The production of sorbitol by permeabilized and immobilized cells of Z. mobilis in sucrose

The production of sorbitol by permeabilized and immobilized cells of Zymomonas mobilis in Luffa cylindrica was investigated in sucrose medium. A full 2³ factorial design was used to verify the influence of each factor and its interactions. The cell permeabilization showed a significant and negative effect upon the production of sorbitol, while the time of cultivation and the immobilization process were significant and positive. The results demonstrated that the cell immobilization and the time of cultivation of 36 h presented higher production of sorbitol.

Foi investigado a produção de sorbitol em meio de sacarose por células de Z. mobilis permeabilizadas e imobilizadas em Luffa cylindrica. Este trabalho avaliou o efeito da permeabilização de células de Z. mobilis tratadas com cetilmetilamoniobrometo e imobilizadas em Luffa cylindrinca. Um planejamento fatorial completo 2³ foi utilizado para verificar a influência dos fatores e suas interações. A permeabilização da célula mostrou um efeito significante e negativo sobre a produção de sorbitol, enquanto o tempo de cultivo e o processo de imobilização foram significantes e positivos. Os resultados mostraram que a imobilização das células e o tempo de cultivo de 36h forneceram concentração mais elevadas de sorbitol.

Difusäo do cloreto de sódio no processo de maturaçäo de queijos: modelagem matemática com o emprego do método de elementos finitos / The sodium chlorid diffusion during cheese ripening: matematical model applyng the finite element method

Solute (sodium chloride) transference through a three-dimensional matrix, during cheese ripening, was studied applying the finite element method (MEF). The variational formulation 9Galerkin) of the differential problem (diffusion model) had as the theoretical basis Fick's second law. The methods for time integration were developed according to Crank-Nicolson (central difference), and modified Euler (backward difference), which presented unconditional stability. The computational program proved to be versatile in solving sampling situations in realistic condition nd can be used in complex geometry. The application of numeric method (MEF) withmodified-Euler scheme in the simulation of diffusion of sodium chloride in the ripening, showed to be close to the values published in specialized literature