| dc.description.abstract | Polyhydroxybutyrate (PHB), a type of polyhyroxyalkanoate (PHA) bioplastic, is an attractive alternative to traditional petrochemical-derived plastics, such as polypropylene. However, PHB is costly to produce due to high feedstock and extraction costs. Crude glycerol from biodiesel production is a potential economic carbon source for PHA production, but crude glycerol often contains high levels of impurities, such as sodium salts and methanol, which might inhibit microbial growth. This study investigated the ability of Pseudomonas oleovorans to produce PHB when grown on glycerol and glycerol impurities, followed by the application of bacteriophage to extract PHB from PHB-bearing cells.
During growth on glycerol, P. oleovorans was able to accumulate up to 31.1 % of cell dry weight (CDW) as PHB. The accumulation of PHB was influenced by molar carbon:nitrogen ratios (C/N) in the growth media, with the highest accumulation of PHB occurring at a C/N ratio of 21.5. Additionally, P. oleovorans was found to tolerate the common glycerol impurities NaCl (0-2 g/L) and methanol (0-2 g/L) with no significant loss of PHB accumulation. A bacteriophage, Ke14, targeting P. oleovorans was isolated from soil samples in College Station, TX. Ke14 was found to be able to lyse PHB-bearing cells once they were allowed to return to exponential growth stage.
We have shown P. oleovorans is an attractive candidate for PHB production due to its ability to produce PHB in the presence of common glycerol impurities found in biodiesel by-product crude glycerol with no adverse effect on PHB accumulation. Bacteriophage facilitated lysis of glycerol containing P. oleovorans was observed. This indicates that alternative methods to traditional PHB extraction methods may be feasible. | en |
