Journal of Advances in Microbiology

Introduction: The environmental impact of synthetic dyes have sparked interest in eco-friendly, biodegradable, non-toxic natural colorants. Microbial pigments hold considerable potential for applications in industries such as textile, food, and pharmaceuticals. In this study, a violet pigment producing Streptomyces violaceoruber strain DP6 was isolated, characterized and explored for its use in fabric dyeing.

Materials and Methods: Strain DP6 was isolated from a soil sample collected from Dalhousie, Himachal Pradesh, India. The strain producing a violet pigment was characterized using morphological, cultural, chemotaxonomic, and 16S rRNA sequencing methods. Various physical parameters were studied to obtain the maximum yield of the extracellular pigment. Dyeing potential of the pigment was evaluated on silk and wood fabrics. Further, pigment was purified and characterized.

Results: Optimum pigment production was achieved when DP6 was cultivated for 10 days in ISP5 medium (International Streptomyces Project), at an initial pH of 5.0-5.5, with 2% inoculum, and incubated at 30^oC under shaking conditions (160 rpm). The violet pigment was extracted using ethyl acetate and was found to be highly sensitive to changes in pH and sunlight. The dyeing ability of the violet pigment, produced under optimized conditions was evaluated on wool and silk fabrics. The color yield was observed to be better on wool as compared to silk. Additionally, mutagenicity tests confirmed the non-mutagenic nature of the pigment. Purification and preliminary characterization suggested that the pigment may possess an anthraquinone type structure with a methoxy group.

Conclusions: The study results indicate that the violet pigment from Streptomyces DP6 hold potential to be exploited as a safe dye for use in the textile industry.