Preliminary assessment of the odour impact model as a regulatory strategy.

Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1986 .N534. Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.A.Sc.)--University of Windsor (Canada), 1986

Comparison of two agricultural wastes for phenol removal via peroxidase-catalyzed enzymatic approach

© The Authors, published by EDP Sciences, 2016. Agricultural wastes of jicama and luffa skin peels were used as the source for peroxidase extraction. The extracted crude enzymes showed similar activities, 1.34U/mL and 1.22U/mL for jicama and luffa peroxidase respectively. These peroxidases were used to treat phenol under varying operating conditions of buffer pH, hydrogen peroxide concentration, enzyme volume and temperature. Jicama peroxidase demonstrated a phenol removal efficiency of approximately 90% at buffer pH 7, 1mM hydrogen peroxide using 1.5mL enzyme at 25°C. Luffa peroxidase required a higher dosage of hydrogen peroxide, and exhibited a removal efficiency of 84% at 8mM with other operating conditions same as jicama peroxidase. Jicama peroxidase is sensitive to pH change and more susceptible to thermal denaturation. Luffa peroxidase showed a better stability in terms of temperature

Enzyme-catalyzed polymerization and precipitation of aromatic compounds from wastewater.

Horseradish peroxidase (HRP) demonstrates a valuable potential for wastewater treatment by catalyzing the polymerization and precipitation of aromatic compounds from water. It acts on a broad range of compounds including those that are biorefractory or toxic to microbes and retains its catalytic ability over wide ranges of temperature, pH, and contaminant concentration. Removal efficiency is dependent on the nature of the aromatic substrate and the dose of enzyme used. Optimal catalytic lifetime was achieved in the pH range of 7 to 9 for the eight phenolic compounds used in this study. Enzymatic precipitation should be conducted at temperatures below 35\sp\circC to prevent significant thermal inactivation of peroxidase. The stoichiometry of the reaction between aromatic compound and hydrogen peroxide was unity. Enhanced removal of hard-to-remove compounds was accomplished by co-precipitation with other substrates of HRP. A kinetic model was developed which matches the trends of data collected in a batch reactor under various conditions of enzyme, aromatic substrate and peroxide concentrations. Further development is required to define the mechanisms and kinetics of inactivation to extend application of the model to the design of a full-scale waste treatment system. The catalytic lifetime of the enzyme may be extended by maintaining a low instantaneous enzyme concentration in the reaction mixture. The enzyme catalyzed polymerization process was implemented in a continuous stirred tank reactor (CSTR) configuration because reactant and enzyme concentrations are lowered immediately upon entering the reactor causing a reduction in free radical inactivation and Compound III formation. Catalytic turnovers achieved in single and multiple CSTR\u27s in series were significantly higher than those observed in batch reactors when sufficient retention time was provided.Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1991 .N578. Source: Dissertation Abstracts International, Volume: 53-09, Section: B, page: 4923. Supervisors: J. K. Bewtra; K. E. Taylor. Thesis (Ph.D.)--University of Windsor (Canada), 1991

Multienzyme Immobilized Polymeric Membrane Reactor for the Transformation of a Lignin Model Compound

We have developed an integrated, multienzyme functionalized membrane reactor for bioconversion of a lignin model compound involving enzymatic catalysis. The membrane bioreactors were fabricated through the layer-by-layer assembly approach to immobilize three different enzymes (glucose oxidase, peroxidase and laccase) into pH-responsive membranes. This novel membrane reactor couples the in situ generation of hydrogen peroxide (by glucose oxidase) to oxidative conversion of a lignin model compound, guaiacylglycerol-β-guaiacyl ether (GGE). Preliminary investigation of the efficacy of these functional membranes towards GGE degradation is demonstrated under convective flow mode. Over 90% of the initial feed could be degraded with the multienzyme immobilized membranes at a residence time of approximately 22 s. GGE conversion product analysis revealed the formation of oligomeric oxidation products upon reaction with peroxidase, which may be a potential hazard to membrane bioreactors. These oxidation products could further be degraded by laccase enzymes in the multienzymatic membranes, explaining the potential of multi enzyme membrane reactors. The multienzyme incorporated membrane reactors were active for more than 30 days of storage time at 4 °C. During this time span, repetitive use of the membrane reactor was demonstrated involving 5–6 h of operation time for each cycle. The membrane reactor displayed encouraging performance, losing only 12% of its initial activity after multiple cycles of operation

Detection and Classification of Human Body Odor Using an Electronic Nose

An electronic nose (E-nose) has been designed and equipped with software that can detect and classify human armpit body odor. An array of metal oxide sensors was used for detecting volatile organic compounds. The measurement circuit employs a voltage divider resistor to measure the sensitivity of each sensor. This E-nose was controlled by in-house developed software through a portable USB data acquisition card with a principle component analysis (PCA) algorithm implemented for pattern recognition and classification. Because gas sensor sensitivity in the detection of armpit odor samples is affected by humidity, we propose a new method and algorithms combining hardware/software for the correction of the humidity noise. After the humidity correction, the E-nose showed the capability of detecting human body odor and distinguishing the body odors from two persons in a relative manner. The E-nose is still able to recognize people, even after application of deodorant. In conclusion, this is the first report of the application of an E-nose for armpit odor recognition

Horseradish and soybean peroxidases: comparable tools for alternative niches?

Horseradish and soybean peroxidases (HRP and SBP, respectively) are useful biotechnological tools. HRP is often termed the classical plant heme peroxidase and although it has been studied for decades, our understanding has deepened since its cloning and subsequent expression, enabling numerous mutational and protein engineering studies. SBP, however, has been neglected until recently, despite offering a real alternative to HRP: SBP actually outperforms HRP in terms of stability and is now used in numerous biotechnological applications, including biosensors. Review of both is timely. This article summarizes and discusses the main insights into the structure and mechanism of HRP, with special emphasis on HRP mutagenesis, and outlines its use in a variety of applications. It also reviews the current knowledge and applications to date of SBP, particularly biosensors. The final paragraphs speculate on the future of plant heme-based peroxidases, with probable trends outlined and explored

Realization and Properties of Biochemical-Computing Biocatalytic XOR Gate Based on Enzyme Inhibition by a Substrate

We consider a realization of the XOR logic gate in a process biocatalyzed by an enzyme (here horseradish peroxidase: HRP), the function of which can be inhibited by a substrate (hydrogen peroxide for HRP), when the latter is inputted at large enough concentrations. A model is developed for describing such systems in an approach suitable for evaluation of the analog noise amplification properties of the gate. The obtained data are fitted for gate quality evaluation within the developed model, and we discuss aspects of devising XOR gates for functioning in "biocomputing" systems utilizing biomolecules for information processing