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Non-sterile heterotrophic cultivation of native wastewater yeast and microalgae for integrated municipal wastewater treatment and bioethanol production

Lookup NU author(s): Dr Sharon Velasquez OrtaORCiD, Dr Peter Leary



This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND).


© 2019Currently over 80% of wastewater generated globally, is discharged into surface waters without adequate treatment. Major environmental and public health risks associated with such releases are particularly prevalent in developing countries where the infrastructure and financing for effective treatment is lacking. Novel low cost integrated wastewater treatment and biorefinery processes could provide a sustainable solution. This study investigated, for the first time, the feasibility of simultaneous wastewater treatment and bioethanol production in non-sterile, heterotrophic bioreactors using either microalgae, wild yeast, or a co-culture of microalgae and wild yeast. Scenedesmus sp. are known to achieve high biomass concentrations under sterile heterotrophic conditions. However, under the non-sterile conditions proposed, relatively low nutrient removal rates (60% nitrate, 53% total ammonia nitrogen (TAN) and 46% orthophosphate) and biomass yields (0.98 ± 0.10 g/L) were achieved. Wastewater grown microalgae and yeast co-cultures achieved high nutrient removal rates (96% nitrate, 100% TAN and 93% orthophosphate). Wastewater grown yeast cultures produced consistently promising results, achieving high biomass concentrations of 3.7 ± 0.1 and 4.2 ± 0.1 g/L along with 100% nitrate, 100% TAN and 92.6% orthophosphate removal. Yeast provided the additional advantage of aerobic fermentation, possibly allowing integrated wastewater treatment and bioethanol production.

Publication metadata

Author(s): Walls L, Velasquez-Orta SB, Romero-Frasca E, Leary P, Noguez IY, Ledesma MT

Publication type: Article

Publication status: Published

Journal: Biochemical Engineering Journal

Year: 2019

Volume: 151

Online publication date: 15/11/2019

Acceptance date: 25/07/2019

Date deposited: 22/10/2019

ISSN (electronic): 1369-703X

Publisher: Elsevier


DOI: 10.1016/j.bej.2019.107319


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