Optimization of
growth parameters and pigment production in Streptomyces. sp. VITGV38 and analysis
of its secondary metabolite properties
Soniyagandhi Elumalai and Christopher Godwin John
Res. J. Biotech.; Vol. 20(12); 184-191;
doi: https://doi.org/10.25303/2012rjbt1840191; (2025)
Abstract
Colours are an integral part of daily life, with synthetic dyes widely used in various
industries. However, concerns over their toxicity have driven the search for safer,
eco-friendly alternatives. Microbial pigments have emerged as a sustainable and
biodegradable substitute, with increasing global demand for natural colourants.
This study focused on optimizing pigment production and evaluating the antimicrobial
activity of secondary metabolites from Streptomyces sp. VITGV38 (MCC 4869). Among
different tested media, starch casein agar supported the highest pigment yield whereas
Luria-Bertani agar showed the least. Optimal growth and pigment production were
achieved with 2% NaCl, pH 8–8.5 and a 21-day incubation period. Nutritional optimization
using 2% maltose and potassium nitrate as carbon and nitrogen sources respectively,
along with amino acids like tyrosine, threonine and tryptophan, further enhanced
bioactive metabolite production.
Ethyl acetate was used to extract the crude pigment. The dark brown extract demonstrated
significant antibacterial activity against four pathogens via the agar well diffusion
method. The highest inhibition was observed against Staphylococcus aureus (25 mm)
followed by Pseudomonas aeruginosa (23 mm), Bacillus subtilis (21 mm) and Escherichia
coli (20 mm), highlighting the potential of Streptomyces pigments as promising natural
bioactive agents.
