Benzaldehyde (BZA), a biologically derived high-value molecule used in the flavour and fragrance industry for its characteristic almond-like aroma, has also found use in nutraceutical, pharmaceutical, cosmetics, agrochemical, and dye applications. Although, nature-identical BZA is most commonly produced by chemical synthesis, biologically derived BZA, whether by plant material extraction or via microbial biocatalysts, commands much higher prices. The bioproduction of high value molecules has often been characterized by low titers as results of substrate and product inhibition. The current work examined a variety of process strategies and the implementation of a solid-liquid bioreactor partitioning system with continuous integrated pervaporation to enhance the bioproduction of BZA using Pichia pastoris. Previous work on two-phase partitioning bioreactors (TPPBs) for the biotransformation of BZA using Pichia pastoris has had limitations due to long fermentation times and unutilized substrate in the immiscible polymer phase, contributing to complications for product purification. To reduce fermentation times, a mixed methanol/glycerol feeding strategy was employed and reduced the time required for high-density fermentation by 3.5 fold over previous studies. Additionally, because BZA and not the substrate benzyl alcohol (BA) had been found to be significantly inhibitory to the biotransformation reaction, a polymer selection strategy based on the ratio of partition coefficients (PCs) for the two target molecules was implemented. Using the polymer Kraton D1102K, with a PC ratio of 14.9 (BZA:BA), generated a 3.4 fold increase in BZA produced (14.4 g vs. 4.2 g) relative to single phase operation at more than double the volumetric productivity (97 mg L-1 h-1 vs. 41 mg L-1 h-1). This work also confirmed that the solute(s) of interest were taken up by polymers via absorption, not adsorption. BZA and BA cell growth inhibition experiments showed that these compounds are toxic to cells and it was their accumulation rather than low enzyme levels or energy (ATP) depletion that caused a reduction in the biotransformation rate. For this reason, the final strategy employed to enhance the bioproduction of benzaldehyde involved in situ product removal by pervaporation using polymer (Hytrel 3078) fabricated into tubing by DuPont, Canada. This aspect was initiated by first characterizing the custom-fabricated tubing in terms BZA and BA fluxes. The tubing was then integrated into an in situ pervaporation biotransformation and was shown to be effective at continuous product separation, using 87.4% less polymer by mass in comparison to polymer beads in conventional TPPB operation, and improved overall volumetric productivity by 214% (245.9 mg L-1 h-1 vs. 115.0 mg L-1 h-1) over previous work producing BZA. / Thesis (Master, Chemical Engineering) -- Queen's University, 2013-09-28 17:41:45.458

R-phenylacetylcarbinol (PAC) is used as a precursor for production of ephedrine and pseudoephedrine, which are anti-asthmatics and nasal decongestants. PAC is produced from benzaldehyde and pyruvate mediated by pyruvate decarboxylase (PDC). A strain of Rhizopus javanicus was evaluated for its production of PDC. The morphology of R. javanicus was influenced by the degree of aeration/agitation. A relatively high specific PDC activity (328 U decarboxylase g-1 mycelium) was achieved when aeration/agitation were reduced significantly in the latter stages of cultivation. The stability of partially purified PDC and crude extract from R. javanicus were evaluated by examining the enzyme deactivation kinetic in various conditions. R. javanicus PDC was less stable than Candida utilis PDC currently used in our group. A kinetic model for the deactivation of partially purified PDC extracted from C. utilis by benzaldehyde (0?00 mM) in 2.5 M MOPS buffer has been developed. An initial lag period prior to deactivation was found to occur, with first order dependencies of PDC deactivation on exposure time and on benzaldehyde concentration. A mathematical model for the enzymatic biotransformation of PAC and its associated by-products has been developed using a schematic method devised by King and Altman (1956) for deriving the rate equations. The rate equations for substrates, product and by-products have been derived from the patterns for yeast PDC and combined with a deactivation model for PDC from C. utilis. Initial rate and biotransformation studies were applied to refine and validate a mathematical model for PAC production. The rate of PAC formation was directly proportional to the enzyme activity level up to 5.0 U carboligase ml-1. Michaelis-Menten kinetics were determined for the effect of pyruvate concentration on the reaction rate. The effect of benzaldehyde on the rate of PAC production followed the sigmoidal shape of the Monod-Wyman-Changeux (MWC) model. The biotransformation model, which also included a term for PDC inactivation by benzaldehyde, was used to determine the overall rate constants for the formation of PAC, acetaldehyde and acetoin. Implementation of digital pH control for PAC production in a well-stirred organic-aqueous two-phase biotransformation system with 20 mM MOPS and 2.5 M dipropylene glycol (DPG) in aqueous phase resulted in similar level of PAC production [1.01 M (151 g l-1) in an organic phase and 115 mM (17.2 g l-1) in an aqueous phase after 47 h] to the system with a more expensive 2.5 M MOPS buffer.

