Production and Characterization of Novel Pigmented Secondary Metabolites by Endophytic Pseudomonas sp. Strain Anjali MT-02 (PQ098594) Isolated from Mentha piperita.

The growing demand for natural pigment sources is driven by increasing concerns about environmental preservation and human health. Microbial pigments, with their higher bioactivity, offer a range of beneficial properties such as antimicrobial, antitumor, and antiallergic activities, making them valuable for pharmaceutical applications. In this study, pigment-producing metabolites from endophytic bacteria were isolated from Mentha piperita leaves using enrichment culture techniques. The isolated bacterial strain was identified as Pseudomonas sp. Anjali MT-02 (Accession number PQ098594). The production of pigments was optimized through response surface methodology, with factors such as pH, temperature, incubation time, and inoculum size being varied. The highest pigment production occurred when the bacteria were cultured at 35 °C for 96 h at pH 6.4, with an inoculum size of 3.3 mL/100 mL. UV-Visible spectra revealed a maximum absorption at 636 nm. Additionally, the pigments demonstrated excellent dyeing potential on cotton fabric, indicating their suitability for various applications. Also, PSM showed almost three times more inhibition zone against both gram positive and gram negative bacterial strains. Also, PSM showed non-toxic to rat fibroblast cells. These results suggested that PSM have potential to use for biomedical application. This research highlights the potential of utilizing endophytic bacteria for sustainable, high-value pigment production, with significant implications for microbial biotechnology and natural product synthesis.