Fructose-Based Production of Short-Chain-Length and Medium-Chain-Length Polyhydroxyalkanoate Copolymer by Arctic Pseudomonas sp. B14-6

• Published in: Polymers
• Main Authors: Tae-Rim Choi, Ye-Lim Park, Hun-Suk Song, Sun Mi Lee, Sol Lee Park, Hye Soo Lee, Hyun-Joong Kim, Shashi Kant Bhatia, Ranjit Gurav, Kwon-Young Choi, Yoo Kyung Lee, Yung-Hun Yang
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2021
• Subjects: Pseudomonas strain; polyhydroxyalkanoate; fructose syrup; fermentation; Organic chemistry; QD241-441; Arctic
• Online Access: https://doi.org/10.3390/polym13091398; https://doaj.org/article/c311799de67a47c5a2605ec2f0033cda

Arctic bacteria employ various mechanisms to survive harsh conditions, one of which is to accumulate carbon and energy inside the cell in the form of polyhydroxyalkanoate (PHA). Whole-genome sequencing of a new Arctic soil bacterium Pseudomonas sp. B14-6 revealed two PHA-production-related gene clusters containing four PHA synthase genes ( phaC ). Pseudomonas sp. B14-6 produced poly(6% 3-hydroxybutyrate- co -94% 3-hydroxyalkanoate) from various carbon sources, containing short-chain-length PHA (scl-PHA) and medium-chain-length PHA (mcl-PHA) composed of various monomers analyzed by GC-MS, such as 3-hydroxybutyrate, 3-hydroxyhexanoate, 3-hydroxyoctanoate, 3-hydroxydecanoate, 3-hydroxydodecenoic acid, 3-hydroxydodecanoic acid, and 3-hydroxytetradecanoic acid. By optimizing the PHA production media, we achieved 34.6% PHA content using 5% fructose, and 23.7% PHA content using 5% fructose syrup. Differential scanning calorimetry of the scl- co -mcl PHA determined a glass transition temperature (T g ) of 15.3 °C, melting temperature of 112.8 °C, crystallization temperature of 86.8 °C, and 3.82% crystallinity. In addition, gel permeation chromatography revealed a number average molecular weight of 3.6 × 10 4 , weight average molecular weight of 9.1 × 10 4 , and polydispersity index value of 2.5. Overall, the novel Pseudomonas sp. B14-6 produced a polymer with high medium-chain-length content, low T g , and low crystallinity, indicating its potential use in medical applications.