Immobilized enzymes: crystals or carriers?

Tischer, Wilhelm; Kasche, Volker

doi:10.1016/s0167-7799(99)01322-0

Cited by 378 publications

(206 citation statements)

References 30 publications

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“…Thus process conditions (e.g., the type and use of immobilized enzymes) have considerable influence over the maximum achievable turnover exhibited by the biocatalyst. Such chemical modifications frequently result in lowering of k cat values, attributed to a range of effects, including variations in protein flexibility and allosteric properties (conformational), decreased accessibility to the enzyme active site 20 (steric), and changes in the enzyme microenvironment by the selective attraction or exclusion of water, ions, solutes, and so on 21 .…”

Section: Product Recoverymentioning

confidence: 99%

The search for the ideal biocatalyst

2002

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While the use of enzymes as biocatalysts to assist in the industrial manufacture of fine chemicals and pharmaceuticals has enormous potential, application is frequently limited by evolution-led catalyst traits. The advent of designer biocatalysts, produced by informed selection and mutation through recombinant DNA technology, enables production of process-compatible enzymes. However, to fully realize the potential of designer enzymes in industrial applications, it will be necessary to tailor catalyst properties so that they are optimal not only for a given reaction but also in the context of the industrial process in which the enzyme is applied.The past two decades have led to major advances in our understanding of the subtleties of protein structure-function interrelationships. Mechanisms of protein stability in aqueous and nonaqueous environments 1,2 , the links between conformational mobility, structural integrity and activity 3,4 , and the complexities of substrate specificity have all succumbed to the onslaught of advanced molecular methods, including crystallography 5-7 , site-specific mutagenesis, gene shuffling, and protein evolution [8][9][10][11] . Scientists are now in a position to visualize, if not design, catalytic systems that approach the functional "ideal".The "ideal" catalyst is typically considered by the biochemist in terms of turnover number (k cat ) or, for a given process, in terms of maximum specificity constant (A cat /KM). However, from a bioprocess viewpoint, each bioprocess is constrained by a set of conditions dictated by the specific properties of the substrates, products, and the bioconversion reaction. Thus, while for any given bioprocess it is clearly possible to specify a set of catalyst properties that would constitute the ideal for that process, only broad generalizations for ideality may otherwise be identified.In this review, we discuss molecular properties of enzymes from a bioprocess viewpoint. A paradigm for design based on the ideal process determining the desired features of the catalyst is presented. "Ideal" characteristics (generic and process-specific) and methodologies for seeking or engineering these are discussed. We then review the extent to which significant changes in protein functional properties have been achieved by application of these methods, together with issues that require more research and/or development. Ideal processesBioprocess engineers develop processes not only against fixed capital and operating expenditure, but also rapid, and often, very aggressive timelines. This is particularly the case for pharmaceutical products where patent expiry on the product demands a robust and scalable process with short development times 12 . Conventionally, once a synthetic route is fixed and the biocatalytic step defined, bioprocess design and operation are centered on the properties of the

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Section: Product Recoverymentioning

confidence: 99%

The search for the ideal biocatalyst

2002

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“…Immobilized enzymes present several benefits over the free one such as enhanced stability, ease of separation from the reaction mixture, significant savings in enzyme consumption, and usually improved activity [6]. The immobilization methods include physical adsorption, covalent attachment and entrapment in inorganic and organic matrices [3].…”

Section: Introductionmentioning

confidence: 99%

Covalent immobilization of porcine pancreatic lipase on carboxyl-activated magnetic nanoparticles: Characterization and application for enzymatic inhibition assays

Zhu

Ren

Liu

et al. 2014

Materials Science and Engineering: C

140

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“…A tecnologia de imobilização de enzimas envolve basicamente a escolha de um suporte e do método de imobilização nesse suporte, que resulte num preparado imobilizado ativo e estável 7 . Dispõe-se atualmente de várias técnicas de imobilização de enzimas, assim como de um grande número de matrizes, englobando materiais orgânicos e inorgânicos, naturais ou sintéticos 6,7 .…”

