Accumulation of Methylglyoxal in Anaerobically Grown Escherichia coli and Its Detoxification by Expression of the Pseudomonas putida Glyoxalase I Gene
✍ Scribed by Marie M. Zhu; Frank A. Skraly; Douglas C. Cameron
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 247 KB
- Volume
- 3
- Category
- Article
- ISSN
- 1096-7176
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✦ Synopsis
Anaerobic glycerol fermentation by Escherichia coli strains expressing genes from the Klebsiella pneumoniae dha regulon showed that cell growth and 1,3-propanediol (1,3-PD) production are significantly inhibited when 5 gÂL or higher of glycerol is initially present. One reason for this inhibition may be methylglyoxal (MG) accumulation. Assays of both intracellular and extracellular MG levels indicated an accumulation of MG in anaerobic glycerol fermentation of transgenic E. coli. Pseudomonas putida glyoxalase I was expressed in the transgenic E. coli to enhance MG detoxification. The activity of glyoxalase I in the transgenic E. coli with the P. putida glyoxalase I under anaerobic conditions was 12-fold higher than that in the control cells. Compared to the control cells, the transgenic cells with the P. putida glyoxalase I displayed a reduction of 35 43P in intracellular MG and a decrease of 30P in extracellular MG. These decreases were statistically significant (P >94). Furthermore, the expression of the P. putida glyoxalase I in the transgenic E. coli markedly improved cell growth and resulted in a 50P increase in 1,3-PD production.