Red Light Variation an Effective Alternative to Regulate Biomass and Lipid Profiles in Phaeodactylum tricornutum

Nikunj Sharma,Michael Cheng,Gabriel Fleurent,Hugo Germain,Fatma Meddeb-Mouelhi,Suzanne M Budge,Isabel Desgagné-Penix,Fatima Awwad

doi:10.3390/app10072531

Nikunj Sharma, Michael Cheng + Show 6 more

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https://doi.org/10.3390/app10072531

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Abstract

Marine water diatom Phaeodactylum tricornutum is a photosynthetic organism that is known to respond to the changing light environment and adapt to different temperatures to prevent photoinhibition and maintain its metabolic functions. The objective of the present study was to test whether light shift variations in different growth phases impact the growth and lipid metabolism of P. tricornutum. Thus, we investigated R exposure in different growth phases to find the most effective light shift condition. The results showed that substituting white light (W) by red light (R) under autotrophic conditions, a condition called red shift (RS), increased biomass and lipid content compared to levels found under continuous W or R exposure alone. We observed an increase by 2-fold biomass and 2.3-fold lipid content in RS as compared to W. No significant change was observed in the morphology of lipid droplets, but the fatty acid (FA) composition was altered. Specifically, polyunsaturated FAs were increased, whereas monounsaturated FAs decreased in P. tricornutum grown in RS compared to W control. Therefore, we propose that a light shift during the beginning of the stationary phase is a low-cost cultivation strategy to boost the total biomass and lipids in P. tricornutum.

Highlights

Diatoms Phaeodactylum tricornutum have an important industrial potential for the production of biofuels, nutraceuticals, cosmetics, valuable lipids, and bioactive molecules
P. tricornutum cultured in W is a potentially more valuable source of functional food and animal feed components than P. tricornutum cultivated under R or red with light shift (RS) conditions. These results suggest that the RS condition regulated the fatty acid content in P. tricornutum, lowering monounsaturated fatty acids (MUFA) and increasing Polyunsaturated fatty acids (PUFA)
The present study investigated the impact of red light (R) and a red light shift to full spectrum (RS) on P. tricornutum cell growth, biomass, and lipid production

Summary

Introduction

Diatoms Phaeodactylum tricornutum have an important industrial potential for the production of biofuels, nutraceuticals, cosmetics, valuable lipids, and bioactive molecules. The commercial use of diatom biomass is dependent on input energy and nutrient cost. The large-scale cultivation for a single cell organism at the industrial scale is a challenge considering the variables involved (e.g., energy, nutrients, and contamination issues). Diatoms are known to grow in both benthic and planktonic environments, making them capable of adapting in wide range of light spectra [1,2,3]. Light is the regulating parameter that controls the photosynthetic machinery of diatoms and regulates the range of light-induced physiological responses [3]. The systematic use of light energy affects the cellular metabolism, which is crucial to enhance the quantity and quality of diatom biomass

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