Effect of postinduction nutrient feed composition and use of lactose as inducer during production of thermostable xylanase in Escherichia coli glucose-limited fed-batch cultivations

Summary, in English

Escherichia coli is a microorganism routinely used in the production of heterologous proteins. The overexpression of a xylanase (Xyn10A Delta NC), which originated from the thermophile Rhodo-thermus marinus cloned under the control of the strong T7/lac promoter in a defined medium (mAT) using a substrate-limited feed strategy, was however shown to impose a significant metabolic burden on host cells. This resulted in a decreased cell growth rate and ultimately also a decreased target protein production. The investigation hence centers on the effect of some selected nutrient feed additives (amino acid [Cys] or TCA-intermediates [citrate, succinate, malate]) used to relieve the metabolic burden imposed during the feeding and postinduction phases of these glucose-limited fed-batch cultivations. The use of either succinic acid or malic acid as feed-additives resulted in an increase in production of approximately 40% of the heterologous thermostable xylanase. Furthermore, use of lactose as an alternative inducer of the T7/lac promoter was also proven to be a suitable strategy that significantly prolonged the heterologous protein production phase as compared with induction using isopropyl P-D-thiogalactopyranoside (IPTG).

• Author: Santosh Ramchuran; Olle Holst; Eva Nordberg Karlsson
• Department/s: Biotechnology
• Publishing year: 2005
• Language: English
• Pages: 477-484
• Publication/Series: Journal of Bioscience and Bioengineering
• Volume: 99
• Issue: 5
• Links: http://dx.doi.org/10.1263/jbb.99.477
• Document type: Journal article
• Publisher: Elsevier
• Topic: Industrial Biotechnology
• Status: Published
• ISBN/ISSN/Other: ISSN: 1347-4421