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Sangkharak,Kanokphorn; Prasertsan,Poonsuk. |
Three halotolerant bacterial strains; Rhodobacter sphaeroides ES16 (the wild type) and the two mutant strains of R. sphaeroides ES16, namely N20 and U7, were cultivated in glutamate-malate (GM) medium and screened for production of polyhydroxybutyrate (PHB). The mutant strains N20 and U7 were found to accumulate PHB (53.9 and 42.0% of DCW, respectively) 3.6 and 2.8 times higher than the wild type strain (19.5% of DCW), respectively. R. sphaeroides N20 were selected for studies on the effects of nutrient and environmental conditions on PHB accumulation. The optimal condition was 4 g/l acetate, 0.02 g/l (NH4)2SO4, C/N ratio of 6:1, 1.0 g/l K2HPO4, 1.0 g/l KH2PO4 and 3% NaCl with initial pH at 7.0. Under this optimal condition, the maximum PHB accumulation... |
Tipo: Journal article |
Palavras-chave: Aerobic-dark cultivation; Optimization; PHB; Polyhydroxybutyrate; Rhodobacter sphaeroides. |
Ano: 2008 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582008000300009 |
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Sattayasamitsathit,Supalak; Methacanon,Pawadee; Prasertsan,Poonsuk. |
The batch fermentation of 1,3-propanediol (1,3-PD) by Klebsiella pneumoniae SU6 at different crude glycerol concentration (40-100 g l-1), pH (6.5-7.5) and temperature (31-40ºC) combined with two-phase pH-controlled strategy was investigated. Effect of feeding rate (0.10-0.15 L h-1) was studied in fed-batch fermentation. In batch fermentation, the optimal condition was 60 g l-1 crude glycerol, pH control at 6.5 and cultivation temperature at 37ºC. The maximum 1,3-PD of 20 g l-1, the yield of 0.34 g 1,3-PD g-1 glycerol consumed and the productivity of 1.25 g l-1 h-1 were achieved at 16 hrs cultivation. The by-products were acetic acid and succinic acid at 2.7 and 1.1 g l-1, respectively. Two-phase pH-controlled strategy gave better results (24.95 g l-1... |
Tipo: Journal article |
Palavras-chave: 1; 3-propanediol crude glycerol fed-batch fermentation Klebsiella pneumonia two-phase pH-control. |
Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582011000600004 |
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