Biosorption of cyanate by two strains of Chlamydomonas reinhardtii: evaluation of the removal efficiency and antioxidants activity

Abstract

Two strains of the chlorophyte Chlamydomonas reinhardtii, a wild type (WT) and a transgenic strain (C.CYN) contained an exogenous cyanase gene (CYN), were used to investigate the growth and cyanate biosorption capability through the analysis of the adsorption equilibrium isotherm. The potential antioxidants activity of the algal strains was also investigated under cyanate concentration. The antioxidants activity of both C.CYN and WT were enhanced by the application of cyanate.

Two adsorption isotherm models and the sorption kinetics were used to check the efficiency of the cyanate removal process. The results showed the biosorbent efficiency of Chlamydomonas in the removal of KCNO from aqueous solution. The C.CYN strain has great efficiency to remove cyanate as compared to the WT. The maximum percentage of cyanate removal was 83.75% for the C.CYN and 50% for the WT as treated with 0.8 mg.ml⁻¹ KCNO. The data were adapted to the nonlinear Langmuir model on the basis of the coefficient of determination. The calculated q_max was 0.54 and 0.42 µg.mg⁻¹ for C.CYN and WT which correlated to the experimental one (0.67 and 0.4 µg.mg⁻¹, respectively). Our data highlight the application of the transgenic algal strain toward the removal of highly toxic materials as cyanate.

Novelty statement The main objective of this work is to find out an efficient genetically-modified Chlamydomonas strain to remove the highly toxic cyanate compound from contaminated area. Moreover, to evaluate the biosorption ability of this transgenic strain with its wild one via two adsorption isotherm (the Langmuir and Freundlich) models. Also, to estimate the antioxidants activity of these strains under the cyanate toxicity through four different assays.

Keywords:

• Freundlich
• Langmuir
• phycoremediation
• reactive oxygen species
• transgenic strain

Acknowledgment

We are thankful to Professor Mohammed Ismaeil (Botany Department, Faculty of Science, Mansoura University, Egypt) for providing the C. reinhardtii wild strain. We also thank Prof. Rashad Kebeish for technical guidance and support; and Mr. Maged Ismaiel for writing assistance.

Disclosure statement

No potential conflict of interest was reported by the author(s).