Browsing by Author "Wolfram, James H."

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Bioprocessing of environmentally significant gases and vapors with gas-phase bioreactors
(1993-02) Apel, William A.; Dugan, Patrick R.; Wiebe, Michelle R.; Johnson, Earl G.; Wolfram, James H.; Rogers, Robert D.
Fixed thin film, gas/vapor phase bioreactors were assessed relative to their potential for the bioprocessing of methane, trichloroethylene (TCE), and p-xylene. Methanotrophic bacteria were used to process the methane and TCE while a xylene resistant strain of Pseudomonas putida was used to process the p-xylene. Comparisons between the gas phase bioreactors and conventional shaken cultures and sparged liquid bioreactors showed that the gas phase bioreactors offer advantages over the other two systems for the degradation of methane in air. Rates of methane removal with the gas phase bioreactors were 2.1 and 1.6 fold greater than those exhibited by the shaken cultures and sparged liquid bioreactors, respectively. The gas phase bioreactors were shown to have application for the removal of TCE vapors from air with a removal rate of approximately 9 μg TCE d-1 bioreactor-1. Xylene vapors were also scrubbed from air using gas phase bioreactors. At a feed rate of 140 μg of xylene min-1, approximately 46% of the xylene was mineralized to carbon dioxide in a single pass through a bench scale gas phase bioreactor.
Degradation of acetonitrile by pseudomonas aeruginosa
(1989-05) Nawaz, M. S.; Richardson, Andrew D.; Chapatwala, Kirit D.; Wolfram, James H.
Degradation of Acetonitrile by Pseudomonas putida
(1989-09) Nawaz, M. S.; Chapatwala, Kirit D.; Wolfram, James H.
A bacterium capable of utilizing high concentrations of acetonitrile as the sole source of carbon and nitrogen was isolated from soil and identified as Pseudomonas putida. This bacterium could also utilize butyronitrile, glutaronitrile, isobutyronitrile, methacrylonitrile, propionitrile, succinonitrile, valeronitrile, and some of their corresponding amides, such as acetamide, butyramide, isobutyramide, methacrylamide, propionamide, and succinamide as growth substrates. Acetonitrile-grown cells oxidized acetonitrile with a K(m) of 40.61 mM. Mass balance studies with [C]acetonitrile indicated that nearly 66% of carbon of acetonitrile was released as CO(2) and 14% was associated with the biomass. Metabolites of acetonitrile in the culture medium were acetic acid and ammonia. The acetate formed in the early stages of growth completely disappeared in the later stages. Cell extracts of acetonitrile-grown cells contained activities corresponding to nitrile hydratase and amidase, which mediate the breakdown of actonitrile into acetic acid and ammonia. Both enzymes were intracellular and inducible and hydrolyzed a wide range of substrates. The specific activity of amidase was at least 150-fold higher than the activity of the enzyme nitrile hydratase.
Degradation of organic cyanides by pseudomonas aeruginosa
(1991-03) Nawaz, M. S.; Davis, John W.; Wolfram, James H.; Chapatwala, Kirit D.
A bacterium capable of utilizing acetonitrile (methyl cyanide) as the sole source of carbon and nitrogen was isolated from soil and identified asPseudomonas aeruginosa. This bacterium could also utilize and oxidize numerous lower-mol-wt nitrile compounds and their corresponding amides as growth substrates. A metabolite of acetonitrile in the culture medium was determined to be ammonia. The accumulation of ammonia in the culture medium was proportional to the concentration of the substrate and the inoculum. Cell extracts of the bacterium contained activities corresponding to nitrile aminohydrolase (E C 3.5.5.1) and amidase (E C 3.5.1.4), which regulate the degradation of acetonitrile. Both enzymes were inducible and hydrolyzed a wide range of substrates, and it was determined that the specific activity of amidase was far greater than the activity of nitrile aminohydrolase.
Engineering scale-up of in situ bioremediation processes: a review
(1995-09) Sturman, Paul J.; Stewart, Philip S.; Cunningham, Alfred B.; Bouwer, Edward J.; Wolfram, James H.
To be useful to field practitioners, advances in bioremediation research must be capable of being scaled up from the laboratory to the field. The phenomena which control the rate at which biodegradation proceeds are typically scale-dependent in nature. Failure to understand and account for scale-dependent variables, such as mass transport limitations, spatial heterogeneities and the presence of competing microorganisms, may inhibit the effectiveness of field-scale bioremediation designs. This paper reviews and evaluates the methods available for characterization of the processes effecting bioremediation at scales ranging from the laboratory to the field. Questions facing the field-scale practitioner of bioremediation are addressed in a manner which highlights the current state of research, the reliability of results and the extent to which laboratory-scale research accurately reflects common field conditions. Where gaps or inadequacies exist in our current knowledge or methods, research needs are identified. This review is intended to complement existing work by providing a framework from which to assess the importance of scale of observation to a particular result or conclusion, thereby providing an integrated approach to the scale-up process.
Evidence of microbially influenced corrosion of boral used in spent fuel canisters
(1991) Wolfram, James H.; Miller, R. L.; Rogers, Robert D.
Microbial processing of volatile organics in industrial waste streams
(1992) Wolfram, James H.; Rogers, Robert D.; Higdem, D. M.
A strain of Pseudomonas putida has been isolated which tolerates and metabolizes toluene and p‐xylene. In our laboratory, this isolate has undergone selection and adaptation and presently is able to grow under a layer of 100% p‐xylene. From batch studies the initial rates of degradation are 1–3 mg/min/L. This strain of P. putida also tolerates the presence of a nonionic surfactant while still maintaining its metabolic activity. Preliminary testing using this isolate under chemostat conditions indicates that the potential for developing a bioprocess to treat these waste solvents may be possible.
Scale-up implications of respirometrically determined microbial kinetics parameters
(1994) Sturman, Paul J.; Sharp, Robert R.; DeBar, J. B.; Stewart, Philip S.; Cunningham, Alfred B.; Wolfram, James H.
Screening of encapsulated microbial cells for the degradation of inorganic cyanides
(1993-02) Chapatwala, Kirit D.; Babu, G. R. V.; Wolfram, James H.
Different encapsulation matrices were screened to encapsulate cells ofPseudomonas putida for degradation of inorganic cyanides. Degradation of NaCN by free cells and cells immobilized in agar, alginate or carrageenan matrices was studied. The rate of NaCN degradation was monitored for 120 h by measuring pH, bacterial growth, dissolved and gaseous NH3 and gaseous CO2. Alginate-immobilized cells degraded NaCN more efficiently than free cells or agar- or carrageenan-immobilized cells.