Effect of arsenic accumulation on growth and antioxidant defense system of Chlorella thermophila SM01 and Leptolyngbya sp. XZMQ

• Published in: Algal research (Amsterdam) 2022-07, Vol.66, p.102762, Article 102762
• Main Authors: Mao, Qing, Xie, Zuoming, Irshad, Sana, Zhong, Zhaoqi, Liu, Taikun, Pei, Fuwen, Gao, Ban, Li, Liushuang
• Format: Article
• Language: English
• Subjects: Antioxidant; Arsenite; Bioaccumulation; Microalgae
• ISSN: 2211-9264; 2211-9264
• DOI: 10.1016/j.algal.2022.102762

Arsenic pollution is an environmental problem of concern, and algae have shown great potential for its application in bioremediation of arsenic pollution. The growth and antioxidative responses of Chlorella thermophila SM01 (C. thermophila SM01) and Leptolyngbya sp. XZMQ newly isolated from Shimen mine area were investigated in the presence of 0.5–10 mg As(III) L−1. After 3 d of exposure, the growth of C. thermophila SM01 and Leptolyngbya sp. XZMQ was inhibited in 0.5–10 mg As(III) L−1. The malondialdehyde (MDA) contents in the both species algal cell were elevated. The antioxidant enzyme activities (SOD, CAT) and the antioxidant content (GSH) in the cells were enhanced. However, with the extension of exposure time, they showed a downward trend. On the 15th day, they decreased to the lowest but still higher than the control. For C. thermophila SM01, 94.37% conversion of As(III) transformed to As(V) was obtained for initial As(III) concentration of 10 mg L−1 within 2 days. C. thermophila SM01 and Leptolyngbya sp. XZMQ could accumulate 1586.65, 2429.90 μg As g−1 dry weight in 10 mg As(III) L−1 solution, respectively. The shift in FTIR spectra indicated amide, carboxyl, and hydroxyl functional groups were involved in the adsorption of arsenic by algae. Principal component analysis (PCA) and Pearson's correlation indicated that antioxidant system and accumulation were negatively related to OD, biomass, Chl a for C. thermophila SM01. However, for Leptolyngbya sp. XZMQ, it was no correlation between MDA and indicators of OD, biomass, Chl a after 15 days. These results showed that C. thermophila SM01 and Leptolyngbya sp. XZMQ have different As(III) toxicity responses and bioaccumulation ability. The study provided a reference for exploring the role of algae in arsenic geochemical cycle in Shimen mining area. It is significant for further understanding the mechanism of algal bioremediation of arsenic polluted water environments. [Display omitted] •New algae (Chlorella. thermophila SM01 and Leptolyngbya sp. XZMQ) were identified from Shimen realgar mine.•94.37% oxidation of 10 mg L−1As(III) within 2 days to C. thermophila SM01•-NH2, -COOH and -OH were involved in the adsorption of arsenic by algae.•Synergy between antioxidant enzymes and GSH of two algae for arsenic detoxification•Leptolyngbya sp. accumulated maximum 2429.90 μg As g−1 dry weight.