Bioprospecting of Talaromyces ruber pigments for antimicrobials

Abstract

Introduction and Aim: Metabolic flexibility of fungi is unique among organisms. Fungi can produce various pigments of industrial importance. Potential of Talaromyces ruber for beneficial pigments needs to be explored. Hence, the present study aims at the detection of pigments from T. ruber and determining their antimicrobial properties.   Materials and Methods: A soil isolate of T. ruber was tested for pigment production. Cellular and secretory pigments were extracted. They were separated by thin-layer chromatography (TLC) and detected by UV-Visible spectrophotometry. The antibacterial activities of crude pigments were tested by disc diffusion method. The antifungal activity was detected by disc diffusion method, conidial germination inhibition assay and bioautography methods.   Results: The results showed that cellular metabolites yielded seven pigment fractions and secretory metabolites yielded five different pigment fractions in TLC. In UV-Visible spectrometry, the absorption range of visible light with 370 to 412 nm detected yellow pigments and absorption of 500 to 520 nm detected red pigments. Crude cellular and secretory pigment fractions showed inhibition activity only on Bacillus subtilis. The antifungal activity of both crude cellular and secretory pigments was observed against Candida albicans and Cryptococcus sp. The secretory crude pigment showed conidial germination inhibition only against Alternaria tenuissima. In bioautography, the cellular and secretory crude pigments showed an inhibition zone for Cladosporium oxysporum. Additionally, secretory crude pigment showed similar activity against Curvularia lunata. Interestingly, the variations in the antifungals between cellular and secretory pigment fractions are also evident. Production of antimicrobial compounds from T. ruber was established after the detection of pigment fractions.   Conclusion: Potential of T. ruber to produce yellow and red pigments was realized. Antimicrobial pigments from T. ruber were detected providing scope to develop for industrial scale. These pigments may be used in pharmaceutical and nutritional industries.