Síntese, modelagem, simulação e análise técnica-econômica de uma planta de produção de biocatalisadores heterogêneos para obtenção de fruto-oligossacarídeos

Abstract

Fructooligosaccharides (FOS) are low-calorie prebiotic sugars that promote a series of benefits to human and animal health and nutrition. They can be produced by the occurrence of transfructosylation in sucrose molecules, catalyzed by fructosyltransferase enzymes (FTase E.C.2.4.1.9) adhered to microbial cells. The immobilization of cells on support materials allows to obtain robust heterogeneous biocatalysts with high activity, specificity and selectivity, while the cross-linking of immobilized cells allows them to be produced with greater operational stability, enabling their application in continuous reaction systems. Polyurethane sponges (EPU) are suitable supports for cell immobilization as they have thermal and mechanical stability, in addition to the size and distribution of pores that enable gaseous and substrate diffusion, essential for microbial growth. One of the main challenges encountered when implementing a biocatalyst production plant, aiming to synthesize FOS in Brazil, is related to its production stage. Therefore, the use of immobilized microbial cells, with enzymatic activity, can become a feasible alternative for industrial application. In this context, it is proposed to carry out the synthesis, modeling, simulation, technical-economic analysis (TEA) and sensitivity of a heterogeneous biocatalyst production plant aiming at the synthesis of FOS from Aspergillus oryzae IPT-301 cells, with activity of transfructosylation, immobilized in EPU cubes. The simulations were carried out in the EMSO software for scenarios involving cells immobilized and cross-linked in EPU (Scenario A) and only for cells immobilized in EPU (Scenario B) through the processing of 4.5 kg/h of VHP (Very High Polarization) sucrose. used as substrate. In scenario A, 2.776 kg/h of the heterogeneous biocatalyst were obtained with an energy expenditure of 6.298 kW, while in scenario B 2.789 kg/h of the biocatalyst were produced with an energy expenditure of 6.167 kW. For both scenarios, a productivity of 2.812 kg/m3.h of the heterogeneous biocatalyst was obtained. The processes presented high production costs, resulting in a minimum sales price higher than the proposed value of 420 US$/kg for scenario A (437,285 US$/kg) and 210 US$/kg for scenario B (376,296 US$ /kg). Furthermore, both scenarios had a negative NPV, making the processes unfeasible from an economic point of view. In sensitivity analyses, it was found that scenario B requires a large change in the sales price to be economically viable. However, small changes in the variables of scenario A make it possible to make the process viable, since the cells immobilized and cross-linked in EPU have greater enzymatic activity and, therefore, have a positive impact on the increase in FOS production.