| Abstrakt: |
The optimization of nutritional and operational conditions that favor the production of the biopolymer polyhydroxyalcanoate (PHA) by the halophilic bacterium Halomonas boliviensis was carried out in this study. In a Plackett Burman design the significance of six factors was evaluated: agitation, temperature, pH, initial concentration of glucose, nitrogen and KH2PO4. In a second experimental design the factors with high significance (temperature, pH and KH2PO4) were further studied applying the response surface methodology (Box Benkhen design). This design allowed obtaining a second order polynomial that modeled the response variables (biomass and PHA) to predict the values of the factors that maximizes biomass and PHA in the studied range, which were: 31 °C, 7.0 and 1.6 g/L for temperature, pH and KH2PO4, respectively. The optimal values were validated in fermentations using synthetic culture medium and a complex medium based on oil palm empty fruit bunch and gluten hydrolysates as carbon and nitrogen sources, respectively. Biomass and PHA concentrations of 9.2 and 6.5 g/L, respectively, were reached in the synthetic medium, which represent deviations of 26 and 4% with respect to the values predicted by the model. On the other hand, the biomass and PHA concentrations obtained with the hydrolysate-based medium was 70 and 35.4% that reached with the synthetic culture medium. [ABSTRACT FROM AUTHOR] |
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