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Pseudomonas aeruginosa metabolizes pyocyanin, a redox molecule related to diverse biological activities. Culture conditions for the production of pyocyanin in a defined medium were optimized using a statistical design and response surface methodology. The obtained conditions were replicated using as substrate an alkaline residual liquid of cooked maize and its by-products. The untreated effluent (raw nejayote, RN) was processed to obtain a fraction without insoluble solids (clarified fraction, CL), then separated by a 30 kDa membrane where two fractions, namely, retentate (RE) and filtered (FI), were obtained. Optimal conditions in the defined medium were 29.6 °C, 223.7 rpm and pH = 6.92, which produced 2.21 μg mL−1 of pyocyanin, and by using the wastewater, it was possible to obtain 3.25 μg mL−1 of pyocyanin in the retentate fraction at 40 h. The retentate fraction presented the highest concentration of total solids related to the maximum concentration of pyocyanin (PYO) obtained. The pyocyanin redox behavior was analyzed using electrochemical techniques. In this way, valorization of lime-cooked maize wastewater (nejayote) used as a substrate was demonstrated in the production of a value-added compound, such as pyocyanin, a redox metabolite of Pseudomonas aeruginosa NEJ01R.

By-products of biodiesel production, such as crude glycerol, require options for their valorization, which allow obtaining high value products with application in several areas. To achieve this, the use of crude glycerol for the production of pyocyanin was analyzed using three strains of Pseudomonas aeruginosa, to increase the concentration of metabolite and compare it with that produced using lysogeny broth (LB medium). The effect was dependent on the strain used, shown positively by only two strains. The physiology of P. aeruginosa was analyzed using glycerol as the sole carbon source and the complete substrate for pyocyanin biosynthesis. The extracted compound was identified by UPLC-MS and characterized by electrochemical techniques. The voltamperometric response of the pyocyanin allowed analyzing its ability to participate in redox behaviour and the mechanisms on the electrode surface, which could be associated with adsorption processes. This study shows the potential of the strains used to obtain redox metabolites of high interest with application in bioelectrochemical systems. In ORIGINAL RESEARCH