Metabolomics and lipid profile analysis of Coccomyxa melkonianii SCCA 048

Giacomo Fais,Paola Scano,Santina Soru,Pierluigi Caboni,Giacomo Cao,Veronica Malavasi

doi:10.1007/s00792-021-01234-z

Abstract

With an unsupervised GC–MS metabolomics approach, polar metabolite changes of the microalgae Coccomyxa melkonianii SCCA 048 grown under standard conditions for seven weeks were studied. C. melkonianii was sampled at the Rio Irvi River, in the mining site of Montevecchio-Ingurtosu (Sardinia, Italy), which is severely contaminated by heavy metals and shows high concentrations of sulfates. The partial-least-square (PLS) analysis of the GC–MS data indicated that growth of C. melkonianii was characterized by an increase of the levels of threonic acid, myo-inositol, malic acid, and fumaric acid. Furthermore, at the sixth week of exponential phase the lipid fingerprint of C. melkonianii was studied by LC-QTOF-MS. C. melkonianii lipid extract characterized through an iterative MS/MS analysis showed the following percent levels: 61.34 ± 0.60% for triacylglycerols (TAG); 11.55 ± 0.09% for diacylglyceryltrimethyl homoserines (DGTS), 11.34 ± 0.10% for sulfoquinovosyldiacylglycerols (SQDG) and, 5.29 ± 0.04% for lysodiacylglyceryltrimethyl homoserines (LDGTS). Noteworthy, we were able to annotate different fatty acid ester of hydroxyl fatty acid, such as FAHFA (18:1_20:3), FAHFA (18:2_20:4), FAHFA (18:0_20:2), and FAHFA (18:1_18:0), with relevant biological activity. These approaches can be useful to study the biochemistry of this extremophile algae in the view of its potential exploitation in the phycoremediation of polluted mining areas.

Highlights

In response to the search for more biofuel sources, strains of the genus Coccomyxa have been studied for their ability to produce lipids and, given the high concentration of polyunsaturated ω-3 and ω-6 fatty acids, some strains may cover an important role in the food and feed industry (Jeong et al 2011)
The aim of this study was to explore the metabolic profiles of C. melkonianii Sardinian Culture Collection of Algae (SCCA) 048 grown under standard conditions, and to obtain basic lipidome profile information for the potential use of this microalga in the bioremediation of the drainage waters of the Rio Irvi insisting in the mining area of Ingurtosu
As a first step towards the metabolic profiling of C. melkonianii SCCA 048, we monitored the growth of the microalgal strain along seven weeks

Summary

Introduction

Trebouxiophyceae show different phenotypic, physiologic, and genetic characteristics determining their ability to survive in these environments (Assunção et al 2017; Cannell 1993) Belonging to this class, Coccomyxa spp. with more than 60 described species (Guiry et al 2020) are morphological characterized by a parietal chloroplast without a pyrenoid and a thin three-layered cell wall, and by the lack of flagellum (Brunner and Honegger 1981; Darienko et al 2015; Malavasi et al 2016). The extremophile microalga C. melkioananii SCCA 048 was sampled in acidic mine drainage waters severely contaminated by heavy metals This mining site of Montevecchio-Ingurtosu (Sardinia, Italy) is characterized by minerals such as galena (PbS2) containing appreciable levels of silver, sphalerite ((Zn, Fe)S) containing Cd, Ga, In, and the oxide mineral goethite (α-FeO(OH)). This site is rich in pollutants, with levels of Z n2+ at 956 mg/L, Fe2+ at 227 mg/L, and sulfates at 3697 mg/L, released into the river by oxidation reactions involving the sulfide minerals still present in the ore bodies after flooding of galleries (De Giudici et al 2018)

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