1. INTRODUCTION
A colorant is any substance added to a product for the purpose of
changing its color, enhancing the existing color or restoring lost
color. Natural colors are pigments made by living organisms (plants,
lichens, algae, insects, bacteria and fungi) [1–3]. There is low
consumer interest for the use of the synthetic colorants due to the fact
that they are toxic to human health (mutagenic and carcinogenic
potential) [4,5]. The current legislation of the European Union, the
United States, Brazil, Norway and Sweden also limits the use of
synthetic colorants as food additives, and the process used to produce
synthetic colorants is toxic to the environment [6,7].
However, natural colorants extracted from plants have a drawback, i.e.,
they depend on seasonal availability[8]. As a potential bioprocess
for the new bioindustry of colorants, the production of colorants using
microbial fermentation is rising, since it is possible to reduce
production costs by choosing the best growing conditions; in addition,
unlike plants microorganisms do not depend on climatic conditions
[9–11]. As well as these advantages, many fungi-based colorants
have important biological properties, such as antimicrobial,
antioxidant, immunosuppressive, antiviral, anticancer and
cholesterol-lowering properties, which make them important compounds for
numerous industries. As a result, there is growing worldwide interest
for the use of natural colorants[12–14] .
Studies have shown the potential of Amazonian fungi for colorant
production. One study that can be highlighted isolated fungi-producing
pigments [15] and obtained fractions with colors ranging from yellow
to red. Penicillium sclerotiorum 2AV2 produced intensely colored
pigments and the pigment was identified as sclerotiorin, which has
specific biological activities such as the inhibition of aldose
reductase enzymes, lipases, integrins and proteases of the human
immunodeficiency virus HIV-1[16]. Teixeira et al. [17] evaluated
the antibacterial activity and toxicity of organic extracts. The authors
identified antimicrobial activity and lack of toxic action of the
colorants produced by strains of the genus Aspergillus andPenicillium.
The Amazon Rainforest contains a rich diversity of microorganisms.
Despite the richness of biological diversity in the Amazon, few works
have been dedicated to researching fungal colorants. Therefore, the
present study aimed to identify fungal isolates with the potential for
production of colorants.