Bioremediation of heavy metals (Cr6+ and Cu2+) through the activity and subproduct generation of native bacteria isolated from a highly contaminated environment in the South American Andes

Chambi Mamani C.; Zuñiga Enriquez M.; Pacheco Umpire P.B.; Ticona Cayte A.E.; Ranilla Falcon C.A.; Montalvo Andia J.P. · Bioresource Technology Reports (2025) · DOI: 10.1016/j.biteb.2025.102346

Resumen

Heavy metal pollution poses a major threat to human health and ecosystems due to its persistence and bioaccumulation. Bacterial bioremediation provides an efficient, eco-friendly, and cost-effective alternative. This study identified metal-tolerant bacteria from oxidative lagoons in the Andes Mountains (>2000 m a.s.l.), an extreme environment with high UV radiation. The isolated strains Proteus mirabilis (MZ831507), Halomonas campaniensis (MZ831340), and Bacillus pumilus (MZ831213) tolerated chromium concentrations above 2000 mg L−1. After 36 h, Cr(VI) reduction efficiencies at 30 mg L−1 reached 99.00 %, 98.68 %, and 98.28 %, respectively, with significant activity maintained at 60–100 mg L−1. Extracellular polymeric substance (EPS) production was optimized under varying time, pH, and temperature conditions, reaching 504.44 mg L−1 for P. mirabilis (120 h, pH 7, 37 °C) and 688.89 mg L−1 for H. campaniensis (96 h, pH 9, 37 °C). EPS showed strong Cu(II) adsorption, with maximum capacities of 23.33 and 75.88 mg g−1.

Instituciones: Universidad Nacional de San Agustín de Arequipa; Universidad Católica San Pablo