ESR 4: Niamh Ainsworth

 

Niamh is working on the area of enzyme stability, with a particular emphasis on laundry applications. Enzymes such as proteases, amylases and lipase are crucial components of modern detergents that enable the global adoption of lower temperature washes with huge benefits in terms of energy reduction.

One of the key issues, particularly with liquid or “unit dose” formulations and in warm-climate markets, is enzyme stability. Niamh has been investigating a range of methods for measuring stability in product formulations where many conventional assays are rendered impractical. Particularly promising methods include nano-differential-scanning calorimetry and a new pulsed proteolysis method, both of which probe Tm, the characteristic temperature for protein unfolding. Pulse proteolysis works by using a protease, thermolysin, that is selective for the hydrophobic portions of the enzyme that are protected in the folded state. Unfolded enzymes are broken down such that detection of a mass component corresponding to the intact enzyme (for example by gel or HPLC methods) signals enzyme stability. Quantification of the temperature dependence of the relative amounts of folded and unfolded protein allows access to a Tm value, which can be achieved in detergent formulation environments of different complexities.

The results she obtains will be bench-marked against conventional storage-based methods at P&G Brussels, which use activity-based spectrophotometric assays as measures of enzyme stability. Niamh’s new methods applied in detergent media will particularly target earlier detection of protein denaturation when activity assays still show close to maximal enzyme performance. Niamh will therefore be able to develop new screening technologies for the faster evaluation of the short and longer term stabilities of new biological cleaning technologies globally. She is preparing a tutorial review article on her toolbox of techniques for Chem. Soc. Rev. to disseminate the methods she has developed.

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Contact Details: N.M.Ainsworth@durham.ac.uk

Supervisors:

authors: J. Evans and N. Ainsworth