Bioconversion of styrene to poly(hydroxyalkanoate) (PHA) by a new bacterial strain Pseudomonas putida NBUS12

• Main Authors: Tan, Giin-Yu Amy, Chen, Chia-Lung, Ge, Liya, Li, Ling, Tan, Swee Ngin, Wang, Jing-Yuan
• Other Authors: School of Civil and Environmental Engineering
• Format: Article
• Language: English
• Published: 2015
• Subjects: DRNTU::Science::Biological sciences::Microbiology::Bacteria
• Online Access: https://hdl.handle.net/10356/107080; http://hdl.handle.net/10220/25587
• Institution: Nanyang Technological University

Styrene is a toxic pollutant commonly found in waste effluents from plastic processing industries. We herein identified and characterized microorganisms for bioconversion of the organic eco-pollutant styrene into a valuable biopolymer medium-chain-length poly(hydroxyalkanoate) (mcl-PHA). Twelve newly-isolated styrene-degrading Pseudomonads were obtained and partial phaC genes were detected by PCR in these isolates. These isolates assimilated styrene to produce mcl-PHA, forming PHA contents between 0.05±0.00 and 23.10±3.25% cell dry mass (% CDM). The best-performing isolate was identified as Pseudomonas putida NBUS12. A genetic analysis of 16S rDNA and phaZ genes revealed P. putida NBUS12 as a genetically-distinct strain from existing phenotypically-similar bacterial strains. This bacterium achieved a final biomass of 1.28±0.10 g L−1 and PHA content of 32.49±2.40% CDM. The extracted polymer was mainly comprised of 3-hydroxyhexanoate (C6 ), 3-hydroxyoctanoate (C8 ), 3-hydroxydecanoate (C10 ), 3-hydroxydodecanoate (C12 ), and 3-hydroxytetradecanoate (C14 ) monomers at a ratio of 2:42:1257:17:1. These results collectively suggested that P. putida NBUS12 is a promising candidate for the biotechnological conversion of styrene into mcl-PHA.