Occurrence of heavy metal‐resistance in microflora from serpentine soil of Andaman

Abstract

Serpentine soils collected from Saddle Hills, Chidyatapu and Rutland of Andaman Islands, India were analyzed for physico-chemical and microbiological characteristics and compared with those from adjacent non-serpentine localities. The serpentine soils contained high levels of nickel (1740.0-8033.4 mg/kg dry soil), cobalt (93.2-533.4 mg/kg dry soil) and chromium (302.9-4437.0 mg/kg dry soil), in addition to 62-152 g of iron and 37-60 g of magnesium per kg dry soil. Characteristically the serpentine soils showed low microbial density (6.2-11.3 x 10(6) colony forming unit/g soil) and activity (1.7-3.5 microg fluorescein/g dry soil/h) than non-serpentine outcrops. Serpentine microbial population was dominated by bacteria which represented 5.12 to 9.5 x 10(6) cfu/g of soil, while the fungal population ranged from 0.17 to 3.21 x 10(6) cfu/g of soil. A total of 342 (200 from serpentine and 142 from non-serpentine soils) isolates were compared for Ni, Co and Cr resistance. Serpentine microflora was in general, highly resistant than non-serpentine ones and showed a metal-resistance profile of Cr > Ni > Co. Amongst the serpentine isolates, 8 and 11 bacteria tolerated > 12.0 mM Ni and > 16.0 mM Cr respectively, while 6 fungal isolates showed a minimum inhibitory concentration (MIC) value > 8.0 mM Co. These 25 serpentine strains also showed co-resistance to Cu, Zn and Mn but were sensitive to Hg and Cd. The selected bacterial isolates were resistant to ampicillin, penicillin G and polymyxin B, whereas fungal strains showed resistance to amphotericin B, nystatin and fusidic acid.

Effect of button mushroom compost on mobilization of heavy metals by sunflower

“…Generally microorganisms isolated from heavy metals contaminated soils possess the ability to withstand against multiple pollutants as they have adapted to such environments (Pal et al, 2005;Abou-Shanab et al, 2007). Remedation of heavy metal contaminated soil have been employed with both microorganism and phytoextraction.…”

Influence of metal resistant-plant growth-promoting bacteria on the growth of Ricinus communis in soil contaminated with heavy metals

“…This high tolerance to heavy metals could be attributed to the fact that the bacteria were isolated from a serpentine soil containing high levels of metals (Freitas et al, 2004). It is known that microorganisms isolated from natural environments contaminated with heavy metals often exhibit tolerance to multiple pollutants because they have adapted to such environments (Pal et al, 2005). Inoculation of metal resistant PGPB increased the growth of R. communis plants and it seemed it was effective in protecting plants from growth inhibition caused by heavy metals.…”

Characterization of Phosphate Solubilizing Bacteria Isolated from Mine Tailings of Zawar Mines, Udaipur, India

“…The highest MIC of 24mg/ml was exhibited by PSB 16 followed by 21mg/ml by PSB 11 and 15mg/ml by PSB 51. Pal et al, (2005) isolated a total of 342 isolates from serpentine and non-serpentine soils of Andaman Islands, India and compared their Ni, Co and Cr resistance. They reported that serpentine microflora was highly resistant than non-serpentine ones and showed a metalresistance profile of Cr > Ni > Co.…”