title: Fed-batch production of poly-3-hydroxydecanoate from decanoic acid.
abstract: Decanoic acid is an ideal substrate for the synthesis of medium-chain-length poly-3-hydroxyalkanoate (MCL-PHA), but its use for this purpose has only previously been studied in shake-flasks likely due to its surfactant properties, low aqueous solubility and high melting temperature. A fed-batch fermentation process was developed for the production of MCL-PHA from decanoic acid using Pseudomonas putida KT2440. Decanoic acid was kept in liquid form by heating or by mixing with acetic acid to prevent crystallization. Different ratios of decanoic acid:acetic acid:glucose (DA:AA:G) were fed to produce a specific growth rate of 0.15 h(-1). This method produced a maximum of 39 g L(-1) dry biomass containing 67% MCL-PHA when the DA:AA:G ratio was 5:1:4. However, a declining growth rate occurred in the late stage of fermentation, resulting in decanoic acid accumulation in the bioreactor leading to foaming. The duration of MCL-PHA production was extended by shifting from exponential to linear feeding before accumulation of decanoic acid. This resulted in 75 g L(-1) biomass containing 74% PHA and an overall PHA productivity of 1.16 g L(-1)h(-1) with the production of each gram of PHA requiring only 1.16 g of decanoic acid. The final PHA composition (on a molar basis) was 78% 3-hydroxydecanoate, 11% 3-hydroxyoctanoate and 11% 3-hydroxyhexanoate.
authors.affiliation: Chemical Engineering, Queen's University, Kingston, ON K7L 3N6, Canada.
authors.forename: Jie
authors.initials: J
authors.lastname: Gao
authors.affiliation: Chemical Engineering, Queen's University, Kingston, ON K7L 3N6, Canada.
authors.forename: Juliana A
authors.initials: JA
authors.lastname: Ramsay
authors.affiliation: Chemical Engineering, Queen's University, Kingston, ON K7L 3N6, Canada; Polyferm Canada Inc., RR1 Harrowsmith, ON K0H 1V0, Canada. Electronic address: Bruce.Ramsay@Polyferm.com.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Ramsay
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D061249:Batch Cell Culture Techniques / Q000379:methods*; D018533:Biomass; D019149:Bioreactors; D002208:Caproates / Q000378:metabolism; D002210:Caprylates / Q000378:metabolism; D003652:Decanoic Acids / Q000378:metabolism*; D005285:Fermentation; D005947:Glucose / Q000378:metabolism; D011091:Polyesters / Q000378:metabolism*; D016958:Pseudomonas putida / Q000378:metabolism
chemical_list: D002208:Caproates; D002210:Caprylates; D003652:Decanoic Acids; D011091:Polyesters; C488799:poly(3-hydroxydecanoate); C045051:3-hydroxyhexanoic acid; C031071:decanoic acid; C101940:3-hydroxyoctanoic acid; D005947:Glucose; D019342:Acetic Acid
keywords: Decanoic acid; Fed-batch; Fermentation; MCL-PHA; Medium-chain-length poly-3-hydroxyalkanoate; Pseudomonas putida