In this study, a continuous protein recovery process using a Liquid–Solid Circulating Fluidized Bed (LSCFB) ion exchange system is described and a model with known kinetics has been developed. Experiments and computer simulations using Matlab™ are conducted at different operating conditions. The effects of hydro‐dynamic parameters and kinetic parameters on the performance of the LSCFB ion exchange system are discussed. The model is shown to be applicable for the design of LSCFB ion exchange systems for protein recovery.

No abstract

The IGFI receptor promotes malignant progression and has been recognized as a target for cancer therapy. Clinical trials with anti-IGFIR antibodies provided evidence of therapeutic efficacy but exposed limitations due in part to effects on, and the compensatory function of, the insulin receptor system. Here, we report on the production, characterization, and biologic activity of a novel, IGF-targeting protein (the IGF-Trap) comprising a soluble form of hIGFIR and the Fc portion of hIgG 1 . The IGF-Trap has a high affinity for hIGFI and hIGFII but low affinity for insulin, as revealed by surface plasmon resonance. It efficiently blocked IGFIR signaling in several carcinoma cell types and inhibited tumor cell proliferation, migration, and invasion in vitro. In vivo, the IGF-Trap showed favorable pharmacokinetic properties and could suppress the growth of established breast carcinoma tumors when administered therapeutically into tumor-bearing mice, improving disease-free survival. Moreover, IGF-Trap treatment markedly reduced experimental liver metastasis of colon and lung carcinoma cells, increasing tumor cell apoptosis and reducing angiogenesis. Finally, when compared with an anti-IGFIR antibody or IGF-binding protein-1 that were used at similar or higher concentrations, the IGF-Trap showed superior therapeutic efficacy to both inhibitors. Taken together, we have developed a targeted therapeutic molecule with highly potent anticancer effects that could address limitations of current IGFIR-targeting agents.

Polyacrylamide-co-acrylic acid (PA) added to shake flask cultures of Acetobacter xylinum at concentrations up to 3 g dm −3 resulted in increased production of bacterial cellulose. For PA concentrations of 0-3 g dm −3 , 7-day cellulose production rose monotonically from 2.7 ± 0.8 to 6.5 ± 0.5 g dm −3 at a shaker speed of 175 rpm, and from 1.7 ± 0.01 to 3.7 ± 0.5 g dm −3 at shaker speed of 375 rpm. Addition of PA also changed the morphology of the biomass from amorphous/stringy forms to spheroidal particles with diameters ≤2 mm. Similarly, bioreactor cultures grown in the absence of PA formed long fibrous masses which deposited on the internals, while those grown in the presence of 1-2 g dm −3 PA formed small discrete particles with diameters ≤0.1 mm. Tests performed with 1 and 2 g dm −3 PA, and stirrer speeds from 500 to 900 rpm, appeared to give the highest cellulose concentration of 5.3 ± 0.7 g dm −3 in 64-68.5 h in the presence of 2 g dm −3 PA at 700 rpm, although this value was statistically indistinguishable from that obtained at 1 g dm −3 PA and 900 rpm. A qualitative model is proposed to describe the mechanisms by which PA affects biomass morphology, resulting in its advantageous formation as small, dispersed, spheroidal pellets. Quantitative analysis of the results gave inverse correlations between both the fraction of fructose carbon going to cellulose synthesis and the specific fructose consumption rate, and the maximum cellulose concentration and the fraction of fructose carbon going to by-product formation. Since cellulose yield was almost universally improved by higher polyacrylamide concentration, it appears likely that increased viscosity reduces fructose uptake rate by limiting mass transfer.