Phycorefineries for Sustainable Wastewater Treatment and Resource Recovery

Inadequate treatment of wastewater remains a challenge globally, resulting in environmental pollution and public health risks. Likewise, various types of wastewaters released from municipal, industrial and agricultural streams can be rich sources of nutrients and organic content to generate biomass of phototrophic microorganisms which can be utilized for resource and energy recovery. Microbial phototrophs such as cyanobacteria, microalgae or diatoms can flourish well in such wastewaters due to their remarkable metabolic versatility enabling them to efficiently remove pollutants such as nitrogen, phosphorus, heavy metals, and emerging contaminants. Therefore, next-generation phycorefineries utilizing either cyanobacteria, microalgae, diatoms or their co-cultures offer a promising solution for wastewater treatment. In addition, their biomass can also be valorised into a spectrum of bioproducts such as pigments (such as phycobiliproteins, fucoxanthin, astaxanthin), exopolysaccharides, bioplastics, biofuels, bioenergy (including biogas), biodegradable nanomaterials, bio-stimulants and other high-value bioproducts.

However, several challenges related to genetic and phenotypic instability of phototrophic strains, ineffective removal of trace and persistent pollutants, scaling up of photobioreactors/raceway pond systems and optimization of biomass valorisation processes need to be addressed at various phases of technology development. To address these bottlenecks, advanced strain selection, metabolic engineering, systems microbiology, multi-omics and CRISPR-based genome editing can be utilized to improve treatment efficacy and bioproduct yields. Likewise, innovative hybrid cultivation modes combining phototrophic and heterotrophic processes, novel photobioreactor and raceway pond configurations, consortia engineering and interdisciplinary process modelling may also facilitate the scalability of phycorefinery systems. Overall, this collection aligns well with some of the Sustainable Development Goals (SDGs) such as SDG6 (Clean Water and Sanitation), SDG7 (Affordable and Clean Energy), SDG12 (Responsible Consumption and Production) and SDG13 (Climate Action).

This Research Topic invites contributions of Original Research articles, Reviews, Mini Reviews, Methods and Perspectives on cyanobacteria, microalgae or diatoms based phycorefinery systems for sustainable wastewater treatment integrated with generation of high-value bioproducts and/or biofuels or bioenergy. Contributions may address, but are not limited to following research areas:

• Innovations in next-generation phycorefineries: strain selection, engineering and process design within a circular bio-based economy framework for multiproduct recovery.

• Development of cyanobacterial, microalgae, diatoms or co-culture systems for removal of emerging contaminants, microplastics, heavy metals, antibiotics and/or antibiotic resistance from wastewaters.

• Elucidating metabolic pathways for biodegradation of wastewater pollutants and nutrient removal in photoautotrophic microorganisms.

• Metabolic engineering of phototrophs for improved treatment performance or targeted bioproduct generation.

• Cyanobacterial, microalgal or diatom biomass valorisation into biofuels and/or bio-stimulants, pigments, bioplastics, nutraceuticals and/or other high-value products.

• Engineering hybrid photobioreactor/raceway pond designs, phycorefinery cascades to achieve improved process efficiency.

• Phycorefinery process optimization by modulating carbon dioxide capturing, nutrients and light regimes to maximize biomass productivity and/or bio-product recovery.

• Nanobiotechnological applications of wastewater derived biomass of cyanobacteria, microalgae or diatoms.

Please note that Microbiotechnology does not consider descriptive studies that are solely based on amplicon (e.g., 16S rRNA) profiles or comparisons of nucleic acid extracts (e.g., metagenomics), unless they are accompanied by a clear hypothesis and experimentation and provide insight into the microbiological system or process being studied.

Article types and fees

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Editorial
• FAIR² Data
• Hypothesis and Theory
• Methods
• Mini Review
• Opinion
• Original Research
• Perspective
• Review
• ... View all formats

Articles that are accepted for publication by our external editors following rigorous peer review incur a publishing fee charged to Authors, institutions, or funders.

Article types

This Research Topic accepts the following article types, unless otherwise specified in the Research Topic description:

• Editorial
• FAIR² Data
• Hypothesis and Theory
• Methods
• Mini Review
• Opinion
• Original Research
• Perspective
• Review
• Systematic Review
• Technology and Code

Keywords: Phycorefinery, wastewater treatment, phototrophic microorganisms, high-value bioproducts, biofuels, strain improvement, metabolic engineering, systems microbiology, circular economy, environmental sustainability.

Important note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.