Does Addition of Phosphate and Ammonium Nutrients Affect Microbial Activity in Froth Treatment Affected Tailings?

We examined greenhouse gas (GHG) production upon the addition of ammonium and phosphate to mature fine tailing (MFT) samples from Alberta's Pond 2/3 (at 5 and 15 m) and Pond 7 (12.5 m) in microcosm studies. The methane production rate in unamended Pond 2/3 MFT correlated with sample age; the production rate was higher in the less dense, more recently discharged MFT samples and lower in the denser, deeper sample.

Manipulating the structure of medium-chain-length polyhydroxyalkanoate (MCL-PHA) to enhance thermal properties and crystallization kinetics.

We investigated the effects of the structure of medium-chain-length polyhydroxyalkanoates (MCL-PHAs) on their thermal properties and crystallization kinetics. The predominantly homopolymeric poly(3-hydroxydecanoate), P(3HD)-98, and the poly(3-hydroxydodecanoate), P(3HDD), exhibited sharp crystallization peaks upon cooling, with the latter exhibiting faster crystallization rates. A chemical modification strategy involving reaction with dicumyl peroxide and triallyl trimesate coagent was implemented to introduce branching and enhance the crystallization kinetics of P(3HD-98).

Biodegradation of CuTETA, an effluent by-product in mineral processing.

Polyamines such as triethylenetetramine (TETA) and other amine chelators are used in mineral processing applications. Formation of heavy metal complexes of these reagents as a by-product in effluent water is a recent environmental concern. In this study, Paecilomyces sp.

Stabilization and characterization of carboxylated medium-chain-length poly(3-hydroxyalkanoate) nanosuspensions.

The effects of carboxylation (via mercaptoundecanoic acid) on colloidal properties of medium-chain-length poly(3-hydroxyalkanoate) (mcl-PHA) latexes were studied. Non-ionic surfactants tested at 0.4% solids of 11 mol% carboxylated mcl-PHA produced similar particle sizes and particle size distribution (PdI) with Triton X-100 giving the smallest size.

Potential for mcl-PHA production from nonanoic and azelaic acids.

Greater than 65% of canola and high-oleic soy oil fatty acids is oleic acid, which is readily converted to nonanoic (NA) and azelaic (AzA) acids by ozonolysis. NA is an excellent substrate for medium-chain-length polyhydroxyalkanoate (mcl-PHA) production but AzA has few uses. Pseudomonas citronellolis DSM 50332 and Pseudomonas fluorescens ATCC 17400, both able to produce mcl-PHA from fatty acids and to grow on AzA as the sole source of carbon and energy, were assessed for the accumulation of mcl-PHA from AzA and NA.

Overproduction of MCL-PHA with high 3-hydroxydecanoate Content.

Methods of producing medium-chain-length poly-3-hydroxyalkanoate (mcl-PHA) with high content of the dominant subunit, 3-hydroxydecanoate (HD), were examined with an emphasis on a high yield of polymer from decanoic acid. High HD content was achieved by using a β-oxidation knockout mutant of Pseudomonas putida KT2440 (designated as P. putida DBA-F1) or by inhibiting β-oxidation with addition of acrylic acid (Aa) to wild type P.

Biodegradation and detoxification of naphthenic acids in oil sands process affected waters.

After oil sands process affected water (OSPW) was treated in a continuous flow biofilm reactor, about 40% of the organic compounds in the acid extractable fraction (AEF) including naphthenic acids (NAs) were degraded resulting in a reduction of 73% in the Microtox acute toxicity and of 22% in the yeast estrogenic assay. Using effect directed analysis, treated and untreated OSPW were fractionated by solid phase extraction and the fractions with the largest decrease in toxicity and estrogenicity were selected for analysis by electrospray ionization combined with linear ion trap and a high-resolution Orbitrap mass spectrometer (negative ion mode). The aim of this study was to determine whether compositional changes between the untreated and treated fractions provide insight related to biodegradation and detoxification of NAs.

Fed-batch production of poly-3-hydroxydecanoate from decanoic acid.

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.

Biodegradation of naphthenic acid surrogates by axenic cultures.

This is the first study to report that bacteria from the genera Ochrobactrum, Brevundimonas and Bacillus can be isolated by growth on naphthenic acids (NAs) extracted from oil sands process water (OSPW). These pure cultures were screened for their ability to use a range of aliphatic, cyclic and aromatic NA surrogates in 96-well microtiter plates using water-soluble tetrazolium redox dyes (Biolog Redox Dye H) as the indicator of metabolic activity. Of the three cultures, Ochrobactrum showed most metabolic activity on the widest range of NA surrogates.

Identification of estrogenic compounds in oil sands process waters by effect directed analysis.

Using effect directed analysis, the presence of estrogenic components in untreated and biologically treated oil sands process water (OSPW) was detected with the yeast estrogenic screening assay after fractionation with solid phase extraction followed by reversed phase high performance liquid chromatography. Comparison of the composition, as determined by electrospray ionization combined with high-resolution linear trap quadropole (LTQ)-Orbitrap Velos Pro hybrid mass spectrometry (negative ion) of selected estrogenic and nonestrogenic fractions identified compounds that were uniquely present in the estrogenic samples, biologically treated and untreated. Of the 30 most abundant compounds, there were 14 possible nonaromatic structures and 16 possible aromatic structures.

Biodegradation of naphthenic acids in oils sands process waters in an immobilized soil/sediment bioreactor.

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

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.