&amp / #945 / -Hydroxy phosphonates are versatile building blocks for the synthesis of many biologically active compounds that display antiviral, antibacterial, anticancer, pesticide activities beside their enzyme inhibitory activities such as they are the inhibitors of rennin or human immunodeficiency virus (HIV) protease and polymerase. Benzaldehyde lyase is able to catalyze not only C-C bond formation reactions but also C-C bond breaking reactions with high enantioselectivity that brings about the development of new synthetic methodologies for the synthesis of hydroxy ketones which are the key intermediates in the synthesis of many biologically active compounds due to the versatility of stereogenic center for developing structural diversity. There are several synthetic methodologies for the synthesis of hydroxy phoshonates however, in this work we have achieved the synthesis of hydroxy phoshonates through C-C bond forming reactions catalyzed by Benzaldehyde lyase that offers the use of green methodologies. Moreover, we have achieved the synthesis of hydroxy ketones which are versatile building blocks in the synthesis of many biologically active compounds via the immobilization of BAL enzyme on superparamagnetic solid support with high yield and high enantioselectivity.

Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2015-02-04T11:45:28Z No. of bitstreams: 2 Dissertação - Jaires Gomes de Oliveira Filho - 2014.pdf: 933703 bytes, checksum: d3e9380eac662d534b9a901b441bbab0 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2015-02-05T14:22:22Z (GMT) No. of bitstreams: 2 Dissertação - Jaires Gomes de Oliveira Filho - 2014.pdf: 933703 bytes, checksum: d3e9380eac662d534b9a901b441bbab0 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2015-02-05T14:22:22Z (GMT). No. of bitstreams: 2 Dissertação - Jaires Gomes de Oliveira Filho - 2014.pdf: 933703 bytes, checksum: d3e9380eac662d534b9a901b441bbab0 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2014-02-14 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Ticks are arthropods of great importance in public health, due to the transmission of many pathogens. Rhipicephalus sanguineus parasites mainly dogs. It is known that Beagle dogs are less susceptible to R. sanguineus than English Cocker Spaniel, and still have resistance patterns linked to immunity. The lower susceptibility of Beagle dogs is due to chemical compounds they produce, which act in reducing the parasitic load of R. sanguineus on these animals. Given that this research aimed to verify the chemical repellency against R. sanguineus of compounds that have been identified in the odor of resistant dogs, and synthetic repellent compounds to other tick species. For testing chemical repellency two tests were used, the Petri dish and the Y-olfactometer. Five compounds identified in Beagle odors were selected and tested: 2 - hexanone, nonane, decane, undecane and benzaldehyde, the compound of botanical origin β-citronellol and the standard repellent DEET (N,N-diethyl-3-methylbenzamide). These compounds were tested alone and also two mixtures were evaluated: benzaldehyde and 2-hexanone (1:1), and benzaldehyde, 2-hexanone and undecane (1:1:1). All these compounds were prepared in a stock solution of 7.2 % ( ≈ 0.200 mg/cm²) and two lower concentrations were also tested: 0.100 and 0.050 mg/cm². DEET was repellent in the two highest concentrations and 68.33 to 86.67% of the ticks were found in untreated areas in different time points. At the concentration of 0.050 mg/cm² ticks were distributed similarly (without significant difference) in both areas. β-citronellol was the only compound tested that was repellent at all times and concentrations tested. The percentage of ticks in untreated areas ranged from 73.33 to 93.33 %. When compared β-citronellol with DEET the first compound was more effective at repelling the adults of R. sanguineus. For benzaldehyde, 30 minutes at a concentration of 0.200 mg/cm² a percentage of 63.33 % of ticks was observed in the untreated area. Percentage of 76.67 was observed after 5 min. at a