Hi James, The first place I'd look is oxygen conc, as you'll get different aeration from different vessel shapes/sizes. You could play around with shaking speed and/or flask geometry to try to get more or less aeration.
Shane Caldwell McGill University On Tue, Jan 15, 2013 at 9:48 AM, Murray, James W <j.w.mur...@imperial.ac.uk>wrote: > Dear All. > > A question on protein expression. > We have been doing small scale test expressions in 15ml of terrific > broth+kanamycin using E.coli KRX cells in falcon tubes. On reaching > OD600 of ~0.6 we induced with rhamnose+IPTG and expressed for 4 hours > at 37 C. There is a big band corresponding to our protein in the > soluble fraction and not much in the insoluble fraction. However, on > scaling up to 1 L TB cultures (with same concentrations of kanamycin > and inducing with same concs of rhamnose+IPTG) we don't get strong > over expression. Has anyone else experienced problems when scaling up > expression? (and more importantly, solved them?) > > best wishes > > James > > > -- > Dr. James W. Murray > David Phillips Research Fellow > Division of Molecular Biosciences > Imperial College, LONDON > Tel: +44 (0)20 759 48895
