Heat treatment

In many cases, unwanted enzyme activities may be removed by heat treatment. Different enzymes have differing susceptibility to heat denaturation and precipitation. Where the enzyme required is relatively heat-stable this allows its easy and rapid purification in terms of enzymic activity. For such enzymes heat-treatment is always considered as an option at an early stage in their purification. This method has been particularly successfully applied to the production of glucose isomerase, where a short incubation at a relatively high temperature is used (e.g., 60 - 85°C for 10 min). No interfering activity remains after this treatment and the heat-treated, and hence leaky, cells may be immobilised and used directly.