The Use of Salt Hydrates as Water buffers To Control Enzyme Activity in Organic Solvents

Robb, Donald A.; Yang, Zhen; Halling, Peter J.

doi:10.3109/10242429408992127

Cited by 17 publications

(5 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In our work, the bulk solvent phase (containing the substrate[s]) was pre-equilibrated with salt hydrates, but this might not be sucient to retain a constant a w value during reaction (which releases water) if the hydration/ dehydration equilibrium of the salt hydrate did not respond rapidly. On these grounds, we also excluded zinc sulphate heptahydrate (a w = 0.63 at 25°C) and sodium tartrate dihydrate (a w = 0.86 at 25°C) because it has been shown that they release their water of crystallisation at such a slow rate that they are of little use (Robb et al, 1994). We con®rmed that those salt hydrates selected demonstrated no lag phase in enzyme activity.…”

Section: Discussionmentioning

confidence: 99%

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

Alston¹,

Freedman²

2002

Biotech & Bioengineering

View full text Add to dashboard Cite

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.

show abstract

Section: Discussionmentioning

confidence: 99%

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

Alston¹,

Freedman²

2002

Biotech & Bioengineering

View full text Add to dashboard Cite

show abstract

“…In reactions where water is not produced, the initial water activity of the reaction medium is fixed and the change in water activity, which is caused by changes in the polarity of the reaction medium, is neglected. In the case of esterifications, where the water activity of the reaction medium significantly increases as the reaction proceeds, the water activity must be constantly controlled [16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

The Role of Water Activity in Terms of Enzyme Activity and Enantioselectivity during Enzymatic Esterification in Non-conventional Media

Lajtai-Szabó¹,

Nemestóthy²,

Gubicza³

2020

Hung. J. Ind. Chem.

View full text Add to dashboard Cite

“…Water activity (a w ) is an important parameter in biocatalysis [8,9,42,43], since the hydration of the enzyme surface depends on the water activity in the solvent (solvent plus water) medium. Constraints are imposed in order to preserve this hydration level.…”

Section: Essential Watermentioning

confidence: 99%

Computer-aided solvent screening for biocatalysis

Abildskov¹,

Leeuwen²,

Boeriu³

et al. 2013

Journal of Molecular Catalysis B: Enzymatic

View full text Add to dashboard Cite

A computer-aided solvent screening methodology is described and tested for biocatalytic systems composed of enzyme, essential water and substrates/products dissolved in a solvent medium, without cells. The methodology is computationally simple, using group contribution methods for calculating constrained properties related to chemical reaction equilibrium, substrate and product solubility, water solubility, boiling points, toxicity and others. Two examples are provided, covering the screening of solvents for lipase-catalyzed transesterification of octanol and inulin with vinyl laurate. Esterification of acrylic acid with octanol is also addressed. Solvents are screened and candidates identified, confirming existing experimental results. Although the examples involve lipases, the method is quite general, so there seems to be no preclusion against application to other biocatalysts.

show abstract

The Use of Salt Hydrates as Water buffers To Control Enzyme Activity in Organic Solvents

Cited by 17 publications

References 9 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

The Role of Water Activity in Terms of Enzyme Activity and Enantioselectivity during Enzymatic Esterification in Non-conventional Media

Computer-aided solvent screening for biocatalysis

Contact Info

Product

Resources

About