Effect of culture residence time on substrate uptake and storage by a pure culture of Thiothrix (CT3 strain) under continuous or batch feeding.
N Biotechnol
; 36: 1-7, 2017 May 25.
Article
em En
| MEDLINE
| ID: mdl-27986600
ABSTRACT
A pure culture of the filamentous bacterium Thiothrix, strain CT3, was aerobically cultured in a chemostat under continuous acetate feeding at three different culture residence times (RT 6, 12 or 22 d) and the same volumetric organic load rate (OLR 0.12gCOD/L/d). Cells cultured at decreasing RT in the chemostat had an increasing transient response to acetate spikes in batch tests. The maximum specific acetate removal rate increased from 25 to 185mgCOD/gCOD/h, corresponding to a 1.8 to 8.1 fold higher respective steady-state rate in the chemostat. The transient response was mainly due to acetate storage in the form of poly(3-hydroxybutyrate) (PHB), whereas no growth response was observed at any RT. Interestingly, even though the storage rate also decreased as the RT increased, the storage yield increased from 0.41 to 0.50 COD/COD. This finding does not support the traditional view that storage plays a more important role as the transient response increases. The transient response of the steady-state cells was much lower than in cells cultured under periodic feeding (at 6 d RT, from 82 to 247mgCOD/gCOD/h), with the latter cells showing both storage and growth responses. On the other hand, even though steady-state cells had no growth response and their storage rate was also less, steady-state cells showed a higher storage yield than cells cultured under dynamic feeding. This suggests that in Thiothrix strain CT3, the growth response is triggered by periodic feeding, whereas the storage response is a constitutive mechanism, independent from previous acclimation to transient conditions.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Reatores Biológicos
/
Thiothrix
Idioma:
En
Revista:
N Biotechnol
Assunto da revista:
BIOLOGIA MOLECULAR
/
ENGENHARIA BIOMEDICA
Ano de publicação:
2017
Tipo de documento:
Article