3.2 Screening for colorant production
Based on the visual evaluation of the colorants produced by fungi in the culture medium, eight isolates stood out for producing the most intense colorants and were submitted to submerged bioprocesses, extraction, and evaluation of the solubility of the colorant. In Fig. 1, more colorful fractions were obtained from the extraction with different solvents from the mycelial mass, and the fraction of the culture filtrate, which has a greater polarity, showed the most intense extracellular colorants.
The isolates Penicillium sp. P3SO332, Clonostachys sp. P2SO329 and Penicillium sp. P3SO224 were selected to evaluate the absorptivity of the colored extracts, which was obtained in the UV/VIS region. The colored fractions were scanned at 400–700 nm to determine the maximum absorption wavelength (λmax) in ethyl acetate. Scanning spectrophotometry showed that the three colorants evaluated have a maximum absorbance around 400 nm.
The four fungi highlighted in the production of colorants (Penicillium sp. P3SO332,Clonostachys sp. P2SO329,Penicillium sp. P3SO224,Monascus sp. C02172R) were subjected to DNA sequencing of the targets ITS1-5.8S rDNA-ITS2 to confirm their genus and possible DNA identification. The phylogenetic tree constructed is shown in Fig. 2. The isolate Penicilliumsp. P3SO332 was identified as Penicillium gravinicasei P3SO332 (99% accession: MG600581.1). Clonostachys sp. P2SO329 was identified as Clonostachys rosea P2SO329 (99% accession: MN452057.1). Penicillium sp. P3SO224 was identified asPenicillium sclerotiorum P3SO224 (99% accession: MN639705.1).Monascus sp. C02172R was identified as Monascus purpureusC02172R (99% accession: MT355839.1). The nucleotide sequences obtained after amplification and sequencing were submitted to NCBI GenBank and the accession numbers OP563023, OP563026, OP563024 and OP563023, respectively, were obtained.