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Updated: Jun 10, 2026

Quantification of Heavy Metals and Other Inorganic Contaminants on the Productivity of Microalgae
Published on: July 10, 2015
Chlor(am)ination of algal bound extracellular polymeric substances and cellular responses during raw water
Qi Fu1, Tian-Yang Zhang1, Chao Zeng1
1State Key Laboratory of Water Pollution Control and Green Resource Recycling, Key Laboratory of Urban Water Supply, Water Saving and Water Environment Governance in the Yangtze River Delta of Ministry of Water Resources, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, PR China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, PR China.
Abstract:
Pre-chlorination is an economical strategy for algae control, yet extracellular polymeric substances (EPS) can compromise its reliability. This study elucidated how EPS molecular structure governs algal responses to free chlorine (FC) and monochloramine (MC) during stepwise EPS removal. Loosely bound EPS (LB-EPS) was a soluble, protein-rich, nitrogen-containing fraction, whereas tightly bound EPS (TB-EPS) formed a more structured polysaccharide and humic-like matrix. Reaction kinetics showed higher reactivity with FC than with MC; TB-EPS consumed FC faster than LB-EPS (3.20 × 10-2 v.s. 2.14 × 10-2 mg-1·L·min-1), while MC reactions were slower (5.81 × 10-3 for LB EPS and 6.24 × 10-3 mg-1·L·min-1 for TB-EPS). Chlor(am)ination reshaped EPS protein secondary structure, with FC producing larger decreases in the α-helix/(β-sheet + random coil) ratio (39.5% for LB-EPS and 28.6% for TB-EPS), indicating weakened protein-mediated cohesion and enhanced EPS detachment. In algae assays, EPS removal accelerated intracellular oxidative stress and photosystem II (PSII) impairment before membrane permeabilization. Superoxide (O2•-) increased under FC by 59.4% without LB-EPS and 201.8% without B-EPS, and under MC by 110.3% and 500%, respectively, accompanied by stronger antioxidant enzyme responses under MC. These results highlight B-EPS as a key regulator of oxidant demand and stress buffering, guiding pre-chlorination designs for non-lytic inactivation.
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