concentration of 0.050 mg/cm². 2-hexanone was repellent at 30 min. at a concentration of 0.200 mg/cm² at 10 min. at a concentration of 0.100 mg/cm² and 30 minutes at a concentration of 0.050 mg/cm². For undecane a rate of 65.00% of ticks was observed in the untreated area in one moment of testing, the highest concentration during the first 5 min. of the evaluation. Nonane and decane not were not repellent at any of the concentrations and time intervals. The blend benzaldehyde + 2-hexanone was repellent in the three highest concentrations in almost all evaluated times, including in the olfactometer testing. During the whole test this mixture showed statistical similarity when compared with DEET. The addition of undecane to this blend did not potentiate its repellent power. The main result was the finding of natural repellents in resistant dogs to the tick R. sanguineus. / Carrapatos são artrópodes de grande importância dentro da saúde pública, devido à transmissão de inúmeros patógenos. Rhipicephalus sanguineus parasita principalmente cães. Sabe-se que cães da raça Beagle são menos susceptíveis ao R. sanguineus que cães Cocker Inglês, e ainda apresentam padrões de resistência ligados a imunidade. A menor susceptibilidade de cães Beagle está ligada a compostos químicos que estes produzem, os quais atuam na diminuição da carga parasitária de R. sanguineus sobre estes animais. Sabendo-se disso com esta pesquisa objetivou-se verificar a repelência química de compostos que foram identificados no odor de cães resistentes, além de compostos sintéticos repelentes para outros carrapatos, contra o R. sanguineus. Para os testes de repelência química foram utilizados dois ensaios de repelência, o da placa de Petri e do olfatômetro em Y. Foram testados cinco compostos com provável poder repelente e identificados nos odores de Beagle (2-hexanona, nonano, decano, undecano e benzaldeído), o composto de origem botânica β-citronelol e o repelente padrão DEET (N,N-dietil-3-metilbenzamida). Além destes compostos testados isoladamente, duas misturas foram avaliadas: benzaldeído e 2 -hexanona (1:1), e benzaldeído, 2-hexanona e undecano (1:1:1) Todos estes compostos foram formulados a partir de uma solução mãe de 7,2% (≈ 0,200 mg/cm²) da qual foi obtida posteriormente outras duas concentrações (0,100 e 0,050 mg/cm²). O DEET foi repelente nas duas maiores concentrações, sendo que 68,33 a 86,67% dos carrapatos foram encontrados nas áreas não tratadas, nos diferentes tempos de observação. Na concentração de 0,050 mg/cm² os carrapatos se distribuíram similarmente (sem diferença significativa) em ambas as áreas. β-citronelol foi o único composto testado que foi repelente em todos os tempos e concentrações testados. Os percentuais de carrapatos nas áreas não tratadas variaram de 73,33 a 93,33%. Quando comparado com o DEET o β-citronelol foi mais eficiente em repelir os adultos de R. sanguineus. Para o benzaldeido, aos 30 minutos, na concentração de 0,200 mg/cm² foi observado um percentual de 63,33% de carrapatos na área não tratada. Percentual de 76,67 foi observado aos cinco minutos, na concentração de 0,050 mg/cm². A 2-hexanona foi repelente aos 30 minutos, na concentração de 0,200 mg/cm², aos 10 minutos, na concentração de 0,100 mg/cm² e aos 30 minutos, na concentração de 0,050 mg/cm². Para o undecano foi observado um percentual de 65,00 de carrapatos na área não tratada em apenas um momento dos testes, na maior concentração, durante os primeiros cinco minutos de avaliação. Nonano e decano não causaram qualquer repelência para os carrapatos testados, em qualquer uma das concentrações ou intervalos de tempo avaliados. A mistura benzaldeido + 2-hexanona foi repelente nas três maiores concentrações, em quase todos os tempos avaliados, inclusive no teste de olfatometria. Durante todo o teste esta mistura mostrou semelhança estatística quando comparada com o DEET. A adição de undecano a esta mistura não potencializou o seu poder repelente. O principal resultado obtido foi a constatação da presença de repelentes naturais em cães resistentes ao carrapato R. sanguineus.

