Process analysis of the conversion of styrene to biomass and medium chain length polyhydroxyalkanoate in a two-phase bioreactor.
Biotechnol Bioeng
; 108(10): 2447-55, 2011 Oct.
Article
em En
| MEDLINE
| ID: mdl-21520026
ABSTRACT
The improvement and modeling of a process for the supply of the volatile aromatic hydrocarbon, styrene, to a fermentor for increased biomass production of the medium chain length polyhydroxyalkanoate (mcl-PHA) accumulating bacterium Pseudomonas putida CA-3 was investigated. Fed-batch experiments were undertaken using different methods to provide the styrene. Initial experiments where styrene was supplied as a liquid to the bioreactor had detrimental effects on cell growth and inhibited PHA polymer accumulation. By changing the feed of gaseous styrene to liquid styrene through the air sparger a 5.4-fold increase in cell dry-weight was achieved (total of 10.56 g L(-1)) which corresponds to a fourfold improvement in PHA production (3.36 g L(-1)) compared to previous studies performed in our laboratory (0.82 g L(-1)). In addition this final improved feeding strategy reduced the release of styrene from the fermentor 50-fold compared to initial experiments (0.12 mL total styrene released per 48 h run). An unstructured kinetic model was developed to describe cell growth along with substrate and oxygen utilization. The formation of dispersed gas (air) and liquid (styrene) phases in the medium and the transfer of styrene between the aqueous and dispersed liquid droplet phases was also modeled. The model provided a detailed description of these phase transitions and helped explain how the feeding strategy led to improved process performance in terms of final biomass levels. It also highlighted the key factors to be considered during further process improvement.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Pseudomonas putida
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Biomassa
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Reatores Biológicos
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Estireno
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Poli-Hidroxialcanoatos
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Modelos Biológicos
Tipo de estudo:
Prognostic_studies
Idioma:
En
Ano de publicação:
2011
Tipo de documento:
Article