Section: Introductionunclassified

“…Dispõe-se atualmente de várias técnicas de imobilização de enzimas, assim como de um grande número de matrizes, englobando materiais orgânicos e inorgânicos, naturais ou sintéticos 6,7 .…”

Section: Introductionunclassified

Comparação do desempenho da lipase de candida rugosa imobilizada em suporte híbrido de polissiloxano-polivinilálcool empregando diferentes metodologias

Paula¹,

Moreira²,

Braga³

et al. 2008

Quím. Nova

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a. Sara Mesquita, 2270, 60511-110 Fortaleza -CE, Brasil Recebido em 16/10/06; aceito em 25/5/07; publicado na web em 9/11/07 COMPARATIVE PERFORMANCE OF Candida rugosa LIPASE IMMOBILIZED ON POLYSILOXANE POLYVINYL ALCOHOL HYBRID SUPPORT USING DIFFERENT METHODOLOGIES. The efficiency for immobilizing microbial Candida rugosa lipase on a hybrid matrix of polysiloxane polyvinyl alcohol, by adsorption, covalent coupling and encapsulation was compared. The activities of immobilized derivatives were evaluated using p-nitrophenylpalmitate (hydrolysis) and butyric acid and butanol (esterification) as substrates. Operational stability and storage tests were also performed. Among the procedures tested, the proposed matrix was efficient for immobilizing C. rugosa lipase by adsorption and covalent coupling techniques and unsuitable for encapsulation purposes. The results reveal that better catalytic properties in both aqueous and organic media were demonstrated by the covalent coupling POS-PVA immobilized lipase, including also satisfactory half-life and good storage stability.Keywords: lipase; hybrid support; adsorption. INTRODUÇÃOEnzimas na sua forma nativa (enzimas livres) têm sido usadas por séculos na indústria de alimentos e mais recentemente nas indústrias farmacêuticas e químicas 1 . Sua estrutura e modo de ação vêm sendo gradativamente elucidados por métodos experimentais bem estabelecidos, como técnicas clássicas de Raio-X e avançadas de Ressonância Nuclear Magnética (RNM). Modernas metodologias de engenharia genética têm possibilitado a produção de enzimas em larga escala ou a modificação de sua estrutura primária, alterando, portanto, algumas de suas características físico-químicas e biológicas 2 . De igual significância são as recentes técnicas de evolução direcionada, as quais têm permitido, via modificação do DNA, a preparação de enzimas especialmente dirigidas para uma determinada finalidade, isto é, enzimas que atuam em valores extremos de pH e temperatura, bem como em presença de meios não convencionais (solventes orgânicos, fase gasosa e CO 2 supercrítico) 3 .O valor de venda de enzimas para uso em indústrias de alimentos, detergentes, especialidades químicas perfizeram um total de aproximadamente US$ 700 milhões em 1992 e aumentaram para US$ 2 bilhões em 2004 4 . De acordo com as projeções, o crescimento no mercado de enzimas é de aproximadamente 4-5% ao ano, acompanhada pela redução de preço, devido ao grande núme-ro de empresas que vêm comercializando enzimas com preços mais competitivos. Como resultado, o mercado previsto para 2009 é da ordem de 2,4 bilhões 4 .De interesse particular é o aumento do uso de enzimas imobilizadas, termo empregado por Katchalski-Katzir 5 na primeira Conferência de Engenharia Enzimática realizada em Henniker, NH, EUA em 1971, para designar enzima fisicamente confinada ou localizada numa certa região do espaço, com retenção de sua atividade catalítica, podendo ser usada repetida e continuamente 6 . Nesta técnica, a enzima fica retida no interior (poros) ou na superfície de u...

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Immobilized enzymes: crystals or carriers?

Cited by 378 publications

References 30 publications

The search for the ideal biocatalyst

The search for the ideal biocatalyst

Covalent immobilization of porcine pancreatic lipase on carboxyl-activated magnetic nanoparticles: Characterization and application for enzymatic inhibition assays

Comparação do desempenho da lipase de candida rugosa imobilizada em suporte híbrido de polissiloxano-polivinilálcool empregando diferentes metodologias

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