Isolation and Screening of Chromium-Tolerant Bacteria from Wetland Rhizosphere for use in Sustainable Bioremediation

Title

Isolation and Screening of Chromium-Tolerant Bacteria from Wetland Rhizosphere for use in Sustainable Bioremediation

Creator

Dass, Priyanka; Sayantan, D.

Description

Heavy metal contamination by hexavalent chromium [Cr(VI)] remains a major ecological threat due to its toxicity and persistence. This study investigated chromium-tolerant rhizospheric bacteria associated with Typha domingensis collected from Doddagubbi Lake, Bengaluru. Twelve isolates were obtained and exhibited diverse colony morphologies, where Gram staining classified the isolates into six Gram-positive and six Gram-negative strains. Physiological screening revealed broad adaptability with several isolates (DL4, DL6, DL11) tolerating up to 7.5% NaCl and DL11 showing thermotolerance up to 50C. pH profiling indicated that multiple strains (DL2, DL4, DL6, DL7, DL8) sustained growth up to pH 10. Biochemical tests showed widespread catalase activity and notable proteolysis, citrate utilisation and amylase production. Molecular identification grouped the isolates into eight taxa, including Brevibacillus brevis, Bacillus subtilis, Paenibacillus cookii, Kocuria rhizophila and several Pseudomonas species. Chromium tolerance assays demonstrated clear differentiation between highly tolerant isolates (DL1, DL2, DL8, DL9), which showed uninterrupted growth from 10100 mg/L Cr(VI) and moderately tolerant isolates that declined beyond 60 mg/L. Quantitative OD??? measurements further confirmed that the highly tolerant group retained OD values >0.55 at 80100 mg/L, whereas sensitive strains dropped below 0.05. These results highlight the strong bioremediation potential of T. domingensisassociated rhizobacteria for Cr(VI)-contaminated environments. 2026, World Researchers Associations. All rights reserved.

Source

Research Journal of Biotechnology;Volume;21;Issue;5;pp.133-141

Date

01-01-2026

Publisher

World Researchers Associations

Subject

Bioremediation; Chromium Tolerance; Heavy Metal Contamination; Rhizospheric Bacteria; Typha domingensis

Coverage

Dass P., Department of Life Sciences, Christ University, Bangalore, 560029, India; Sayantan D., Department of Life Sciences, Christ University, Bangalore, 560029, India

Rights

Restricted Access; Hardcopy may be available in the library

Relation

ISSN: 9736263;

Format

online

Language

English

Type

Article

Identifier

https://doi.org/10.25303/215rjbt1330141

https://www.scopus.com/pages/publications/105035549275?origin=resultslist