Enhancement of pyocyanin production by Pseudomonas aeruginosa via the addition of n-hexane as an oxygen vector

Pseudomonas aeruginosa is capable of producing a wide range of industrially important biotechnological products like pigment, biosurfactants, enzymes, etc. Pyocyanin is a pigment produced by P. aeruginosa and widely used in many industries such as food, agriculture, pharmaceuticals and cosmetics. In order to increase the production of pyocyanin, in this study, the effects of previously untested oxygen vectors on P. aeruginosa OG1 pyocyanin production were studied. The oxygen vectors (n-hexadecane, n-dodecane and n-hexane) were compared in terms of pyocyanin production. All of the oxygen vectors were found to exhibit a stimulatory effect on pyocyanin production and the best result (11.96 mg/L) was obtained with n-hexane. In the next step, pyocyanin production in the presence of n-hexane, was optimized by response surface methodology. In addition to the n-hexane concentration, the optimum size of inoculum and the time of n-hexane addition to the fermentation liquid were investigated. Experimental design and the results were analysed by using Box-Behnken design of Response Surface Methodology (RSM). Accordingly, the optimum size of inoculum was found to be 2.07%, n-hexane concentration was 3.48% and the addition time was 33.93 h and at these optimum values, the amount of pyocyanin increased 2 -fold (21.2 mg/L). According to these results, n-hexane addition as an oxygen carrier could be a useful technique in industrial production of pyocyanin.