Evaluating Bioflocculation Harvesting of Freshwater and Marine Microalgae Using Exopolysaccharides (EPSs) from <i>Klebsiella</i> sp.

The rising global energy demand and environmental concerns associated with fossil fuels have intensified interest in sustainable biofuel sources, with microalgae emerging as a viable candidate due to its high biomass yield and efficient CO<sub>2</sub> conversion. However, the economic fe...

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Bibliographic Details
Main Authors: Yicheng Yuan, Jingxuan Lu, Quan Wang
Format: Article
Language:English
Published: MDPI AG 2024-12-01
Series:Separations
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Online Access:https://www.mdpi.com/2297-8739/11/12/355
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Summary:The rising global energy demand and environmental concerns associated with fossil fuels have intensified interest in sustainable biofuel sources, with microalgae emerging as a viable candidate due to its high biomass yield and efficient CO<sub>2</sub> conversion. However, the economic feasibility of microalgal biofuels is currently challenged by costly harvesting processes. This study investigates the use of exopolysaccharides (EPSs) derived from <i>Klebsiella</i> sp. as an environmentally friendly bioflocculant for harvesting two microalgae species: <i>Raphidocelis subcapitata</i> and <i>Dunaliella salina</i>. Comparative flocculation experiments revealed that <i>Klebsiella</i> EPS promotes efficient aggregation in <i>R. subcapitata</i>, achieving over 90% flocculation efficiency, while performance with <i>D. salina</i> was impacted by high salinity, which reduced charge neutralization and bridging effects. Structural analyses using FTIR, 3D-EEM, CLSM, and XPS elucidated the EPS composition, underscoring the roles of polysaccharides and proteins in facilitating microalgal aggregation. The findings indicate that <i>Klebsiella</i> EPS offers a sustainable alternative to chemical flocculants, supporting eco-friendly biofuel production and potential applications in wastewater treatment. This approach provides insights into optimizing EPS-based flocculation for diverse environmental conditions, paving the way for more sustainable biomass recovery practices.
ISSN:2297-8739