<p>In electrochemical oxidation treatment of wastewater, the electrode material is an important parameter in optimizing oxidative electrochemical processes, since the mechanism and products of several anodic reactions are known to depend on the anode material. The electrochemical oxidation of benzaldehyde, nitrobenzene and m-cresol on bare boron-doped diamond (BDD) electrode was investigated. Cytochrome c was then electrochemically immobilsed onto the functionalized BDD electrode by cyclic voltammetry. Oxidation and reduction reaction mechanism of each flavonoid was studied. There was one oxidation and reduction peaks for quercitin and catechin respectively, and two oxidation and two reduction peaks for rutin. The cytochrome c modified BDD electrode showed good sensitivity for all three flavonoids and low detection limits i.e. 0.42 to 11.24 M as evaluated at oxidation and reduction peaks, respectively.</p>

The large pine weevil, Hylobius abietis L., is a major insect pest on conifer seedlings in northern Europe. Due to its feeding newly planted trees get girdled, resulting in high seedling mortality (up to 80%). As a consequence great financial losses to the forest industry occur. Today the seedlings are protected with the pyrethroid insecticide cypermethrin. This insecticide is toxic to aquatic organisms and is, from 2010, prohibited for use in Sweden by the Swedish Chemicals Inspectorate. An alternative to insecticides is to protect the seedlings with antifeedants, compounds that, either through taste or smell or both, deter the weevils from feeding. This thesis describes the search for and the synthesis of such antifeedant compounds. Bark extracts of several woody species, known to be non-palatable to the weevil, were prepared and found to display antifeedant activity against H. abietis. The major chemical constituents of the extracts were tested for antifeedant activity. Antifeedants such as eugenol, 2-phenylethanol and benzylalcohol, but also feeding stimulants such as β-sitosterol and linoleic acid, were identified. An extract of linden bark, Tilia cordata, was shown to contain nonanoic acid, a highly active antifeedant. Other aliphatic carboxylic acids were also found to display high antifeedant activities against the weevil, both in laboratory and in field tests. The enantiomers of dihydropinidine, a piperidine alkaloid present in several conifer species, were prepared by dimethylzinc mediated allylation of 2- methyltetrahydropyridine-N-oxide. When tested in micro feeding assays, no difference in antifeedant activity was found for the enantiomers. In a field test high antifeedant activity, comparable with that of the presently used insecticide cypermethrin, was found for (±)-dihydropindine. Other naturally occurring piperidine alkaloids were synthesised and also found to display high antifeedant activities in laboratory tests. Structure-activity relationships were evaluated for methoxy substituted benzaldehydes, benzoic acids and cinnamic aldehydes, -acids, -esters and -alcohols. While the carboxylic acids were inactive or even feeding stimulants, the aldehydes were the most active antifeedants / QC 20110124

