The Role of Water in Gaseous Biocatalysis

Robert, Hervé; Lamare, Sylvain; Parvaresh, Firooze; Legoy, Marie‐Dominique

doi:10.1016/b978-0-444-89046-7.50019-9

Cited by 15 publications

(15 citation statements)

References 18 publications

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“…Thè`p lateau'' corresponds to the ®rst hydration layer of water around the protein, and the subsequent increase in adsorbed water corresponds to the presence of``free'' water around the protein (secondary or tertiary hydration layers?) (Robert et al, 1992). Therefore, catalysis of the transesteri®cation reaction with the 3°and 2°alco-hols (3-methyl-3-hexanol and 2-heptanol, respectively) is optimal in the presence of a single hydration layer around the enzyme and reduced on the appearance of`f ree'' water.…”

Section: Discussionmentioning

confidence: 97%

A comparison of lipase‐catalysed ester and lactone synthesis in low‐water systems: Analysis of optimum water activity

Alston¹,

Freedman²

2002

Biotech & Bioengineering

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We investigated the effects of the lyophilisation medium (enzyme plus buffer salt and additives) and of water activity (a(w)) on the catalytic properties of lipase from Chromobacterium viscosum (lipase CV) in organic solvents; catalysis of ester and lactone synthesis were compared and, despite the similarities of the reactive groups involved in these reactions, some interesting differences were observed. Including 2-[N-morpholino]ethanesulfonic acid (MES) buffer in the lyophilisation medium of lipase CV increased its catalytic activity in transesterification and lactonisation, although the buffer salt requirement for maximal activity differed between the two reactions. Sorbitol, glucose, lactose, 18-crown-6 (crown ether 18-C-6), beta-cyclodextrin and bovine serum albumin were employed as alternative additives in the transesterification reaction, but were not as effective as MES buffer. Salt hydrates were used to investigate the effect of a(w) on esterification and lactonisation reactions catalysed by lipase CV. The maximum rate of hexadecanolide synthesis in toluene occurred at a(w) = 0.48. The optimum a(w) for the transesterification reaction in heptane/alcohol mixtures depended on the alcohol substrate employed (1-heptanol, 2-heptanol, or 3-methyl-3-hexanol) but not on the acyl donor (p-NP acetate or caprylate). The optimum a(w) values for both reactions were unchanged when a common solvent system (toluene/1-heptanol) was employed, indicating that the dependence of enzyme activity on a(w) is an intrinsic property of the enzyme-catalysed reaction and not a function of the solvent or other additives.

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Section: Discussionmentioning

confidence: 97%

A comparison of lipase‐catalysed ester and lactone synthesis in low‐water systems: Analysis of optimum water activity

Alston¹,

Freedman²

2002

Biotech & Bioengineering

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“…In the case of gas/solid catalysis with lipases, several days of continuous reactor operation at temperatures up to 100°C were achieved (16). Until today, however, only a few examples were known, in which alcohol dehydrogenases were used to catalyze gas-phase reactions (1,8,(22)(23)(24)(25). Besides being labile enzymes, alcohol dehydrogenases require a nicotinamide cofactor NAD(P), which is expensive and sensitive to temperature (26).…”

Section: Introductionmentioning

confidence: 98%

“…Up to now, enzymatic gasphase reactions were mostly conducted with stable enzymes, such as alcohol oxidases (3-7), cutinases (2,(8)(9)(10)(11), and lipases (2,8,(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22). In the case of gas/solid catalysis with lipases, several days of continuous reactor operation at temperatures up to 100°C were achieved (16).…”

Section: Introductionmentioning

confidence: 99%

Optimization of Enzymatic Gas-Phase Reactions by Increasing the Long-Term Stability of the Catalyst

et al. 2004

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Enzymatic gas-phase reactions are usually performed in continuous reactors, and thus very stable and active catalysts are required to perform such transformations on cost-effective levels. The present work is concerned with the reduction of gaseous acetophenone to enantiomerically pure (R)-1-phenylethanol catalyzed by solid alcohol dehydrogenase from Lactobacillus brevis (LBADH), immobilized onto glass beads. Initially, the catalyst preparation displayed a half-life of 1 day under reaction conditions at 40 degrees C and at a water activity of 0.5. It was shown that the observed decrease in activity is due to a degradation of the enzyme itself (LBADH) and not of the co-immobilized cofactor NADP. By the addition of sucrose to the cell extract before immobilization of the enzyme, the half-life of the catalyst preparation (at 40 degrees C) was increased 40 times. The stabilized catalyst preparation was employed in a continuous gas-phase reactor at different temperatures (25-60 degrees C). At 50 degrees C, a space-time yield of 107 g/L/d was achieved within the first 80 h of continuous reaction.

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“…The first experiments were performed with isolated enzymes and static devices (Kimamura et al, 1979;Yagi et al, 1969). Solid/gas technology has then been developed Legoy, 1993, 1995a,b;Robert et al, 1992) and has proved to be an interesting tool both for fundamental research on the intrinsic properties of enzymes and for technological applications . On the fundamental point of view, this technology has allowed to gain information on the role of water, or organic species on biocatalysis (Graber et al, , 2008; Leonard et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Dehalogenation of gaseous 1‐chlorobutane by dehydrated whole cells: Influence of the microenvironment of the halidohydrolase on the stability of the biocatalyst

Marchand

Lamare²,

Legoy³

et al. 2009

Biotech & Bioengineering

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It was observed that a biocatalyst prepared from dehydrated whole cells of a recombinant Escherichia coli (initially suspended in borate buffer) was able to hydrolyze gaseous 1-chlorobutane in a solid/gas reactor. Nevertheless, at 40 degrees C and for a 0.7 water activity, it rapidly lost its activity. The explanation of this phenomenon was first investigated by observing the biocatalyst structure at the microscopic level and by studying the localization of the dehalogenase involved in catalysis (intracellular/extracellular). The behavior of this biocatalyst was then compared with that of a preparation made from cells extracts. The reasons of the inactivation are discussed in terms of thermal denaturation and protective effect of buffer salts.

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The Role of Water in Gaseous Biocatalysis

Cited by 15 publications

References 18 publications

A comparison of lipase‐catalysed ester and lactone synthesis in low‐water systems: Analysis of optimum water activity

A comparison of lipase‐catalysed ester and lactone synthesis in low‐water systems: Analysis of optimum water activity

Optimization of Enzymatic Gas-Phase Reactions by Increasing the Long-Term Stability of the Catalyst

Dehalogenation of gaseous 1‐chlorobutane by dehydrated whole cells: Influence of the microenvironment of the halidohydrolase on the stability of the biocatalyst

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