Investigation into immobilisation of lactate oxidase to improve stability

Lactate oxidase (LOx) is an unstable enzyme. In this work, a variety of immobilisation techniques are investigated in an effort to improve the long-term stability of the enzyme. These include covalent linkage to two membrane types, encapsulation in a BSA gel and four different sol-gel matrices. The enzyme glucose oxidase (GOx) was also immobilised in the same sol-gel matrices. The methods were assessed for both activity and stability of the enzyme and the mechanical rigidity of the matrix. The BSA and sol-gels both formed physically robust enzyme layers. The enzyme retained its activity in the BSA gel for 20 days. Activity of the enzyme was much higher in the sol-gel matrices and remained stable fur at least 55 days. Sol-gel processing conditions were also investigated. (C) 2000 Elsevier Science S.A. All lights reserved.