RESUMO
Global market of food enzymes is held by pectinases, mostly sourced from filamentous fungi via submerged fermentation. Given the one-time use nature of enzymes to clarify juices and wines, there is a crucial need to explore alternatives for enzyme immobilization, enabling their reuse in food applications. In this research, an isolated fungal strain (Penicillium crustosum OR889307) was evaluated as a new potential pectinase producer in submerged fermentation. Additionally, the enzyme was immobilized in magnetic core-shell nanostructures for juice clarification. Findings revealed that Penicillium crustosum exhibited enzymatic activities higher than other Penicillium species, and pectinase production was enhanced with lemon peel as a cosubstrate in submerged fermentation. The enzyme production (548.93 U/mL) was optimized by response surface methodology, determining the optimal conditions at 35 °C and pH 6.0. Subsequently, the enzyme was covalently immobilized on synthesized magnetic core-shell nanoparticles. The immobilized enzyme exhibited superior stability at higher temperatures (50 °C) and acidic conditions (pH 4.5). Finally, the immobilized pectinases decreased 30 % the orange juice turbidity and maintained 84 % of the enzymatic activity after five consecutive cycles. In conclusion, Penicillium crustosum is a proven pectinase producer and these enzymes immobilized on functionalized nanoparticles improve the stability and reusability of pectinase for juice clarification.
Assuntos
Nanopartículas , Penicillium , Poligalacturonase/química , Enzimas Imobilizadas/química , Penicillium/metabolismo , Temperatura , Fenômenos Magnéticos , Concentração de Íons de Hidrogênio , Estabilidade EnzimáticaRESUMO
The objective of this research is to compare empirical (pseudo-first and pseudo-second order models) and diffusional models (film diffusion, film-pore-volume diffusion, and film-surface diffusion models) in predicting the adsorption kinetics of chromium(III) on water-washed agro-waste materials (sorghum straw, oats straw, and agave bagasse). Concentration decay curves can be predicted by using either empirical or diffusional kinetic models. However, the film diffusion model seems to be the most appropriated one based on the low reported deviation (0.45-4.09%), and the physical properties (low porosity 0.004-0.007, low surface area 0.6-1.2m(2)g(-1) and low pore volume 0.003-0.004cm(3)g(-1)) of the studied agro-waste materials, which support the idea that intraparticle diffusion may be neglected. Furthermore, the external mass transfer coefficient estimated with the film diffusion model has a physical meaning that helps to explain the diffusion of solutes across the film resistance in agro-waste biosorbents.