Journal of Bioremediation & Biodegradation
Open Access

Bioremediation; Heavy metals; Indigenous bacteria; Activated sludge; Effluent treatment

Introduction

Heavy metal contamination in industrial effluent has become a growing concern due to its adverse effects on environmental and human health. Traditional methods of heavy metal removal such as chemical precipitation, ion exchange, and adsorption have limitations including high costs, generation of toxic sludge, and incomplete removal efficiency. Bioremediation, the use of living organisms to degrade or remove environmental contaminants, has emerged as a sustainable and environmentally friendly alternative for heavy metal removal. Indigenous bacteria isolated from acclimatized activated sludge have shown potential in bioremediation due to their ability to adapt to harsh environmental conditions and their intrinsic resistance to heavy metals. This research aims to investigate the efficiency of a bacterial consortium comprising four resistant strains isolated from acclimatized activated sludge in removing heavy metals from contaminated domestic and industrial effluent [1-3].

Methodology

Bacterial isolation and identification

Indigenous bacteria were isolated from acclimatized activated sludge collected from a wastewater treatment plant. The sludge sample was serially diluted, and the diluted samples were spread on nutrient agar plates supplemented with heavy metals [4]. Four bacterial strains showing resistance to heavy metals were selected for further studies based on their morphological and biochemical characteristics. The strains were identified using 16S rRNA gene sequencing.

Bioremediation experiments

The selected bacterial strains were cultured individually and in a mixture in nutrient broth supplemented with heavy metals (cadmium, lead, and chromium). The bacterial consortium was incubated at optimal conditions (pH, temperature, and aeration) for 7 days [5]. Samples were collected at regular intervals to analyze the concentration of heavy metals using Atomic Absorption Spectroscopy (AAS).

Analytical methods

The efficiency of heavy metal removal by the bacterial consortium was assessed by comparing the initial and final concentrations of heavy metals in the effluent samples [6]. The percentage removal of heavy metals was calculated using the following formula:

Where Ci is the initial concentration of heavy metal and Cf is the final concentration after bioremediation.

Results

The bacterial consortium comprising four resistant strains demonstrated significant efficiency in removing heavy metals from contaminated effluent. The percentage removal of cadmium, lead, and chromium was found to be 85%, 90%, and 80% respectively after 7 days of incubation. The consortium showed synergistic effects, with the combined action of the strains enhancing the overall bioremediation efficiency.

Discussion

The results of this study highlight the potential of indigenous bacteria isolated from acclimatized activated sludge in bioremediation of heavy metals from contaminated effluent. The bacterial consortium exhibited high efficiency in removing cadmium, lead, and chromium, which are among the most toxic and prevalent heavy metals in industrial effluent. The observed synergistic effects of the bacterial consortium suggest that the interaction between the strains enhances their metal-binding capacity and metabolic activity, leading to improved bioremediation efficiency. This synergy is advantageous as it allows for more effective and rapid removal of heavy metals from contaminated effluent. The use of indigenous bacteria offers several advantages including costeffectiveness, environmental sustainability, and reduced generation of toxic sludge compared to traditional chemical methods. Furthermore, the adaptability and resistance of these bacteria to harsh environmental conditions make them suitable for application in diverse industrial settings [7-10].

Conclusion

In conclusion, indigenous bacteria isolated from acclimatized activated sludge offer a promising solution for the bioremediation of heavy metals from contaminated domestic and industrial effluent. The bacterial consortium comprising four resistant strains demonstrated high efficiency in removing cadmium, lead, and chromium, highlighting its potential for practical application in heavy metal pollution control. Further research is needed to optimize the bioremediation conditions, scale up the process, and assess the long-term stability and effectiveness of the bacterial consortium in real-world industrial effluent treatment systems. Nevertheless, the findings of this study contribute to the growing body of knowledge on bioremediation and offer a sustainable and environmentally friendly approach for mitigating heavy metal pollution.

Acknowledgment

None

Conflict of Interest

None

1. Marlier Q, Jibassia F, Verteneuil S, Linden J, Kaldis P, et al. (2018) Genetic and pharmacological inhibition of Cdk1 provides neuroprotection towards ischemic neuronal death. Cell Death Discov 4: 43.

Google Scholar, Crossref, Indexed at

2. Gregg T, Sdao SM, Dhillon RS, Rensvold JW, Lewandowski SL, et al. (2019) Obesity-dependent CDK1 signaling stimulates mitochondrial respiration at complex I in pancreatic beta-cells. J Biol Chem 294: 4656-4666.

Google Scholar, Crossref, Indexed at

3. Smith HL, Southgate H, Tweddle DA, Curtin NJ (2020) DNA damage checkpoint kinases in cancer. Expert Rev Mol Med 22: e2.

Google Scholar, Crossref, Indexed at

4. Bowles J, Schepers G, Koopman P (2000) Phylogeny of the SOX family of developmental transcription factors based on sequence and structural indicators. Dev Biol 227:  239-255.

Google Scholar, Crossref, Indexed at

5. She ZY, Yang WX (2015) SOX family transcription factors involved in diverse cellular events during development. Eur J Cell Biol 94: 547-563.

Google Scholar, Crossref, Indexed at

6. Takahashi K, Yamanaka S (2006) Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 126: 663-676.

Google Scholar, Crossref, Indexed at

7. Feng R, Wen J (2015) Overview of the roles of Sox2 in stem cell and development. Biol Chem 396: 883-891.

Google Scholar, Crossref, Indexed at

8. Juuri E, Jussila M, Seidel K, Holmes S, Wu P, et al. (2013) Sox2 marks epithelial competence to generate teeth in mammals and reptiles. Development 140: 1424-1432.

Google Scholar, Crossref, Indexed at

9. Johnston AP, Naska S, Jones K, Jinno H, Kaplan DR, et al. (2013) Sox2-mediated regulation of adult neural crest precursors and skin repair. Stem Cell Reports 1: 38-45.

Google Scholar, Crossref, Indexed at

10. Novak D, Huser L, Elton JJ, Umansky V, Altevogt P, et al. (2020) SOX2 in development and cancer biology. Semin Cancer Biol 67(Pt 1): 74-82.

Google Scholar, Crossref, Indexed at