Team:UCL London/Fermenter Mechanics

Fermentation set-up

Mechanical Design of 1000L Fermenter

This report was conducted to estimate the dimensions and the materials needed for the construction of a 1000L fermenter for the production of Fab fragments (fragmented antigen binding) are the regions of an antibody expressed and secreted in E.coli cells. For the estimation of the dimensions of the fermenter empirical equations and rules of thumbs were exploited. The dimensions and the fermenter properties like the diameter, the height as well as the impellers speed, the baffles position and the driveshaft size were estimated on a scale- down model. The material used for the fabrication of the fermenter, the head end, the ports and the pipes is stainless steel to resist corrosion and maintain a clean and sterile vessel. The diameter of the vessel is 0.8m and the height is 2m.

The thickness of the wall is 6mm with a 0.15 m jacket surround it. The impeller’s speed is 3.3 m/s and the impeller used is Ruston Turbine four blades, suitable for the growth of E.coli cells. Therefore all the power requirements were satisfied ensuring the viability of the design. Five spray balls were found to be enough for a sufficient cleaning of the fermenter with their 360° coverage and placed on the inside of the torispherical head in a cross shape. Then the flowrate in the pipes was predicted enabling the calculation of the diameter. Basically all the information specified for every single part of the fermenter was taken from recommendations, advice from experts, theoretical predictions as well as engineering justifications. Last but not least emphasis is given on the importance of maintenance and annual shutdowns of the plant as well as regular checks to ensure its proper operation. The above graph, show the phases in the cell growth in a typical batch. The table, describes each phase and provides the specific growth rate for each phase. Reproduced from P.M.Doran (2006), pp:277

The above graphs, show the modeling of the growth kinetics and the typical profiles of biomass and substrate concentration during a batch process. Reproduced from Nielsen et al (2002), pp:247