Towards a sustainable supply of omega-3 fatty acids: Screening microalgae for scalable production of eicosapentaenoic acid (EPA)

Wenjia Gu,John M Kavanagh,Dale D Mcclure

doi:10.1016/j.algal.2021.102564

Wenjia Gu, John M Kavanagh + Show 1 more

Open Access

https://doi.org/10.1016/j.algal.2021.102564

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Journal: Algal Research	Publication Date: Nov 24, 2021
Citations: 14	License type: cc-by

Affiliation: Brunel University London, University of Sydney

Abstract

There is an increasing need for sustainable sources of omega-3 fatty acids; this challenge can be addressed through large-scale production of eicosapentaenoic acid (EPA) using microalgae. Identification of suitable strains is key in successful process scale-up. However, it is not certain whether conclusions from small-scale systems (i.e. flasks and well plates) can be translated to larger photobioreactors. To examine this issue the productivity and fatty acid composition of eleven different microalgal strains was quantified using both flask and photobioreactor cultures, generating a significant experimental dataset. Results from the flask screening offered relatively poor predictions of performance in photobioreactors, suggesting a need for improved screening tools. Of the species examined, Phaeodactylum tricornutum was found to be the most promising when grown in photobioreactors. To further guide scale-up the effect of environmental conditions (temperature and salinity) on EPA production was examined. It was found that the EPA content was ~5% of the dry biomass and this was approximately constant for the range of temperatures (13–27 °C) and salinities (35–50 g L−1) examined. Finally, detailed nutritional information about the biomass is presented, which can serve as a starting point for its formulation into food products.

Highlights

Eicosapentaenoic and docosahexaenoic acids (EPA and DHA) are essential nutrients for humans due to their vital roles in neurological development and prevention of chronic diseases [1,2,3,4]
Suitable species would have a high eicosapentaenoic acid (EPA) content, the ability to be readily cultivated at scale and have a composition such that they can be readily included in foods
The aims of this work are threefold: i) to quantify the fatty acid composition and biomass productivity at both flask and photo bioreactor scale for a range of species and determine whether results from small-scale systems can be applied at larger scales; (ii) investigate the effects of temperature and salinity changes on the most promising strain with the aim of identifying the range of conditions which could be feasibly used for its large-scale production; and (iii) carry out a detailed nutritional analysis of its biomass

Summary

Introduction

Eicosapentaenoic and docosahexaenoic acids (EPA and DHA) are essential nutrients for humans due to their vital roles in neurological development and prevention of chronic diseases [1,2,3,4]. It has been estimated that the current supply of EPA and DHA from both capture fisheries and aquaculture could meet only 30% of the demand for human consump tion (1.3–1.4 Mt yr− 1) [7,8]. Sustainable strategies are clearly needed to bridge the EPA/DHA supply-demand gap. Heterotrophic processes have the advantage of relatively high productivities, when compared to photoautotrophic processes. They rely on plantbased feedstocks, which may have drawbacks from a sustainability perspective. Development of scalable, cost-effective production processes is the factor limiting the photoautotrophic pro duction of EPA using microalgae. Suitable species would have a high EPA content, the ability to be readily cultivated at scale and have a composition such that they can be readily included in foods

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