Production of medium-chain-length polyhydroxyalkanoate by Pseudomonas oleovorans grown in sugary cassava extract supplemented with andiroba oil

Abstract

Pseudomonas oleovorans were grown on sugary cassava extracts supplemented with andiroba oil for the synthesis of a mediumchain-length polyhydroxyalkanoate (PHA MCL ). The concentration of total sugars in the extract was approximately: 40 g/L in culture 1, 15 g/L in cultures 2 and 3, and 10 g/L in culture 4. Supplementation with 1% andiroba oil and 0.2 g/L of (NH 4 ) 2 HPO 4 was performed 6.5 hours after growth in culture 3, and supplementation with the same amount of andiroba oil and 2.4 g/L of (NH 4 ) 2 HPO 4 was performed at the beginning of growth in culture 4. The synthesis resulted mainly in 3-hydroxy-decanoate and 3-hydroxy-dodecanoate units; 3-hydroxy-butyrate, 3-hydroxy-hexanoate; and 3-hydroxy-octanoate monomers were also produced but in smaller proportions. P. oleovorans significantly accumulated PHA MCL in the deceleration phase of growth with an oxygen limitation but with sufficient nitrogen concentration to maintain cell growth. The sugary cassava extract supplemented with andiroba oil proved to be a potential substrate for PHA MCL production.

Optimization of Propagation Medium for Enhanced Polyhydroxyalkanoate Production by Pseudomonas oleovorans

“…PHA accumulation is initiated by depletion of the essential nutrient, but this is not compatible with high biomass production. Two-step cultivation, possibly fed-batch or continuous cultivation, appears to be an effective way to produce a secondary metabolite [26,[35][36][37][38]. This study was aimed to optimize the propagation medium resulting in maximum biomass yield in the first step of bacterial PHA production.…”

“…This study was aimed to optimize the propagation medium resulting in maximum biomass yield in the first step of bacterial PHA production. The composition of the propagation medium frequently used in published studies [35][36][37]39,40] was chosen. The necessity of individual components present in the medium can be verified using a Plackett-Burman design.…”

“…First, it is necessary to know the producer's requirements as well as the optimum conditions for the growth and PHA production. In the case of Pseudomonas cultivation, several authors [26,[35][36][37][38] used a two-step cultivation method to maximize biomass production and subsequently stimulate PHA production. The first phase is the production of bacterial biomass in order to obtain the highest possible density and adjust growth conditions of the producer.…”

Synthesis Gas (Syngas)-Derived Medium-Chain-Length Polyhydroxyalkanoate Synthesis in Engineered Rhodospirillum rubrum

“…Alternatively, readily available fatty acids that are metabolized to 3-hydroxyacyl-CoA through ␤-oxidation can be converted to a substrate for the PHA polymerase PhaC. Many recent studies have focused on the efficient production of PHA MCL in wild-type and recombinant microorganisms from abundant and cheap carbon sources, such as carbohydrates (6), fatty acids (7), or even polyethylene and aromatic compounds (8,9).…”

“…The resulting 3-hydroxyacyl-CoA precursors are polymerized to poly-3-hydroxyalkanoate (PHA MCL ) by PHA synthase PhaC1 P. putida (5). Synthesis of poly(3-hydroxybutyrate) [poly(3HB)] is deactivated by the deletion of phaC1 R. rubrum and phaC2 R. rubrum , which code for PHA SCL synthases (6). Additional carboxylases, which might be also involved in assimilating additional CO 2 (16), include a pyruvate synthase (Rru_A2398 [7]), a crotonyl-CoA reductase (Rru_A3063 [8]), a propionylCoA carboxylase (Rru_A1943 [9]), and a 2-oxoglutarate synthase (Rru_A2721 [10]).…”