A feeding strategy for incorporation of canola derived medium-chain-length monomers into the PHA produced by wild-type Cupriavidus necator

Abstract

The aim of this study was to increase the density of wild type Cupriavidus necator H16 biomass grown on fructose in order to produce sufficient copolymer of short-chain-length (scl) and medium-chain-length (mcl) polyhydroxyalkanoate (PHA) from canola oil for mechanical testing of the PHA. Initial batch cultivation on fructose was followed by exponential feeding of fructose at a predetermined μ to achieve 44.4 g biomass/l containing only 20 % w/w of polyhydroxybutyrate (PHB) with a Y(x/fructose) of 0.44 g/g. In a third stage, canola oil was added under N-limited conditions to produce 92 g/l of biomass with 48 % w/w scl-mcl PHA. Using known standards, the PHA composition was confirmed by GC-MS analysis as 99.81 % 3-hydroxybutyrate, 0.06 % 3-hydroxyvalerate, 0.09 % 3-hydroxyhexanoate and 0.04 % 3-hydroxyoctanoate. The melting temperature (179 °C), crystallinity (54 %), tensile stress (25.1 Mpa) and Young's modulus (698 Mpa) for a PHB standard decreased to 176 °C, 52 %, 19.1 and 443 Mpa respectively for C. necator PHA produced in the 3-stage process.

Valorization of fatty acids-containing wastes and byproducts into short- and medium-chain length polyhydroxyalkanoates

“…C. necator has a Type I synthase, thus it is only able to synthesize 3HB and 3-hydroxyvalerate (3HV) monomers. Recently, Rathinasabapathy et al [30] and Ló pez-Cuellar et al [31] reported on the production of a mcl-PHA copolymer by C. necator, when canola oil was used as sole carbon source. However, in the present study, the fatty acids present in UCO, OOD and FAB (Table 2) were used neither as 3HV precursors nor for mcl-PHA monomer production.…”

Synthesis of Poly-(R-hydroxyalkanoates) byCupriavidus necatorATCC 17699 Using Mexican Avocado(Persea americana)Oil as a Carbon Source

“…Conversely, Du et al [42] achieved the production of PHBV using fatty acids from food scraps, whereas Dennis et al [18] demonstrated that the C. necator synthase could accept C6 substrates (Table 3). A few studies have also identified larger monomeric units when using vegetable oils as carbon sources [6,21].…”

“…The ability of C. necator to synthesize PHB and PHBV, as well as other PHAs, has been previously reported [6,20,21]. The limiting productions costs had led to proposals for the use of cheaper carbon sources, such as organic debris, wastewater, or even vegetable oils [22].…”

PRODUCTION OF MEDIUM CHAIN LENGTH POLYHYDROXYALKANOATES FROM Cupriavidus necator WITH BEESWAX HYDROLYZATES AS CARBON SOURCE

“…Several studies have evaluated various renewable carbon sources, such as canola oil (Rathinasabapathy et al 2013) and used cooking oil, which have demonstrated great biotechnological potential for the production of mcl-PHA (Cruz et al 2015). During the biosynthesis of PHA by Cupriavidus necator (formerly Wautersia eutropha > Ralstonia eutropha > Alcaligenes eutrophus) from fatty acids, López-Cuéllar et al (2011), Rathinasabapathy et al (2013) and Inomata et al (2014) demonstrated that C. necator was able to synthesize mcl-PHA using fructose and canola oil as substrates in a three stages fed-batch system, although it has been reported that the PHA synthase of C. necator is strictly specific for scl-PHA monomers (Slater et al 1992).…”

“…During the biosynthesis of PHA by Cupriavidus necator (formerly Wautersia eutropha > Ralstonia eutropha > Alcaligenes eutrophus) from fatty acids, López-Cuéllar et al (2011), Rathinasabapathy et al (2013) and Inomata et al (2014) demonstrated that C. necator was able to synthesize mcl-PHA using fructose and canola oil as substrates in a three stages fed-batch system, although it has been reported that the PHA synthase of C. necator is strictly specific for scl-PHA monomers (Slater et al 1992).…”