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The diffusion ofproteins in polymer matrices is an important step in the adsorptive and chromatographic processes used for protein purification, as it is often ratelimiting. Methods f o r the estimation of the intraparticle diffusivity in polymer gels have been developed and were applied to the diffusion of seven model proteins in agarose particles. The intraparticle diffusivity was not affected by particle diameter.A correlation based on the restricted diffusion model of Ogston et al. (1973) and Cukier (1984) has been proposed. This correlation allows the estimation of protein diffsivity in these matrices based on the molecular weight of the protein and the polymer concentration.

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The fluorescence of a batch culture of Pseudomonas putida grown on phenol was investigated. A linear relationship was found between cell concentration and culture fluorescence during in the early exponential growth phase.Accumulation of a metabolite in the culture broth affects fluorescence by NADH consumption and inner filter effects. The fluorescence is also affected by changes in the metabolic activity of the cells. These effects during the course of the fermentation are discussed.