Genetic Engineering of Nitrate Assimilation in Chlamydomonas reinhardtii to Accelerate Growth for Algal Wastewater Treatment

Helen Yu

doi:10.54254/2755-2721/2026.KA28543

Applied and Computational EngineeringOpen access

Genetic Engineering of Nitrate Assimilation in Chlamydomonas reinhardtii to Accelerate Growth for Algal Wastewater Treatment

Research Article

Open Access

Genetic Engineering of Nitrate Assimilation in Chlamydomonas reinhardtii to Accelerate Growth for Algal Wastewater Treatment

Helen Yu ^1*

¹ Basis International School Hangzhou, Student, Hangzhou, Zhejiang, China

^*Corresponding author: helenfish0425@gmail.com

Published on 28 October 2025

ACE Vol.200

ISSN (Print): 2755-273X

ISSN (Online): 2755-2721

ISBN (Print): 978-1-80590-491-5

ISBN (Online): 978-1-80590-492-2

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Abstract

Algae-based wastewater treatment offers a sustainable alternative to conventional bacterial methods but is hindered by slow treatment times and difficulties in harvesting microscopic cells. Although photogranules, the clusters formed from the co-cultivation of the green alga Chlamydopodium sp. and the cyanobacterium Leptolyngbya PCC-6306, solve the harvesting issue, their structural stability depends on maintaining a precise 30:1 species ratio. This combination is inherently unstable due to the significantly faster growth rate of the cyanobacterium. The other bottleneck is the slow growth rate of the nutrient-absorbing green algae, which prolongs treatment time far beyond the standard 6-8 hours used in existing infrastructure. This research aims to overcome these two limitations by genetically enhancing nitrogen metabolism in a model green alga, Chlamydomonas reinhardtii (C.reinhardtii). To accelerate nitrogen uptake and conversion into biomass, thereby aligning algal growth rates with practical treatment timelines and stabilizing photogranule combinations, this experiment overexpresses key genes involved in nitrate assimilation: Nitrate Transporter (NRT1), Nitrate Reductase (NR), and Nitrite Reductase (NiR). We detailed the design of transformation plasmids and extensive efforts to isolate the target genes, and then updated the plan due to discoveries of the characteristics of the high-GC-content genome of C. reinhardtii. Successful target gene extraction proved challenging, leading to a recommendation for artificial gene synthesis in future work.

Keywords:

Algal Wastewater Treatment, Genetic Engineering, Chlamydomonas reinhardtii, Nitrogen Assimilation

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References

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References

[1]. Akinnawo, Solomon Oluwaseun. "Eutrophication: Causes, consequences, physical, chemical and biological techniques for mitigation strategies." Environmental Challenges 12 (2023): 100733.

[3]. Znad, Hussein, et al. "Bioremediation and nutrient removal from wastewater by Chlorella vulgaris." Ecological Engineering 110 (2018): 1-7.

[4]. Amaro, Helena M., et al. "Microalgae systems-environmental agents for wastewater treatment and further potential biomass valorisation." Journal of Environmental Management 337 (2023): 117678.

[9]. Sanz-Luque, Emanuel et al. “Understanding nitrate assimilation and its regulation in microalgae.” Frontiers in plant science vol. 6 899. 26 Oct. 2015, doi: 10.3389/fpls.2015.00899

[14]. Tomczuk, Marlena et al. “Gadolinium in the Environment: A Double-Edged Sword for Plant Growth and Ecosystem Stability.” Metabolites vol. 15, 6 415. 19 Jun. 2025, doi: 10.3390/metabo15060415

Cite this article

Yu,H. (2025). Genetic Engineering of Nitrate Assimilation in Chlamydomonas reinhardtii to Accelerate Growth for Algal Wastewater Treatment. Applied and Computational Engineering,200,76-90.

Data availability

The datasets used and/or analyzed during the current study will be available from the authors upon reasonable request.

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Volume title: Proceedings of CONF-MCEE 2026 Symposium: Advances in Sustainable Aviation and Aerospace Vehicle Automation

ISBN: 978-1-80590-491-5(Print) / 978-1-80590-492-2(Online)

Editor: Ömer Burak İSTANBULLU

Conference website: https://2025.confmcee.org/kayseri.html

Conference date: 14 November 2025

Series: Applied and Computational Engineering

Volume number: Vol.200

ISSN: 2755-2721(Print) / 2755-273X(Online)

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