Phenotypic and genomic analysis of multiple heavy metal–resistant Micrococcus luteus strain AS2 isolated from industrial waste water and its potential use in arsenic bioremediation
Multiple heavy metal–resistant bacterium, Micrococcus luteus strain AS2, was isolated from industrial waste water of District Sheikhupura, Pakistan. The isolated bacterium showed minimum inhibitory concentrations of 55 and 275 mM against arsenite and arsenate. The bacterial strain also showed resistance against other heavy metal ions, i.e., lead, cadmium, chromium, mercury, nickel, and zinc, apart from arsenic. The optimum temperature and pH were 37 °C and 7, respectively. The antioxidant enzymes such as catalase were significantly increased under arsenite stress. The increase in 43.9% of GSH/GSSG and 72.72% of non-protein thiol was determined under15 mM arsenite stress. Bacterial genome was sequenced through Illumina and Nanopore and genes related to arsenic and other heavy metals were identified and blast (tblastx) on NCBI. Through scanning electron microscopy, no morphological changes were observed in bacterial cells under arsenite stress. The peaks appeared in EDX showed that there is surface adsorption of arsenite in bacterial cell while it was confirmed from Fourier transformed infrared spectroscopy analysis that there is some interaction between arsenite and functional groups present on the surface of bacterial cell. The SDS-PAGE analysis of whole-cell proteins under 15 mM arsenite stress clearly revealed that there is upregulation of some proteins in ranged of 60 to 34 kDa. The bioremediation efficiency (E) of bacterial biomass was 72% after 2 h and 99% after 10 h. The bioremediation efficiency of bacterial biomass is an indicator for the isolated bacterium to employ as a potential candidate for the amelioration of sites contaminated with arsenic.
KeywordsArsenite Heavy metals Micrococcus luteus AS2 Antioxidant enzymes Bioremediation
The Higher Education Commission (HEC) provided funds to the first author to visit Denmark under IRSIP program.
Compliance with ethical standards
Conflict of interest
The authors declared that they have no conflict of interest.
This article does not contain any studies with human participants or animals performed by any of the authors.
- Cappuccino JG, Sherman N (2002) Microbiology: a laboratory manual, 6th ed. Pearson Education, Inc., California, USAGoogle Scholar
- Luck H (1974) In: Bergmeyer HU, Gawhn K (eds) Methods in enzymatic analysis. Academic Press, New York, pp 885–894Google Scholar
- Manzoor M, Abid R, Rathinasabapathi B, De Oliveira LM, da Silva E, Deng F, Rensing C, Arshad M, Gul I, Xiang P (2019) Metal tolerance of arsenic-resistant bacteria and their ability to promote plant growth of Pteris vittata in Pb-contaminated soil. Sci Total Environ 660:18–24PubMedCrossRefGoogle Scholar
- Shah AH, Shahid M, Khalid S, Shabbir NZ, Bakhat HF, Murtaza B, Farooq A, Akram M, Shah GM, Nasim W, Niazi NK (2019) Assessment of arsenic exposure by drinking well water and associated carcinogenic risk in peri-urban areas of Vehari. Pakistan Environ Geochem Health. https://doi.org/10.1007/s10653-019-00306-6
- Shakoori FR, Aziz I, Rehman A, Shakoori A (2010) Isolation and characterization of arsenic reducing bacteria from industrial effluents and their potential use in bioremediation of wastewater. Pakistan J Zool 42:331–338Google Scholar