Breakage of transgenic tobacco roots for monoclonal antibody release in an ultra-scale down shearing device.
Bottom Line: A possible method for extraction of MAbs from roots is by homogenization, breaking the roots into fragments to release the antibody.Size distributions of the remaining intact roots and root fragments were obtained as a function of shearing time.It was postulated that root breakage in such a high shearing device was due to root-impeller collisions and the particle size data suggest that roots colliding with the impeller were completely fragmented into debris particles of the order of 0.1 mm in length.
Affiliation: Department of Biochemical Engineering, University College London, London, United Kingdom.Show MeSH
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Mentions: The shearing device was a flat-bottomed, cylindrical mixing tank made from Perspex (Fig. 2); the actual outer casing on this device was very large, so that the internal diameter and the total height of the chamber were 0.055 and 0.01 m respectively. The impeller diameter was 0.03 m giving a large impeller to tank diameter ratio (0.545) which meant that high radial flow velocities could be achieved. The impeller consisted of eight blades with a serrated edge with a blade width of 0.008 m and a thickness of 0.0015 m.The chamber volume and suspension volume were 24 and 7 mL, respectively. An impeller rotational speed of 75 s−1 was chosen since it was above the visually determined minimum speed for root suspension, that is, the minimum impeller speed required to keep the roots suspended in the vessel for longer than 1–2 s (Zwietering, 1958). The Reynolds number at this speed was 6.8 × 107, implying turbulent flow. In order to estimate the (mean) frequency of passage of the suspension through the impeller, f, it was necessary to determine the Power number for the novel impeller geometry used in these experiments. Hence this was measured as described in Gill et al. (2008). The measurements were carried out in triplicate, at two different speeds.
Affiliation: Department of Biochemical Engineering, University College London, London, United Kingdom.