.
Mehnaz S, Baig DN, Lazarovits G. Genetic and phenotypic diversity of plant growth promoting rhizobacteria isolated from sugarcane plants growing in Pakistan. Journal of Microbiology and Biotechnolology, (2010); 20(12): 1614-1623.
Refbacks
- There are currently no refbacks.