The inhibitory effects of simulated light sources on the activity of algae cannot be ignored in photocatalytic inhibition

Dongpeng Li; Yifei Wang; Xinshan Song; Mengqi Jiang; Xiaoxiang Zhao; Xin Cao

doi:10.1016/j.chemosphere.2022.136611

The inhibitory effects of simulated light sources on the activity of algae cannot be ignored in photocatalytic inhibition

Chemosphere. 2022 Dec;309(Pt 1):136611. doi: 10.1016/j.chemosphere.2022.136611. Epub 2022 Sep 27.

Authors

Dongpeng Li¹, Yifei Wang¹, Xinshan Song¹, Mengqi Jiang², Xiaoxiang Zhao¹, Xin Cao³

Affiliations

¹ Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China.
² Center for Ecological Research, Kyoto University, Shiga, 520-2113, Japan.
³ Textile Pollution Controlling Engineering Center of Ministry of Environmental Protection, College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China. Electronic address: caoxin@dhu.edu.cn.

PMID: 36179922
DOI: 10.1016/j.chemosphere.2022.136611

Abstract

Harmful algal blooms (HABs) destroy the balance of the aquatic ecosystem, causing huge economic losses and even further endangers human health. In addition to traditional methods of algae removal, photocatalytic inhibition of algae is drawing more and more interests with rich application scenarios and considerable potential. Simulated visible light sources are used to excite photocatalytic materials and optimize their performance. However, most of the light irradiation intensities used in the study exceeded 50 mW/cm². And the effects of intense light irradiation conditions on algal growth have rarely been addressed in previous studies. So we focused on the effect of different intensity of light irradiation on the growth of algae. We explored the relationship between light irradiation intensity and algal inactivation rate, and investigated the changes in ROS levels in algal cells under different light irradiation and the resulting response of the antioxidant system. We have found that several major antioxidant enzyme activities, such as SOD and CAT, were significantly higher and lipid peroxidation products (MDA) were accumulating. Intense light irradiation had the most direct effect on the photosynthetic system of algal cells, with the photosynthetic rate and relative electron transfer rate decaying to almost 0 within 30 min, indicating that algal photosynthesis was inhibited in a fairly short period of time. We further observed the physiological and morphological changes of algal cells during this process using TEM and found that the progressive dissolution of the cell membrane system and the damage of organelles associated with photosynthesis play a major role in promoting cell death. We thus conclude that light irradiation has a significant effect on the physiological activity of algal cells and is a non-negligible factor in the study of photocatalytic removal of harmful algae. It will provide theoretical guidance for the future study of photocatalysis on algae inhibition.

Keywords: Algae inactivation; Light irradiation; Lipid peroxidation; Photosynthetic system.

MeSH terms

Antioxidants*
Ecosystem*
Harmful Algal Bloom
Reactive Oxygen Species / metabolism
Superoxide Dismutase

Substances

Antioxidants
Reactive Oxygen Species
Superoxide Dismutase