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Q: Glycerol in growth media of E.coli influence on recombinant protein production and recovery, oxygen limitation - influence on recombinant protein production and recovery ??

Bjoern Arne Naess bjorn at ik.hist.no
Mon May 22 16:21:34 EST 1995

Help needed.

Two of my students: Inger Beate Foelstad and Hilde Toerset works on a project 
concerning production and recovery of a recombinant protein expressed in 
E. coli. for  their diploma at Soer-Troendelag College.

The recombinant protein production is regulated by the regulator of 
the lac-operon and is indused by isopropylthiogalactoside, IPTG.
The recombinant protein produced is intracellular.

Using LB- medium with and without glycerol (15 g/liter).
They observed a reduction in recombinant protein yield when medium contained
glycerol. The pH was kept steady at 7.0 through all fermentations.

Can glycerol have a influence on protein solubility ?
Can glycerol inhibit the induser or the expression of the protein?

In some fermentations they had oxygen limitation for the last hour - 
coresponding to the inducing periode - they  observed reduction in recombinant 
protein yield - even though the biomass production was adequate.

How can oxygen influence on production of induced recombinant protein while it 
has no influence on the biomass production in the same run ?

Have You any experience with this or know anyone who might ??

We hope for suggestions, comments or hints on this.

Thank You in advance!

Please send answere by Email to:


Bjorn at ik.hist.no

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