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Monitoring GFP‐operon fusion protein expression during high cell density cultivation of Escherichia coli using an on‐line optical sensor
Author(s) -
DeLisa Matthew P.,
Li Jincai,
Rao Govind,
Weigand William A.,
Bentley William E.
Publication year - 1999
Publication title -
biotechnology and bioengineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.136
H-Index - 189
eISSN - 1097-0290
pISSN - 0006-3592
DOI - 10.1002/(sici)1097-0290(19991005)65:1<54::aid-bit7>3.0.co;2-r
Subject(s) - green fluorescent protein , operon , fusion protein , chloramphenicol acetyltransferase , escherichia coli , recombinant dna , biology , arabinose , biochemistry , reporter gene , chemistry , microbiology and biotechnology , fermentation , gene expression , gene , xylose
Synthesis of an operon fusion protein was investigated in batch and fed‐batch cultures at high cell densities of recombinant Escherichia coli JM105 [pBAD‐GFP::CAT]. Glucose‐limited growth was achieved without accumulation of inhibitory byproducts allowing high cell densities (110 g L −1 DCW) to be attained. This was believed to be the highest reported value for dry cell mass of E. coli strain JM105 expressing two recombinant proteins. Transcription of the two reporter genes, green fluorescent protein (GFP) and chloramphenicol acetyltransferase (CAT), was under the control of the p BAD promoter of the araBAD (arabinose) operon. Each protein was independently translated via separate ribosome binding sites. CAT served as a model recombinant protein product to illustrate the noninvasive quantitative reporting ability of GFP during high cell density fermentations. Expression of GFP was monitored on‐line using an intensity‐based optical sensor. A linear correlation between the on‐line GFP intensity and the enzymatic activity of CAT allowed for in vivo real‐time quantitative monitoring of a fermentation product under conditions of high biomass concentration and high productivity. © 1999 John Wiley & Sons, Inc. Biotechnol Bioeng 65: 54–64, 1999.