Published in Scientific Papers. Series "Journal of Young Scientist", Vol. 10
Written by Ștefan BĂRBULESCU, Iana Andreea GHIMIȘI (DRAGOMIR), Marcela CHIRU, Denis NENCIU, Daniela VĂCĂROAIA, Beatrice SANDU
The filamentous fungi are among the most dominant phylum in the nature and great due to their significant contributions to biotechnological applications for the welfare of human being. Filamentous fungi are widely distributed in diverse ecological niches and produce extraordinary range of secondary metabolites. The pigments from filamentous fungi were used as food colorants, natural dyes in textile industry, cosmetics and pharmaceutical industry. Natural pigments from filamentous fungi serve as a green alternative to synthetic dyes in food colorants, cosmetics and are biodegradable in nature. Filamentous ascomycetes fungi are known to produce an extraordinary range of colours. There is a wide selection of non-pathogenic strains of filamentous fungi that are non-toxin producers and can be used as potential sources of natural food colorants with improved functionality. The ability of these fungi to grow on residuals of different complexity (e.g., starch-based, lignocellulose-based residuals) is well-documented, showing versatility regarding different processes that can be built around the filamentous fungi. Unlike the use of pigments from vegetables and fruits, the cultivation of ascomycetes does not compete with agricultural land for food production, and therefore, the synthesis of pigments is faster due to time-efficient and simple fermentation processes. The fermentation processes generate high yields of biomass together with value-added products such as pigments, organic acids and alcohols. Interest in food-grade pigments is because of the pigments’ ability to enhance the products’ natural color in order to indicate freshness, appearance, safety, and sometimes even to add a novel sensory aspect to attract consumers. A few strains of ascomycetes filamentous fungi being considered as potential pigment producers include, some strains of Talaromyces (e.g., T. purpurogenus and T. atroroseus producing red pigments), Cordyceps unilateralis (deep blood red pigment), Herpotrichia rhodosticta (orange), Curvularia lunata and several species of Drechslera (many different pigments). Strains of these species are promising because they are non-mycotoxigenic and non-pathogenic to humans. Nevertheless, the individual mycotoxin profiles of these strains remain to be explored. Some other pigment producing fungi for their use in the production of potential food colorants are species of Eurotium and Fusarium oxysporum (yellow and red pigments, respectively), Fusarium fujikuroi (red and orange pigments) and strains of Penicillium such as P. citrinum, P. islandicum, P. aculeatum and P. pinophilum. However, several species of Penicillium are able to produce known toxic metabolites and Eurotium spp. and F. oxysporum have been shown to produce mycotoxins as well. The potential production of mycotoxins is a major problem which limits the commercial application of these strains of fungi. This problem, together with the increasing demand for natural coloring alternatives from both customers and regulators, has triggered investigations and screens for other potential pigment-producing genera of fungi. In this paper we present the isolation from the environment of some new strains of filamentous fungi on PDA agar culture medium, their cultivation in laboratory conditions for the production of pigments in a liquid medium in a submerged system in incubators with orbital agitation – rotary shaker. We also present the optimization of pigment production on different liquid culture media. The subsequent studies will aim the taxonomic identification of each newly isolated fungal strain, the production of mycotoxins, which could prohibit the use of these fungi as potential producers of useful pigments in the food industry, and last but not least, the isolation and biochemical identification of the molecular structure of pigments produced by these fungi.
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