This paper describes work carried out at the Department of Chemical Engineering at UCL into the use of e-assessment in a second year module and, in particular, the student perceptions of this mode of assessment. Three quizzes were implemented in Moodle, the first two as formative assessment and the final quiz as summative assessment. The results were very encouraging and practically all students engaged with the process. An online survey was delivered to all students after the module, which showed that the students felt that e-assessment added value to their learning and they would like to see it implemented in other modules. The quizzes were intended to be mainly beneficial to the weaker students as it gave them an opportunity to go over key aspects of the material in their own time. Interestingly, the stronger students were even more in favour of e-learning than the weaker students, for whom the quizzes were originally designed.

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The multivessel batch column consists of a reboiler, several column sections, intermediate vessels and a condenser vessel. This configuration provides a generalization of previously proposed batch-distillation schemes, including the inverted column and the middle-vessel column. The total reflux operation of the multivessel batch-distillation column was presented recently, and the main contribution of this article is to propose a simple feedback control strategy for its operation. We propose to adjust the vessel holdups indirectly by manipulating the reflux flow out of each vessel to control the temperature at some location in the column section below. The feasibility of this strategy is demonstrated by simulations.

Increased interest in uncon®entional batch distillation column configurations offers

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An integrated experimental and modeling approach for the design of high productivity protein A chromatography is presented to maximize productivity in bioproduct manufacture. The approach consists of four steps: (1) small-scale experimentation, (2) model parameter estimation, (3) productivity optimization and (4) model validation with process verification. The integrated use of process experimentation and modeling enables fewer experiments to be performed, and thus minimizes the time and materials required in order to gain process understanding, which is of key importance during process development. The application of the approach is demonstrated for the capture of antibody by a novel silica-based high performance protein A adsorbent named AbSolute. In the example, a series of pulse injections and breakthrough experiments were performed to develop a lumped parameter model, which was then used to find the best design that optimizes the productivity of a batch protein A chromatographic process for human IgG capture. An optimum productivity of 2.9 kg L⁻¹ day⁻¹ for a column of 5mm diameter and 8.5 cm length was predicted, and subsequently verified experimentally, completing the whole process design approach in only 75 person-hours (or approximately 2 weeks).

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Fouling of chromatographic resins over their operational lifetimes can be a significant problem for commercial bioseparations. In this article, scanning electron microscopy (SEM), batch uptake experiments, confocal laser scanning microscopy (CLSM) and small-scale column studies were applied to characterize a case study where fouling had been observed during process development. The fouling was found to occur on an anion exchange (AEX) polishing step following a protein A affinity capture step in a process for the purification of a monoclonal antibody. Fouled resin samples analyzed by SEM and batch uptake experiments indicated that after successive batch cycles, significant blockage of the pores at the resin surface occurred, thereby decreasing the protein uptake rate. Further studies were performed using CLSM to allow temporal and spatial measurements of protein adsorption within the resin, for clean, partially fouled and extensively fouled resin samples. These samples were packed within a miniaturized flowcell and challenged with fluorescently labeled albumin that enabled in situ measurements. The results indicated that the foulant has a significant impact on the kinetics of adsorption, severely decreasing the protein uptake rate, but only results in a minimal decrease in saturation capacity. The impact of the foulant on the kinetics of adsorption was further investigated by loading BSA onto fouled resin over an extended range of flow rates. By decreasing the flow rate during BSA loading, the capacity of the resin was recovered. These data support the hypothesis that the foulant is located on the particle surface, only penetrating the particle to a limited degree. The increased understanding into the nature of the fouling can help in the continued process development of this industrial example.Scanning electron microscopy (SEM), batch uptake experiments, confocal laser scanning microscopy (CLSM) and small-scale column experiments were applied to characterize a case study where fouling had been observed on an anion exchange chromatography in a monoclonal antibody process. The results suggest the foulant is located on the particle surface, resulting in a minimal decrease in saturation capacity, but having a significant impact on the kinetics of adsorption, severely decreasing protein uptake rate.