Mireille Fouillaud

Filamentous fungi are large-scale producers of pigments and colorants for the food industry

With globalization in the research trends, healthier life styles, and the growing market for the natural food colorants in the economically fast-growing countries all over the world, filamentous fungi are being investigated as readily available sources of chemically diverse colorants. With two selected examples, polyketide-Monascus-like pigments from the new fungal production strains, and the promising and yet unexplored hydroxy-anthraquinoid colorants, the present review highlights exciting recent findings, which may pave the way for alternative and/or additional biotechnological processes for the industrial production of natural food colorants of improved functionality. As an additional aspect, marine fungi are discussed as potential sources of novel pigments of numerous color hues and atypical chemical structures.

Natural hydroxyanthraquinoid pigments as potent food grade colorants: an overview

Natural pigments and colorants are widely used in the world in many industries such as textile dying, food processing or cosmetic manufacturing. Among the natural products of interest are various compounds belonging to carotenoids, anthocyanins, chlorophylls, melanins, betalains… The review emphasizes pigments with anthraquinoid skeleton and gives an overview on hydroxyanthraquinoids described in Nature, the first one ever published. Trends in consumption, production and regulation of natural food grade colorants are given, in the current global market. The second part focuses on the description of the chemical structures of the main anthraquinoid colouring compounds, their properties and their biosynthetic pathways. Main natural sources of such pigments are summarized, followed by discussion about toxicity and carcinogenicity observed in some cases. As a conclusion, current industrial applications of natural hydroxyanthraquinoids are described with two examples, carminic acid from an insect and Arpink red™ from a filamentous fungus.Graphical abstract

Anthraquinones and Derivatives from Marine-Derived Fungi: Structural Diversity and Selected Biological Activities.

Anthraquinones and their derivatives constitute a large group of quinoid compounds with about 700 molecules described. They are widespread in fungi and their chemical diversity and biological activities recently attracted attention of industries in such fields as pharmaceuticals, clothes dyeing, and food colorants. Their positive and/or negative effect(s) due to the 9,10-anthracenedione structure and its substituents are still not clearly understood and their potential roles or effects on human health are today strongly discussed among scientists. As marine microorganisms recently appeared as producers of an astonishing variety of structurally unique secondary metabolites, they may represent a promising resource for identifying new candidates for therapeutic drugs or daily additives. Within this review, we investigate the present knowledge about the anthraquinones and derivatives listed to date from marine-derived filamentous fungi′s productions. This overview highlights the molecules which have been identified in microorganisms for the first time. The structures and colors of the anthraquinoid compounds come along with the known roles of some molecules in the life of the organisms. Some specific biological activities are also described. This may help to open doors towards innovative natural substances.

Production and New Extraction Method of Polyketide Red Pigments Produced by Ascomycetous Fungi from Terrestrial and Marine Habitats

The use of ascomycetous fungi as pigment producers opens the way to an alternative to synthetic dyes, especially in the red-dye industries, which have very few natural pigment alternatives. The present paper aimed to bio-prospect and screen out 15 selected ascomycetous fungal strains, originating from terrestrial and marine habitats belonging to seven different genera (Penicillium, Talaromyces, Fusarium, Aspergillus, Trichoderma, Dreschlera, and Paecilomyces). We identified four strains, Penicillium purpurogenum rubisclerotium, Fusarium oxysporum, marine strains identified as Talaromyces spp., and Trichoderma atroviride, as potential red pigment producers. The extraction of the pigments is a crucial step, whereby the qualitative and quantitative compositions of each fungal extract need to be respected for reliable identification, as well as preserving bioactivity. Furthermore, there is a growing demand for more sustainable and cost-effective extraction methods. Therefore, a pressurized liquid extraction technique was carried out in this study, allowing a greener and faster extraction step of the pigments, while preserving their chemical structures and bioactivities in comparison to conventional extraction processes. The protocol was illustrated with the production of pigment extracts from P. purpurogenum rubisclerotium and Talaromyces spp. Extracts were analyzed by high-performance liquid-chromatography combined with photodiode array-detection (HPLC-DAD) and high-resolution mass spectrometry (UHPLC-HRMS). The more promising strain was the isolate Talaromyces spp. of marine origin. The main polyketide pigment produced by this strain has been characterized as N-threoninerubropunctamine, a non-toxic red Monascus-like azaphilone pigment.

First isolation of Brevibacterium sp. pigments in the rind of an industrial red-smear-ripened soft cheese

The smear-ripened soft cheeses are characterised by a surface orange-red-brown colour, which has a microbial origin. For a long time, this colouration was mainly imputed to Brevibacterium linens. However, the latest published works, based on molecular biology, have shown a minor role for this bacterium. This study shows the results obtained with an industrial cheese named Vieux-Pane, which is characterised by the presence of carotenoids from Brevibacterium linens group at its surface. This demonstrates that, under certain conditions, the Brevibacterium linens group (Brevibacterium linens and Brevibacterium aurantiacum sp. nov.) is able to produce pigments and to colour cheeses effectively.

Biodiversity of Pigmented Fungi Isolated from Marine Environment in La Réunion Island, Indian Ocean: New Resources for Colored Metabolites

Marine ecosystems cover about 70% of the planet surface and are still an underexploited source of useful metabolites. Among microbes, filamentous fungi are captivating organisms used for the production of many chemical classes of secondary metabolites bound to be used in various fields of industrial application. The present study was focused on the collection, isolation, screening and genotyping of pigmented filamentous fungi isolated from tropical marine environments around La Réunion Island, Indian Ocean. About 150 micromycetes were revived and isolated from 14 marine samples (sediments, living corals, coral rubble, sea water and hard substrates) collected in four different locations. Forty-two colored fungal isolates belonging to 16 families, 25 genera and 31 species were further studied depending on their ability to produce pigments and thus subjected to molecular identification. From gene sequence analysis, the most frequently identified colored fungi belong to the widespread Penicillium, Talaromyces and Aspergillus genera in the family Trichocomaceae (11 species), then followed by the family Hypocreaceae (three species). This study demonstrates that marine biotopes in La Réunion Island, Indian Ocean, from coral reefs to underwater slopes of this volcanic island, shelter numerous species of micromycetes, from common or uncommon genera. This unstudied biodiversity comes along with the ability for some fungal marine inhabitants, to produce a range of pigments and hues.