Browsing by Author "Warner, P. J."
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Item Open Access Development of a disposable pyruvate biosensor to determine pungency in onions (Allium cepa L.)(Elsevier, 2006-05-15) Abayomi, Louise Anike; Terry, Leon A; White, S. F.; Warner, P. J.A disposable prototype pyruvate biosensor was constructed using pyruvate oxidase immobilised on mediated meldolas blue electrodes to determine pungency in onions (Allium cepa L.). The optimum operating potential was +150 mV (versus Ag/AgCl). A strong correlation between the biosensor response and untreated onion juice of known pyruvate concentration 2–12 μmol/g fresh weight (FW) was demonstrated. The biosensor was able to differentiate between low and high pungency onions. The detection limit using 1 unit of pyruvate oxidase was 1–2 μmol/g FW. Optimum concentrations of co-factors TPP, FAD and MgSO4 comprising the enzyme cocktail were determined as being 0.04, 0.1 and 30 mM, respectively.Item Open Access A genetic approach to improvements of Candida tropicalis as a biocatalyst(Cranfield University, 1990-11) Perry, Patricia Mair; Warner, P. J.It is well documented in the literature that, in addition to carbon sources such as glucose, Candida species are able to utilise a wide variety of n-alkanes which are degraded via beta-oxidation. Prior to beta-oxidation a primary oxidation system acts on the end terminal methyl groups to generate carboxyl groups. The main industrial aim of the work was to optimise the bioconversion of pelargonate [CH3(CH2)7COOH] to azeleate [HOOC(CH2)7COOH], i.e. the primary oxidation steps, by blocking the beta-oxidation pathway in C. tropicalis. To this end, a library of Sau 3AI partially digested C. tropicalis NCYC997 genomic DNA in pBR322 was constructed from which it was hoped to isolate and disrupt the long-chain fatty acid acyl-CoA oxidase genes, POX4 and POX5, which catalyse the first step of beta-oxidation. The library was probed with oligonucleotides specific to POX4 and POX5, and a putative POX4 clone was isolated.Item Open Access The microbial metabolism of, orth-di- and ortho-polyalkyl substituted aromatic hydrocarbons and the application of bacteria to the remediation of the natural environment(Cranfield University, 2002) Taylor , Frank; Warner, P. J.Abstract not available