Chemical Mutagenesis and Fluorescence-Based High-Throughput Screening for Enhanced Accumulation of Carotenoids in a Model Marine Diatom Phaeodactylum tricornutum.

Zhiqian Yi,Sigurdur Brynjolfsson,Kourosh Salehi-Ashtiani,Yixi Su,Weiqi Fu,Ottar Rolfsson,Andreas Bergmann,Maonian Xu,Saevar Ingthorsson

doi:10.3390/md16080272

Zhiqian Yi, Sigurdur Brynjolfsson + Show 7 more

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https://doi.org/10.3390/md16080272

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Journal: Marine Drugs	Publication Date: Aug 4, 2018
Citations: 36	License type: CC BY 4.0

Affiliation: New York University, University of Iceland

Abstract

Diatoms are a major group of unicellular algae that are rich in lipids and carotenoids. However, sustained research efforts are needed to improve the strain performance for high product yields towards commercialization. In this study, we generated a number of mutants of the model diatom Phaeodactylum tricornutum, a cosmopolitan species that has also been found in Nordic region, using the chemical mutagens ethyl methanesulfonate (EMS) and N-methyl-N′-nitro-N-nitrosoguanidine (NTG). We found that both chlorophyll a and neutral lipids had a significant correlation with carotenoid content and these correlations were better during exponential growth than in the stationary growth phase. Then, we studied P. tricornutum common metabolic pathways and analyzed correlated enzymatic reactions between fucoxanthin synthesis and pigmentation or lipid metabolism through a genome-scale metabolic model. The integration of the computational results with liquid chromatography-mass spectrometry data revealed key compounds underlying the correlative metabolic pathways. Approximately 1000 strains were screened using fluorescence-based high-throughput method and five mutants selected had 33% or higher total carotenoids than the wild type, in which four strains remained stable in the long term and the top mutant exhibited an increase of 69.3% in fucoxanthin content compared to the wild type. The platform described in this study may be applied to the screening of other high performing diatom strains for industrial applications.

Highlights

Diatoms are a major group of unicellular algae, and they play a vital role in global ecosystems [1].They are responsible for nearly half of the primary production and represent the base for marine food webs [1], and various products from marine diatoms such as pigments, polyunsaturated fatty acids (PUFAs) and neutral lipids have attracted extensive attention, as their commercializationMar
Effect of Different Doses of DPA on P. tricornutum Growth been widely applied in mutagenesis experiments to create mutants with higher
DPA can inhibit carotenoid synthesis [12], and the purpose of Herbicides have been widely applied in mutagenesis experiments to create mutants with higher yields of targeted products [12]

Summary

Introduction

Diatoms are a major group of unicellular algae, and they play a vital role in global ecosystems [1].They are responsible for nearly half of the primary production and represent the base for marine food webs [1], and various products from marine diatoms such as pigments, polyunsaturated fatty acids (PUFAs) and neutral lipids (biodiesels) have attracted extensive attention, as their commercializationMar. Diatoms are a major group of unicellular algae, and they play a vital role in global ecosystems [1]. They are responsible for nearly half of the primary production and represent the base for marine food webs [1], and various products from marine diatoms such as pigments, polyunsaturated fatty acids (PUFAs) and neutral lipids (biodiesels) have attracted extensive attention, as their commercialization. Mar. Drugs 2018, 16, 272; doi:10.3390/md16080272 www.mdpi.com/journal/marinedrugs. Mar. Drugs 2018, 16, 272 has been exploited in recent years [1,2,3]. Phaeodactylum tricornutum Bohlin, a model diatom species, has been widely studied due to its ease of cultivation and fully sequenced genome [1].

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