Abstract:
Remediation of hexavalent chromium with conventional chemical and physical methods is a costly
process, while replacing some critical steps in physiochemical remediation with self-sustaining bioremediation
agents are expected to be cost-effective and environmentally friendly implementation.
In this study, a microalga isolated from a freshwater stream receiving treated textile
wastewater was identified up to its molecular level and investigated its ability to tolerate and
remove hexavalent chromium from extremely acidic conditions under different temperatures. The
ability of microalgae to tolerate and remove Cr(VI) was investigated by growing it in BG11 media
with different pH (1, 2, 3 & 7), amended with several concentrations of Cr(VI) and incubated under
different temperatures for 96 hrs. Microalga was identified as Chlorella vulgaris and found that the
isolated strain has a higher hexavalent chromium removal potential in extremely acidic conditions
than in neutral pH conditions at 25 C. In contrast, its Cr(VI) removal potential is significantly influenced
by the pH and temperature of the growth medium. Furthermore, it exhibited a permanent
viability loss at extreme acidic conditions (pH 1 3) and prolonged exposure to the higher chromium
content. The microalga investigated will be a highly useful bioagent in hexavalent chromium
remediation in high acidic conditions.
