Vaughan, Canada
Vaughan, Canada

Time filter

Source Type

Ramsay B.A.,Polyferm Canada Inc.
Macromolecular Materials and Engineering | Year: 2014

Poly(lactic acid) (PLA) is chemically modified by radical mediated solvent-free, peroxide-initiated grafting of triallyl trimesate (TAM) coagent in the melt state. When compared with the parent material and with PLA samples treated with peroxide alone, coagent-modified materials demonstrate higher molar mass and improved melt rheological properties, including substantial improvements in melt elasticity and strain hardening under uniaxial extension. Although similar rheological modifications are obtained by PLA chain extension using a multi-functional epoxide oligomeric chain extender, the coagent-modified material demonstrates significantly enhanced crystallinity and crystallization rates. The appearance of a distinct crystallization exothermic peak and the disappearance of the cold crystallization temperature point to a nucleation effect in the coagent modified PLA, which together with the rheological enhancements can promote the processability of this material in conventional thermoplastics operations. © 2014 WILEY-VCH Verlag GmbH & Co.


Nerkar M.,Queen's University | Ramsay J.A.,Queen's University | Ramsay B.A.,Polyferm Canada Inc. | Kontopoulou M.,Queen's University | Hutchinson R.A.,Queen's University
Journal of Polymers and the Environment | Year: 2013

Absolute molecular weight distributions were determined for different medium-chain-length poly(3-hydroxyalkanoates) (MCL PHAs) with predominantly 3-hydroxyoctanoate (PHO), 3-hydroxynonanoate (PHN) or 3-hydroxydodecanoate content. This is the first study to estimate the Mark-Houwink constants of these polymers in the commonly employed GPC carrier solvent tetrahydrofuran (THF). The absolute molecular weight averages were determined via triple-detector size exclusion chromatography and combined with analyses using various detectors. Unlike with the short-chain-length poly(3-hydroxybutyrate), PHB, uncorrected polystyrene calibration in THF provided a good estimate (within 10 %) of absolute MW values for these MCL PHAs, irrespective of side chain length. Weight-average MW values ranged from 172,000 Da for PHO to 18,200 for PHN with 30 mol% 3-hydroxyheptanoate, and dispersities of all samples were close to two. Melt viscosity data suggested an entanglement molecular weight around 8 × 104 Da, significantly higher than most polymers. © 2012 Springer Science+Business Media, LLC.


Rathinasabapathy A.,Queen's University | Rathinasabapathy A.,CINVESTAV | Ramsay B.A.,Polyferm Canada Inc. | Ramsay J.A.,Queen's University | Perez-Guevara F.,CINVESTAV
World Journal of Microbiology and Biotechnology | Year: 2014

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 Yx/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. © 2013 Springer Science+Business Media Dordrecht.


Nerkar M.,Queen's University | Ramsay J.A.,Queen's University | Ramsay B.A.,Polyferm Canada Inc. | Kontopoulou M.,Queen's University
Journal of Polymers and the Environment | Year: 2014

Blends of poly-3-hydroxybutyrate with an elastomeric medium-chain-length poly-3-hydroxyalkanoate (MCL-PHA), containing 98 mol% 3-hydroxyoctanoate and 2 mol% 3-hydroxyhexanoate (referred to as PHO), were prepared by melt compounding. Coarsening of the droplet-matrix morphology of the blends was noted as the PHO content increased beyond 5 wt%; this was attributed to the significant viscosity mismatch between the components. Addition of PHO improved the thermal stability of the blends, reduced their crystallinity and resulted in shifts in their melting and crystallization temperatures. The blends had improved tensile strain at break. The unnotched impact strength showed a threefold increase at 30 wt% PHO content. Cross-linking of PHO using a peroxide initiator increased its viscosity, thus improving the morphology and mechanical properties of the blends. © 2013 Springer Science+Business Media New York.


Gao J.,Queen's University | Ramsay J.A.,Queen's University | Ramsay B.A.,Queen's University | Ramsay B.A.,Polyferm Canada Inc.
Journal of Biotechnology | Year: 2016

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 0.15h-1. This method produced a maximum of 39gL-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 75gL-1 biomass containing 74% PHA and an overall PHA productivity of 1.16gL-1h-1 with the production of each gram of PHA requiring only 1.16g of decanoic acid. The final PHA composition (on a molar basis) was 78% 3-hydroxydecanoate, 11% 3-hydroxyoctanoate and 11% 3-hydroxyhexanoate. © 2015 Elsevier B.V.


