Inhibition mechanisms of high salinities on flocculation of marine Algal-Mycelial pellets

Sujie Li; Shuyi Xie; Yuting Yang; Xunan Yang; Yaobin Lu; Lijuan Luo; Shanshan Chen; Tiangang Luan

Current Research in Biotechnology (Jan 2024)

Inhibition mechanisms of high salinities on flocculation of marine Algal-Mycelial pellets

Sujie Li,
Shuyi Xie,
Yuting Yang,
Xunan Yang,
Yaobin Lu,
Lijuan Luo,
Shanshan Chen,
Tiangang Luan

Affiliations

Sujie Li: Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang 515200, China; Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
Shuyi Xie: Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang 515200, China; Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
Yuting Yang: Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang 515200, China; Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
Xunan Yang: Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, State Key Laboratory of Applied Microbiology Southern China, Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510006, China
Yaobin Lu: Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang 515200, China; Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
Lijuan Luo: Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang 515200, China; Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China
Shanshan Chen: Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang 515200, China; Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; Corresponding authors at: Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang 515200, China.
Tiangang Luan: Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang 515200, China; Guangdong Provincial Key Laboratory of Water Quality Improvement and Ecological Restoration for Watersheds, School of Ecology, Environment and Resources, Guangdong University of Technology, Guangzhou 510006, China; School of Environmental and Chemical Engineering, Wuyi University, Jiangmen 529020, China; Corresponding authors at: Guangdong Provincial Laboratory of Chemistry and Fine Chemical Engineering Jieyang Center, Jieyang 515200, China.

Journal volume & issue: Vol. 7
p. 100222

Abstract

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Microalgae are widely used in wastewater treatment because they can absorb nitrogen and phosphorus pollutions and reduce CO2 emissions. However, they are hard to collected due to tiny cell sizes. Flocculation of microalgae by fungi to form the algal-mycelial pellets (AMPs) is one of the efficient collecting methods from wastewater. With the large amount of saline wastewater being discharged, the flocculating effects and mechanisms of AMPs in high saline wastewater are still unknown. Flocculation experiments were performed by Aspergillus niger and Chlorella sp. to study the effects and mechanisms in 0 %-4% salinities. Results showed that the flocculating efficiency (FE) in the 0 %–2% salinities exceeded 95 % at 24 h, whereas the FE reached only 63 % ± 2 % in the 4 % salinity. The flocculating biomass were also decreased with the increasing salinity. Fungi pellets increased in volume and mass at high salinity, resulting in a more compact mycelium structure with less space for microalgae to attach, which was not conducive to flocculation. Furthermore, contents of proteins (PN) and polysaccharides (PS) in the tightly bound EPS (TB-EPS) of AMPs at 4 % salinity decreased by 44 % ± 8 % and 33 % ± 4 % respectively compared to those at 0 % salinity. The decrease in the content of PN and PS led to a weakening of hydrophobicity, a rise in electrostatic repulsion, and an increase in the energy barrier of AMPs, all of which impeded flocculation. This study will provide theoretical bases for the treatment and the recovery of microalgae in high saline wastewater.

Published in Current Research in Biotechnology

ISSN: 2590-2628 (Online)
Publisher: Elsevier
Country of publisher: Netherlands
LCC subjects: Technology: Chemical technology: Biotechnology
Website: https://www.journals.elsevier.com/current-research-in-biotechnology

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