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Aspergillus niger and Penicillium candidum were grown and harvested on days 6 and 8, which corresponded to their maximal biomasses and lipoxygenase (LOX) activities. The extracts were enriched with ammonium sulfate precipitation at 30 to 70% and 20 to 60% of saturation, respectively. The LOX activity was assayed with linoleic, linolenic and arachidonic acids as substrates. Both enriched microbial LOXs demonstrated preferential substrate specificities towards free fatty acids, over acyl esters of linoleic acid. The LOXs had the highest catalytic efficiency values (ratio of V max to Km) for linolenic acid biocatalysis. Major and minor pH optima at 5.0 and 10.5 were observed for A. niger, whereas for P. candidum they were at 6.0 and 8.5. Normal phase high-performance liquid chromatography (NP-HPLC) and gas-liquid chromatography/mass spectrometry (GC/MS) characterization of end products revealed that both LOXs produced the 10-hydroperoxide of linoleic acid (10-HPOD) at 15 to 16% of total isomers detected, respectively. Chiral studies of the P. candidum LOX catalyzed hydroperoxides revealed an excess in the production of (S) stereo-isomers resultant from linoleic, linolenic and arachidonic acids bioconversion. Penicillium camemberti was grown and harvested at its maximal biomass and LOX activity. The microbial extract was ultrafiltered (30 kDa NMWCO) and KCI (7.5 ppm) was added prior to lyophilization for the stabilization of enzyme activity. The LOX and hydroperoxide lyase (HPL) activities were assayed using linoleic acid and the 10-HPOD as substrates, respectively. The post-lyophilization residual activities were 93% and 223% for LOX and HPL, respectively. The long-term storage stability (-80°C) of the extract (KCI 7.5 ppm) was ~100% after 8 and 4 weeks for LOX and HPL, respectively. The investigated stabilizing chemical additives included glycine, mannitol, glycerol, sucrose and polyethylene glycol. The lowest Kinactivation values were observed with glycine with 0.136 and 0.0296 for LOX and HPL, respectively. Thermostability studies indicated that 5 and 10% (w/v) mannitol and glycine effectively stabilized LOX and HPL, respectively. Immobilization of an enzymatic extract from P. camemberti containing LOX and HPL activities was performed on EupergitRTMC and EupergitRTMC250L-iminodiacetate (IDA), respectively. The free and immobilized extracts both possessed LOX activity with a pH optimum of 6.0, whereas pH 6.0 and 4.0 were the optima of the HPL activity for free and immobilized extract, respectively. Optimal LOX reaction temperatures were 30 and 55°C for the free and immobilized extract, respectively, whereas 45 and 30°C were determined for the HPL activity of the free and immobilized extract, respectively. Long-term stability (-80°C) of the immobilized extract containing LOX and HPL activity showed residual activities of 82.6 and 93.8% after 4 and 8 weeks, respectively.

Zugl.: Braunschweig, Techn. Univ., Diss., 2008

Thesis (Ph.D.)--University of Wyoming, 2008. / Title from PDF title page (viewed on Mar. 23, 2010). Includes bibliographical references.

Zugl.: Bayreuth, Univ., Diss., 2006

Thesis (M.A.)--Carleton University, 1992. / Also available in electronic format on the Internet.

Techn. University, Diss., 1998--Braunschweig.

Thesis (M.A.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Boston University. University Professors Program Senior theses. / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / 2031-01-02

o setor vitivinícola é responsável por 1% do Produto Interno Bruto (PIB) do Rio Grande do Sul, sendo o estado responsável por 90% da produção Brasileira de vinhos, cujo mercado é crescente. Na indústria vitícola cerca de 25% da quantidade processada de uva transforma-se em resíduos, representados principalmente por cascas, sementes e engaço. Este trabalho teve como objetivo analisar as características nutricionais de bagaço de Vitis sp e o seu enriquecimento com Aspergillus niger T0005/007-2. Foi verificado que a fermentação em estado sólido destes resíduos utilizando o fungo filamentoso A. niger eleva os teores de . proteína bruta de resíduos de uva, além do aumento do valor calórico, de carboidratos, fibra alimentar total, lipídios, e umidade. O incremento dos carboidratos 20 dias após a exposição ao fungo A. niger é um fator favorável para utilização do mesmo para ração animal, pois desta forma se torna a formulação mais adequada para uma complementação à ração de suínos. O crescimento de micélio do fungo A. niger, sobre resíduos de engaço de Vitis sp mostra-se promissor para o aumento do valor nutricional dos resíduos da produção de uva, que já vêm sendo utilizados na alimentação de alguns animais. Com base nesses resultados, a bioconversão do engaço da uva empregando fermentação em estado sólido com linhagens de A. niger pode ser um complemento para alimentação de animais (sic). / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2017-11-24T18:16:05Z No. of bitstreams: 1 Dissertacao Edmar Sganzerla.pdf: 16247252 bytes, checksum: 2a586b7329e98b4d5fcfd69172ad5046 (MD5) / Made available in DSpace on 2017-11-24T18:16:05Z (GMT). No. of bitstreams: 1 Dissertacao Edmar Sganzerla.pdf: 16247252 bytes, checksum: 2a586b7329e98b4d5fcfd69172ad5046 (MD5) Previous issue date: 2017-11-24 / The wine sector is responsible by 1% ofthe Gross Domestic Product (GDP) of Rio Grande do Sul, being the state responsible by 90% of the brazilian production of wines, which market is growing. In the wine industry, around 25% of the processed amount of grape turn's into waste, mainly represented by grape skins, seeds and stems. This work had the objective of analyzing the nutritional characteristics of Vitis sp stem's and its improvement with Aspergillus niger T0005/007-2. It was checked that the solid state fermentation of those wastes using the filamentous fungus A. niger increases the crude protein content of grape waste, besides the caloric value risement, of carbohydrates, total dietary fiber, lipids and moisture. The increment of the carbohydrates 20 days afier the exposition to the fungus A. niger is a favorable facto r to the usage for animal food, because in this way, the formulation it can be added to a swine's feed complementation. The implementation of fungus A. niger, into stem's Vitis sp wastes seems promissing to the nutritional value agregation over wastes of grape production that are already being used into the feed of some animals. Based on these results, the grape's stem bioconversion using the solid state fermentation method could be an alternative at animal's feeding (sic).