Growth of Corynebacterium glutamicum in glucose-limited continuous cultures under high osmotic pressure. Influence of growth rate on the intracellular accumulation of proline, glutamate and trehalose

1995 ◽  
Vol 44 (3-4) ◽  
pp. 496-500 ◽  
Author(s):  
S. Guillouet ◽  
J. M. Engasser
1995 ◽  
Vol 31 (11) ◽  
pp. 173-180 ◽  
Author(s):  
M. van der Ploeg ◽  
M. E. Dennis ◽  
M. Q. de Regt

Relative abundance of Oscillatoria cf. chalybea was monitored during May-November, 1993, in 40 ponds at four catfish farms located 50-100 km apart in west central Mississippi, USA. The occurrence of O. cf.chalybea coincided with the period that water temperatures remained above 20°C. In 70% of ponds, O. cf.chalybea was present for a period of 2-20 weeks. The alga recurred in all ponds where it had been present in 1990 and 1991. The effects of temperature and light availability on growth rate and 2-methylisoborneol (MIB) production of O. cf. chalybea were studied in continuous cultures. At 28°C, maximum specific growth rates were 0.8 d−1 (24 h light) and 0.6 d−1 (14 h light :10 h dark). Algal cells contained less MIB when adapted to the shorter light cycle than when grown under continuous light. Specific growth rate of O. cf.chalybea dropped from 0.3 to 0.1 d−1 when temperature was changed from 21 to 19.5°C (14 h light).


2009 ◽  
Vol 75 (11) ◽  
pp. 3419-3429 ◽  
Author(s):  
Hideo Kawaguchi ◽  
Miho Sasaki ◽  
Alain A. Vertès ◽  
Masayuki Inui ◽  
Hideaki Yukawa

ABSTRACT Corynebacterium glutamicum ATCC 31831 grew on l-arabinose as the sole carbon source at a specific growth rate that was twice that on d-glucose. The gene cluster responsible for l-arabinose utilization comprised a six-cistron transcriptional unit with a total length of 7.8 kb. Three l-arabinose-catabolizing genes, araA (encoding l-arabinose isomerase), araB (l-ribulokinase), and araD (l-ribulose-5-phosphate 4-epimerase), comprised the araBDA operon, upstream of which three other genes, araR (LacI-type transcriptional regulator), araE (l-arabinose transporter), and galM (putative aldose 1-epimerase), were present in the opposite direction. Inactivation of the araA, araB, or araD gene eliminated growth on l-arabinose, and each of the gene products was functionally homologous to its Escherichia coli counterpart. Moreover, compared to the wild-type strain, an araE disruptant exhibited a >80% decrease in the growth rate at a lower concentration of l-arabinose (3.6 g liter−1) but not at a higher concentration of l-arabinose (40 g liter−1). The expression of the araBDA operon and the araE gene was l-arabinose inducible and negatively regulated by the transcriptional regulator AraR. Disruption of araR eliminated the repression in the absence of l-arabinose. Expression of the regulon was not repressed by d-glucose, and simultaneous utilization of l-arabinose and d-glucose was observed in aerobically growing wild-type and araR deletion mutant cells. The regulatory mechanism of the l-arabinose regulon is, therefore, distinct from the carbon catabolite repression mechanism in other bacteria.


2013 ◽  
Vol 7 (Suppl 6) ◽  
pp. P108 ◽  
Author(s):  
Mauricio Vergara ◽  
Silvana Becerra ◽  
Julio Berrios ◽  
Juan Reyes ◽  
Cristian Acevedo ◽  
...  

2016 ◽  
Vol 62 (12) ◽  
pp. 983-992 ◽  
Author(s):  
Jianzhong Xu ◽  
Junlan Zhang ◽  
Dongdong Liu ◽  
Weiguo Zhang

The phosphoenolpyruvate:glucose phosphotransferase system (PTSGlc) is the major pathway of glucose uptake in Corynebacterium glutamicum. This study investigated glucose consumption rate, cell growth, and metabolite changes resulting from modification of PTSGlc. The classical l-lysine producer C. glutamicum XQ-8 exhibited low glucose consumption, cell growth, and l-lysine production rates, whereas these parameters were significantly increased during cultivating on glucose plus maltose, through inactivation of SugR, or by overexpression of PTSGlc genes. XQ-8sugR::cat/pDXW-8-ptsI exhibited the highest increase in glucose consumption, growth rate, and l-lysine production, followed by XQ-8sugR::cat/pDXW-8-ptsG. However, overexpression of ptsH had little effect on the above-mentioned factors. Although co-overexpression of ptsGHI led to the highest glucose consumption, growth rate, and final l-lysine production; the l-lysine production rate was lower than that of XQ-8sugR::cat/pDXW-8-ptsIH. In fed-batch fermentation, XQ-8sugR::cat/pDXW-8-ptsIH had a higher growth rate of 0.54 h−1 to a dry cell mass of 66 g·L−1 after 16 h, and had a higher l-lysine production rate of 159.2 g·L−1 after 36 h. These results indicate that modification of the sugar transport systems improves amino acid production, especially for mutants obtained by repeated physical and (or) chemical mutagenesis. However, modification of these systems needs to be performed on a case-by-case basis.


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