Biosynthesis of Pyocyanin Pigment by Pseudomonas aeruginosa Using Various Agro-Residues as Substrate

Abstract

Pyocyanin is a natural blue-green pigment produced by various strains of Pseudomonas aeruginosa with diverse applications in medicine, agriculture, and industries. Large scale production of pyocyanin remained challenging due to high production costs, low yield and high cost of synthetic fermentation medium. The aim of this study was to produce pyocyanin pigment via solid state fermentation by Pseudomonas aeruginosa using various agro-industrial residues. Proximate composition of the substates used for the production i.e. wheat bran, corn cob, corn bran, rice bran, sugarcane bargasse and peptone water was carried-out. The isolate used in this study was collected from the Main Teaching Laboratory, Department of Microbiology A.B.U Zaria. The isolate was confirmed by conventional cultural and biochemical tests. Pyocyanin production was conducted through solid-state fermentation, utilizing the substrate, mineral salt solution, and the inoculum. Proximate analysis showed various amount of protein in all the substrates in the following order: wheat bran (17.73%), corn bran (10.53%), sugarcane bagasse (5.84%), rice bran (7.71%) and corn cob (4.28%), respectively. Biochemical tests and the green pigmentation produced by the isolate in nutrient agar confirmed the identity of the isolate. The amount of pyocyanin produced are 10.243 μg ml⁻¹ for wheat bran, 14.084μg ml⁻¹ sugarcane bagasse, 10.920 μg ml⁻¹ for corn bran, 9.560 μg ml⁻¹ for rice bran, 0.00 μg ml⁻¹ for corn cob and 10.072μg ml⁻¹ for peptone water, respectively. These findings revealed that all the studied substrate supported pyocyanin production with the exception of corn cob, and the highest support was observed in sugarcane bagasse. Therefore, these substrates could be used as potential substrate for a large-scale industrial production of pyocyanin under optimized conditions.