Electrochromic Properties and Electrochemical Behavior of Marennine, a Bioactive Blue-Green Pigment Produced by the Marine Diatom Haslea ostrearia.

Nellie Francezon,Charles Cougnon,Pamela Pasetto,Boris Jacquette,Jens Dittmer,Mickaël Herbaut,Jean-Luc Mouget,Jean-François Bardeau,Jean-Bernard Pouvreau,William Bélanger,Réjean Tremblay

doi:10.3390/md19040231

Abstract

Marennine has long been known as the unique peculiar pigment responsible for the natural greening of oysters. It is specifically produced by the marine diatom Haslea ostrearia and it is a natural blue molecule indeed promising for food industry because of the rarity of such non-toxic, blue-colored pigments. In the search for its still not defined molecular structure, investigation of the color changes with the redox state has been carried out combining different approaches. Reducing and oxidizing chemicals have been added to purified marennine solutions and a stable blue-green color has been confirmed for the oxidized state, while a yellow color corresponded to the reduced unstable state. Raman spectroscopy has been used to monitor changes in the Raman spectra corresponding to the different colored states, and cyclic voltammetry has allowed the detection of a redox system in which protons and electrons are exchanged. These findings show that marennine is a suitable stable blue pigment for use in food applications and help in the elucidation of the chromophore structure.

Highlights

Marennine has long been known as the unique peculiar pigment responsible for the natural greening of oysters [1], produced by the marine diatom Haslea ostrearia (Gaillon) Simonsen (e.g., [2])
Extracellular Marennine (EMn) was obtained using two purification procedures associated with two different size cultures: in small-scale marennine production (20 L), the extracellular marennine (EMn) in the supernatant was purified by precipitation using chemicals, and in scale-up production (100 L) by mechanical purification using ultrafiltration
Recent research on marennine chemical structure has led to the investigation of its electrochemical behavior

Summary

Introduction

Marennine has long been known as the unique peculiar pigment responsible for the natural greening of oysters [1], produced by the marine diatom Haslea ostrearia (Gaillon) Simonsen (e.g., [2]) This microalga was first named Vibrio ostrearius [3], renamed Navicula ostrearia by Bory [4] when he defined a new genus Navicula to encompass taxa for microorganisms that have a cell shape resembling a weaver’s shuttle, and Haslea ostrearia when Simonsen [5] proposed a new genus Haslea to include all pennate, lanceolate diatom species characterized by specific morphological features of their frustule, H. ostrearia being the generitype (see Poulin et al, 2019 [6]). Significant strain- and species-dependent activities against Vibrio bacteria have been evidenced [15], with possible application in aquaculture as an anti-pathogen agent [16]

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Conclusion