In-vitro Cr (III) alleviation and the concurrent biochemical responses by Chlorella minutissima to establish its phycoremediation potential and biofuel prospects

Different microalgal species possess the proficiency of tolerating heavy metals and enhance certain metabolic processes under metal stress. This is a novel study on C. minutissima under Chromium (III) stress to determine the IC50 value for optimization, to evaluate its phycoremediation potential and biofuel prospects. Varied range of Chromium Sulfate (20-120 mg/L) exposure on C. minutissima presented an IC50 value of 83.78 mg/L and ICPMS data stated that C. minutissima was able to eliminate 96.5% of Cr (III) from the medium with a BCF value of 0.96 and a high TI value of 1.035, reflecting on the high Cr (III) resistance ability and remediation potential of the selected microalgal species. A higher biomass productivity was observed for stressed cells (17.92 mg/L/day) than control (15.42 mg/L/day). The lipid content and productivity in the metal treated cells was elevated (21.21% and 0.77 mg/L in control, 30.12% and 1.26 mg/L under stress, respectively) with simultaneous maintenance of growth and photosynthetic functions. GC-MS study indicated a rise in MUFA under Cr (III) stress. This study presents significant insights for further investigation in utilization of C. minutissima for integrated approaches toward Cr (III) bioremediation and biodiesel production. © 2025 Elsevier B.V., All rights reserved.