Abstract:

Microbial pigments have gained significant scientific attention due to their biodegradability, eco‑friendliness, and wide range of biological activities. This study investigated the production, characterization, and optimization of pyocyanin from Pseudomonas aeruginosa isolated from soil samples. Soil samples were collected from different locations and processed using serial dilution and standard microbiological techniques. Pigment‑producing bacterial isolates were identified through morphological, biochemical, and molecular characterization. Pyocyanin production was achieved by submerged fermentation, followed by extraction using chloroform. Characterization of the extracted pigment was performed using Gas Chromatography–Mass Spectrometry (GC‑MS) and Fourier Transform Infrared Spectroscopy (FTIR). Optimization of pyocyanin production was carried out using the One‑Factor‑At‑a‑Time (OFAT) approach by evaluating the effects of culture media, pH, temperature, and incubation time. Molecular analysis confirmed isolate D3 was Pseudomonas aeruginosa strain NBRC 126891 with 96% similarity. GC‑MS analysis revealed Phenol, 2,4‑bis(1,1‑dimethylethyl) as the predominant compound, accounting for 79.66% of the peak area. FTIR analysis showed major absorption peaks at 3291 cm⁻¹ and 1630 cm⁻¹ corresponding to O–H and C–H stretching vibrations, respectively. Optimization studies showed that King’s A medium, pH 7.0, a temperature of 35°C, and an incubation period of 48 hours were the optimal conditions for pyocyanin productionkings A with a yield of 4.2, pH of 7.0 with 4.3, temperature of 35 °C with 4.5 and incubation time of 48hrs with 4.4µg/ml. The study demonstrates that Pseudomonas aeruginosa isolated from soil can serve as an effective source of pyocyanin for potential pharmaceutical and industrial applications.