Fructose-aided cross-linked enzyme aggregates of laccase: An insight on its chemical and physical properties

Abstract

Regardless of the wide biotechnological application of laccases, the critical limiting factors, namely: reusability, retrieval, and storage stability still prevail. These essential traits are rehabilitated by crosslinking laccases, albeit at the expense of their enzymatic activity. To overcome such constraints, we prepared crosslinked enzyme aggregates (CLEAs) of laccase from Trametes versicolor with the aid of sugars. The parameters such as, type of precipitant, crosslinking time, crosslinker and sugar concentration were optimised. The sugar CLEAs were compared with the classic BSA and GA laccase CLEAs concerning physico-chemical properties. The activity recovery for fructose-CLEA was ∼45%. Moreover, the Kcat/Km values of the CLEAs were two and three-fold higher than BSA-CLEA and GA-CLEA, respectively. The half-life (t1/2) deciphered by sugar-CLEA was higher than the t1/2 of GA-CLEAs and free enzyme at 50 °C, portraying more thermal stability. Besides, it demonstrated high pH stability, which was analogous to BSA-CLEA. The promising attributes of increased storage stability and recyclability (>80%) gives more edge to the sugar-CLEAs over conventional CLEAs of their corresponding free enzyme. Thus, sugar-CLEA prevails in furnishing the rudimentary properties required for a biocatalyst and holds many prospects.