A microporous walled micro-capillary film module for cation-exchange protein chromatography

AbstractOpportunities exist in preparative chromatography for alternative chromatography media that possess high binding capacity and throughput, but are also economically feasible for single use disposability and avoid column packing. An ion-exchange functionalised, microporous walled micro-capillary film (MMCF), has been developed as a module for cation-exchange separation of proteins. A MMCF module has been operated on a standard AKTA chromatography system at pressures up to 1.5MPa and superficial flow velocities up to 54,000cmh−1. The dynamic binding capacity of the MMCF module at 10% breakthrough was 13.8mglysozyme/ml adsorbent volume, which is comparable to the capacity of current commercial adsorbents. Frontal analysis studies using a mixture of lysozyme and bovine serum albumin (BSA) have shown that lysozyme can be isolated free of BSA to the limit of detection of the SDS gel assay used. 98.8% of the total sample eluted was the target protein lysozyme with only 1.2% BSA impurity. MMCF may thus be a viable chromatographic medium for preparative protein chromatography

A facile route to a polymer-supported IBX reagent

A three-step preparation of a polymer-supported IBX reagent from poly(p-methylstyrene) is reported. This reagent has been used successfully for the efficient oxidation of a series of alcohols to the corresponding aldehydes

Kinetics of oxidation of hydroquinone by polymer-supported hypervalent iodine oxidant, iodoxybenzoic acid

lodoxybenzoic acid has been covalently attached to polystyrene-co-divinylbenzene beads at different capacities and the hydroquinone oxidation kinetics have been studied in a stirred batch reactor. An initial rate analysis yielded a first order dependence on the concentration of the substrate hydroquinone and the supported IBX reagent implying chemical reaction is rate limiting. An observed second order rate constant of 1.3 (+/-0.3) M-1 s(-1) was obtained for the initial rate of oxidation using the supported reagent. The activation energy was halved at later stages of reaction (greater than 50% conversion of the reagent), suggesting that intraparticle diffusion then become rate limiting as the conversion of the reagent in the bead proceeded. Unreacted shrinking core and pseudo-homogeneous diffusion-reaction models have been used to analyse the experimental data to yield values for the effective diffusivity of hydroquinone in the polymer matrix of (1.0-1.2) x 10(-11) m(2)/s. The performance of the supported reagent in a packed bed has also been studied by continuous flow of a solution of hydroquinone. The product quinone concentration profile at the reactor exit showed limited dependence on the flow-rates studied. Pronounced tailing of the product concentration was obtained for more highly loaded beads, which was attributed to hindered diffusion limiting access to the residual reactive sites

A semi-theoretical model of vertical solids distribution during slurry mixing

Available from British Library Document Supply Centre- DSC:3604.9222(NIAE-DN--1369) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Bioprocess modelling of biohydrogen production by Rhodopseudomonas palustris:Model development and effects of operating conditions on hydrogen yield and glycerol conversion efficiency

This is the accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S0009250915001815.This research explores the photofermentation of glycerol to hydrogen by Rhodopseudomonas palus-\ud tris, with the objective to maximise hydrogen production. Two piecewise models are designed to\ud simulate the entire growth phase of R. palustris; a challenge that few dynamic models can accomplish.\ud The parameters in both models were fitted by the present batch experiments through the\ud solution of the underlying optimal control problems by means of stable and accurate discretisation\ud techniques. It was found that an initial glutamate to glycerol ratio of 0.25 was optimal, and\ud was independent of the initial biomass concentration. The glycerol conversion efficiency was found\ud to depend on initial biomass concentration and its computational peak is 64.4%. By optimising\ud a 30-day industrially relevant batch process, the hydrogen productivity was improved to be 37.7\ud mL?g biomass-1?hr-1 and the glycerol conversion efficiency was maintained at 58%. The models can\ud then be applied as the connection to transfer biohydrogen production from laboratory scale into\ud industrial scale.Authors N. Xiao and\ud Dr. K. T. Mahbubani are funded through the KACST-Cambridge Center for Advanced Material\ud Manufacture, the author E. A. del Rio-Chanona is found by CONACyT scholarship No. 522530\ud from the Secretariat of Public Education and the Mexican government