Fed-batch production of MCL-PHA with elevated 3-hydroxynonanoate content.

With no inhibition of β-oxidation, Pseudomonas putida KT2440 produces medium-chain-length poly(3-hydroxyalkanoate) (MCL-PHA) with approximately 65 mol% 3-hydroxynonanoate (HN) from nonanoic acid. Production of PHA with higher HN content and an adjustable monomeric composition was obtained using acrylic acid, a fatty acid β-oxidation inhibitor, together with nonanoic acid and glucose as co-substrates in fed-batch fermentations. Different monomeric compositions were obtained by varying the feeding conditions to impose different specific growth rates and inhibitor feed concentrations.

Biosynthesis and properties of medium-chain-length polyhydroxyalkanoates with enriched content of the dominant monomer.

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 %.

Biodegradation of 1,4-dioxane by a Flavobacterium.

A dioxane-degrading consortium was enriched from soil obtained from a contaminated groundwater plume. The enriched consortium did not use dioxane as the sole source of carbon and energy but co-metabolized dioxane in the presence of tetrahydrofuran (THF). THF and dioxane concentrations up to 1000 ppm were degraded by the enriched consortium in about 2 weeks with a longer lag phase observable at 1000 ppm.

Use of allylthiourea to produce soluble methane monooxygenase in the presence of copper.

Methanotrophs expressing soluble methane monooxygenase (sMMO) may find use in a variety of industrial applications. However, sMMO expression is strongly inhibited by copper, and the growth rate may be limited by the aqueous solubility of methane. In this study, addition of allylthiourea decreased intracellular copper in Methylosinus trichosporium OB3b, allowing sMMO production at Cu/biomass ratios normally not permitting sMMO synthesis.

Fed-batch production of unsaturated medium-chain-length polyhydroxyalkanoates with controlled composition by Pseudomonas putida KT2440.

Unsaturated medium-chain-length polyhydroxyalkanoates (MCL-PHA) were produced at a productivity of 0.63-1.09 g PHA l(-1) h(-1) with final PHA content ranging from 42.

Production of soluble methane monooxygenase during growth of Methylosinus trichosporium on methanol.

Soluble methane monooxygenase (sMMO) can degrade many chlorinated and aromatic pollutants. It is produced by certain methanotrophs such as Methylosinus trichosporium when grown on methane under copper limitation but, due to its low aqueous solubility, methane cannot support dense biomass growth. Since it is water soluble, methanol may be a more attractive growth substrate, but it is widely believed that sMMO is not produced on methanol.

Fermentation process development for the production of medium-chain-length poly-3-hyroxyalkanoates.

This paper presents a review of the existing fermentation processes for the production of medium-chain-length poly-3-hydroxyalkanoates (MCL-PHAs). These biodegradable polymers are usually produced most efficiently from structurally related carbon sources such as alkanes and alkanoic acids. Unlike alkanoic acids, alkanes exhibit little toxicity but their low aqueous solubility limits their use in high density culture.

Increasing the yield of MCL-PHA from nonanoic acid by co-feeding glucose during the PHA accumulation stage in two-stage fed-batch fermentations of Pseudomonas putida KT2440.

A method was developed to increase the yield of MCL-PHA from nonanoic acid in the PHA accumulation phase. Pseudomonas putida KT2440 was grown on glucose until ammonium-limitation was imposed. In the second (accumulation) stage, either glucose, nonanoic acid, or a mixture of these carbon and energy sources was supplied.

Growth and laccase production kinetics of Trametes versicolor in a stirred tank reactor.

White rot fungi are a promising option to treat recalcitrant organic molecules, such as lignin, polycyclic aromatic hydrocarbons, and textile dyes, because of the lignin-modifying enzymes (LMEs) they secrete. Because knowledge of the kinetic parameters is important to better design and operate bioreactors to cultivate these fungi for degradation and/or to produce LME(s), these parameters were determined using Trametes versicolor ATCC 20869 (ATCC, American Type Culture Collection) in a magnetic stir bar reactor. A complete set of kinetic data has not been previously published for this culture.

Carbon-limited fed-batch production of medium-chain-length polyhydroxyalkanoates from nonanoic acid by Pseudomonas putida KT2440.

Pseudomonas putida KT2440 grew on glucose at a specific rate of 0.48 h(-1) but accumulated almost no poly-3-hydroxyalkanoates (PHA). Subsequent nitrogen limitation on nonanoic acid resulted in the accumulation of only 27% medium-chain-length PHA (MCL-PHA).

On-line estimation of dissolved methane concentration during methanotrophic fermentations.

Knowledge of the aqueous phase methane concentration is critical to understanding and controlling process kinetics in methanotrophic bioreactors. Unfortunately since no dissolved methane probe is commercially available, this data must be obtained off-line by the time-consuming gas-liquid partition method. In this study we demonstrate how knowledge of the reactor's k(L)a for oxygen combined with gas phase methane analysis can be used to continuously estimate the aqueous phase concentration of dissolved methane.

Acetone extraction of mcl-PHA from Pseudomonas putida KT2440.

A methodology was developed for the extraction of medium-chain-length poly-3-hydroxyalkanoates (mcl-PHA) from Pseudomonas putida. It was determined that if dry P. putida biomass containing mcl-PHA was washed in 20 volumes of methanol for 5 min followed by Soxhlet extraction in 10 volumes of acetone for 5 h, almost all of the PHA could be recovered with no detectable loss of molecular weight.