Bioremoval of Co(II) by a novel halotolerant microalgae Dunaliella sp. FACHB-558 from saltwater

Chenglong Liu; Xueer Wen; Huiqiao Pan; Ying Luo; Junyang Zhou; Yuzhe Wu; Zhiyong Zeng; Ting Sun; Jun Chen; Zhangli Hu; Sulin Lou; Hui Li

doi:10.3389/fmicb.2024.1256814

Bioremoval of Co(II) by a novel halotolerant microalgae Dunaliella sp. FACHB-558 from saltwater

Front Microbiol. 2024 Apr 30:15:1256814. doi: 10.3389/fmicb.2024.1256814. eCollection 2024.

Authors

Chenglong Liu^{1

2}, Xueer Wen¹, Huiqiao Pan³, Ying Luo¹, Junyang Zhou¹, Yuzhe Wu¹, Zhiyong Zeng^{1

2}, Ting Sun¹, Jun Chen¹, Zhangli Hu¹, Sulin Lou¹, Hui Li¹

Affiliations

¹ Guangdong Engineering Research Center for Marine Algal Biotechnology, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.
² Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, China.
³ Department of Embryology, Carnegie Institution for Science, Baltimore, MD, United States.

Abstract

Cobalt pollution is harmful to both the aquatic ecosystem and human health. As the primary producer of aquatic ecosystems in hypersaline environments, unicellular planktonic Dunaliella microalgae is considered to be a low-energy and eco-friendly biosorbent that removes excess cobalt and enhances the vitality of coastal and marine ecosystems. In this study, we found that the halotolerant microalga named Dunaliella sp. FACHB-558 could grow under a salinity condition with 0.5-4.5 M NaCl. A phylogenetic analysis based on the rbcL gene revealed that Dunaliella sp. FACHB-558 is a close relative of Dunaliella primolecta TS-3. At lab-scale culture, Dunaliella sp. FACHB-558 exhibited high tolerance to heavy metal stresses, including cobalt, nickel, and cadmium. Treatment with 60 μM cobalt delayed its stationary phase but ultimately led to a higher population density. Furthermore, Dunaliella sp. FACHB-558 has the ability to adsorb the cobalt ions in the aquatic environment, which was evidenced by the decreased amount of cobalt in the culture medium. In addition, the tolerance of Dunaliella sp. FACHB-558 to cobalt stress was correlated with enhanced nitric oxide content and peroxidase activity. The autophagy inhibitor 3-MA enhanced nitric oxide burst, increased peroxidase activity, and accelerated the bioremoval of cobalt, suggesting that the autophagy pathway played a negative role in response to cobalt stress in Dunaliella sp. FACHB-558. In summary, our study identified a novel microalga possessing high cobalt tolerance and provided a promising natural biosorbent for the research and application of heavy metal bioremediation technology.

Keywords: Dunaliella; biosorbent; cobalt; environmental pollution; heavy metal; microalgae.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This research was supported by China National Key Research and Development Project (No. 2023YFF1001202 and 2018YFA0902500), The Project of DEGP (No. 2023ZDZX4047), Guangdong Natural Science Foundation (No. 2021A1515011590) and Guangdong Province Key Research and Development Project (No. 2022B1111070005). The authors gratefully acknowledge the supports from Instrumental Analysis Center of Shenzhen University.