Dimensionamento de biorreator para produção da vitamina B12 por Pseudomonas denitrificans

Abstract

Vitamin B12 is an essential micronutrient for human metabolism, acting in DNA synthesis, red blood cell formation and maintenance of the nervous system. People with difficulty ingesting and/or absorbing vitamin B12 require vitamin B12 supplementation, which generates an international market of approximately US$194.3 million. Since its natural production is restricted to certain microorganisms, its industrial-scale production depends on highly controlled fermentation processes. In this context, the study proposed the design of a stirred tank bioreactor (STR) aimed at the microbiological production of vitamin B12 by Pseudomonas denitrificans, which is established as the microorganism with the best production efficiency. Fundamental process parameters were collected from scientific articles in a benchtop bioreactor for subsequent design of an industrial bioreactor using Excel software. The following parameters were analyzed as fundamental parameters: volumetric oxygen transfer coefficient (kLa), impeller tip speed (Vtip), aeration rate (Na), Reynolds number (NRe) and mixing time (Tm), which directly impact mass transfer efficiency, flow regime and degree of shear applied to the cells. The results indicated a bioreactor with a useful volume of 5.05 m³ and liquid height corresponding to 57.4% of the total height of the equipment, ensuring operational efficiency. The oxygen transfer rate of 73.49 h⁻¹ and the shear rate of 615 s⁻¹ were compatible with the physiological requirements of Pseudomonas denitrificans, promoting an environment conducive to the production of vitamin B12. In addition to the calculations, a three-dimensional model of the bioreactor was developed in SolidWorks [trade mark] software, incorporating all the necessary elements, such as a lid with connections, air inlet, sensors, heat exchange jacket and agitation system with impellers sized according to the process requirements, showing that the final project is technically viable, with application on an industrial scale, contributing to the development of efficient processes in the production of B12.