<p>The large pine weevil, Hylobius abietis L., is a major insect pest on conifer seedlings in northern Europe. Due to its feeding newly planted trees get girdled, resulting in high seedling mortality (up to 80%). As a consequence great financial losses to the forest industry occur. Today the seedlings are protected with the pyrethroid insecticide cypermethrin. This insecticide is toxic to aquatic organisms and is, from 2010, prohibited for use in Sweden by the Swedish Chemicals Inspectorate. An alternative to insecticides is to protect the seedlings with antifeedants, compounds that, either through taste or smell or both, deter the weevils from feeding. This thesis describes the search for and the synthesis of such antifeedant compounds.</p><p>Bark extracts of several woody species, known to be non-palatable to the weevil, were prepared and found to display antifeedant activity against H. abietis. The major chemical constituents of the extracts were tested for antifeedant activity. Antifeedants such as eugenol, 2-phenylethanol and benzylalcohol, but also feeding stimulants such as β-sitosterol and linoleic acid, were identified. An extract of linden bark, Tilia cordata, was shown to contain nonanoic acid, a highly active antifeedant. Other aliphatic carboxylic acids were also found to display high antifeedant activities against the weevil, both in laboratory and in field tests.</p><p>The enantiomers of dihydropinidine, a piperidine alkaloid present in several conifer species, were prepared by dimethylzinc mediated allylation of 2- methyltetrahydropyridine-N-oxide. When tested in micro feeding assays, no difference in antifeedant activity was found for the enantiomers. In a field test high antifeedant activity, comparable with that of the presently used insecticide cypermethrin, was found for (±)-dihydropindine. Other naturally occurring piperidine alkaloids were synthesised and also found to display high antifeedant activities in laboratory tests.</p><p>Structure-activity relationships were evaluated for methoxy substituted benzaldehydes, benzoic acids and cinnamic aldehydes, -acids, -esters and -alcohols. While the carboxylic acids were inactive or even feeding stimulants, the aldehydes were the most active antifeedants</p>

<p>In electrochemical oxidation treatment of wastewater, the electrode material is an important parameter in optimizing oxidative electrochemical processes, since the mechanism and products of several anodic reactions are known to depend on the anode material. The electrochemical oxidation of benzaldehyde, nitrobenzene and m-cresol on bare boron-doped diamond (BDD) electrode was investigated. Cytochrome c was then electrochemically immobilsed onto the functionalized BDD electrode by cyclic voltammetry. Oxidation and reduction reaction mechanism of each flavonoid was studied. There was one oxidation and reduction peaks for quercitin and catechin respectively, and two oxidation and two reduction peaks for rutin. The cytochrome c modified BDD electrode showed good sensitivity for all three flavonoids and low detection limits i.e. 0.42 to 11.24 M as evaluated at oxidation and reduction peaks, respectively.</p>

19 Dec 2004. / Published through the Information Bridge: DOE Scientific and Technical Information. "IS-T 2117" Guodong Du. 12/19/2004. Report is also available in paper and microfiche from NTIS.

Magister Scientiae - MSc / In electrochemical oxidation treatment of wastewater, the electrode material is an important parameter in optimizing oxidative electrochemical processes, since the mechanism and products of several anodic reactions are known to depend on the anode material. The electrochemical oxidation of benzaldehyde, nitrobenzene and m-cresol on bare boron-doped diamond (BDD) electrode was investigated. Cytochrome c was then electrochemically immobilsed onto the functionalized BDD electrode by cyclic voltammetry. Oxidation and reduction reaction mechanism of each flavonoid was studied. There was one oxidation and reduction peaks for quercitin and catechin respectively, and two oxidation and two reduction peaks for rutin. The cytochrome c modified BDD electrode showed good sensitivity for all three flavonoids and low detection limits i.e. 0.42 to 11.24 M as evaluated at oxidation and reduction peaks, respectively. / South Africa