McKenzie N.,Queen's University | Yue S.,Queen's University | Liu X.,Queen's University | Ramsay B.A.,Polyferm Canada Inc. | Ramsay J.A.,Queen's University
Chemosphere | Year: 2014

Aqueous extraction of bitumen in the Alberta oil sands industry produces large volumes of oil sands process water (OSPW) containing naphthenic acids (NAs), a complex mixture of carboxylic acids that are acutely toxic to aquatic organisms. Although aerobic biodegradation reduces NA concentrations and OSPW toxicity, treatment times are long, however, immobilized cell reactors have the potential to improve NA removal rates. In this study, two immobilized soil/sediment bioreactors (ISBRs) operating in series were evaluated for treatment of NAs in OSPW. A biofilm was established from microorganisms associated with sediment particles from an OSPW contaminated wetland on a non-woven textile. At 16months of continuous operation with OSPW as the sole source of carbon and energy, 38±7% NA removal was consistently achieved at a residence time of 160h at a removal rate of 2.32mgNAsL-1d-1. The change in NA profile measured by gas chromatography-mass spectrometry indicated that biodegradability decreased with increasing cyclicity. These results indicate that such treatment can significantly reduce NA removal rates compared to most studies, and the treatment of native process water in a bioreactor has been demonstrated. Amplification of bacterial 16S rRNA genes and sequencing using Ion Torrent sequencing characterized the reactors' biofilm populations and found as many as 235 and 198 distinct genera in the first and second bioreactor, respectively, with significant populations of ammonium- and nitrite-oxidizers. © 2014 Elsevier Ltd.


Vo M.T.,Kingston University | Ko K.,Kingston University | Ramsay B.,Kingston University | Ramsay B.,Polyferm Canada Inc.
Journal of Industrial Microbiology and Biotechnology | Year: 2015

A medium-chain-length poly-3-hydroxyalkanote (MCL-PHA) depolymerase knockout mutant of Pseudomonas putida KT2440 was produced by double homologous recombination. A carbon-limited shake-flask study confirmed that depolymerase activity was eliminated. Lysis of both mutant and wild-type strains occurred under these conditions. In carbon-limited, fed-batch culture, the yield of unsaturated monomers from unsaturated substrate averaged only 0.62 mol mol−1 for the phaZ minus strain compared to 0.72 mol mol−1 for the wild type. The mutant strain also produced more CO2 and less residual biomass from the same amount of carbon substrate. However, most results indicated that elimination of PHA depolymerase activity had little impact on the overall yield of biomass and PHA. © 2015, Society for Industrial Microbiology and Biotechnology.


Nerkar M.,Queen's University | Ramsay B.,Polyferm Canada Inc.
Annual Technical Conference - ANTEC, Conference Proceedings | Year: 2014

Poly(lactic acid) (PLA) was reactively modified by using a multifunctional co-agent (triallyl trimesate) in the presence of dicumyl peroxide. The viscosity, elasticity and melt strength of PLA increased substantially following reactive compounding. Furthermore, the rate of crystallization of co-agent in modified PLA was significantly higher than that of the pristine PLA and a distinct crystallization peak appeared. Reactively modified blends of PLA with an elastomeric polyhydroxyoctanoate exhibited similar features, and significant improvements in blend morphology. Copyright © (2014) by the Society of Plastics Engineers.


Jiang X.,Queen's University | Sun Z.,McGill University | Marchessault R.H.,McGill University | Ramsay J.A.,Queen's University | Ramsay B.A.,Polyferm Canada Inc.
Biomacromolecules | Year: 2012

When grown in a nonanoic acid-limited chemostat at a dilution rate of 0.25 h-1, Pseudomonas putida KT2440 produced poly(3-hydroxynonanoate-co-3- hydroxyheptanoate) containing 68 mol % 3-hydroxynonanoate (C9) and 32 mol % 3-hydroxyheptanoate (C7). Under the same conditions, but in the presence of acrylic acid, a fatty acid β-oxidation inhibitor, the C9 monomer content increased to 88 mol %. Cofeeding glucose (3.9 g L-1) and nonanoic acid (2.9 ± 0.1 g L-1) in continuous culture with 0.2 g L -1 of acrylic acid in the feed, further increased the C9 content to 95 mol %. A yield of PHA from nonanoic acid of 0.93 mol mol-1 was attained. PHA with a 3-hydroxyoctanoate (C8) content of 98 mol % was produced with the same cofeeding methodology from octanoic acid. As the dominant monomer content increased, the melting point of the poly(3-hydroxynonanoate) copolymers increased from 46 to 63 °C and that of the poly(3-hydroxyoctanoate) copolymers from 54 to 62 °C. All copolymer compositions resulted in elongation to break values of about 1300%, but tensile strength at break and Young's modulus both increased with increasing amounts of the dominant monomer. © 2012 American Chemical Society.


PubMed | Polyferm Canada Inc. and Queen's University
Type: | Journal: Journal of biotechnology | Year: 2016

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.

Loading Polyferm Canada Inc. collaborators
Loading Polyferm Canada Inc. collaborators