INTRODUCTION

Cellobiose 2-epimerase (CE) catalyzes the interconversion of glucosyl and mannosyl groups at the reducing end of β-1,4-linked disaccharides. This enzyme is pivotal for converting lactose into prebiotics like epilactose, offering a potential solution for lactose-intolerant-friendly dairy products. However, current CEs are hindered by pH and thermal instability in milk processing, as their neutral-to-alkaline pH optima clash with milk’s mildly acidic conditions (pH 6.5–6.7), and their poor thermolability requires costly post-processing enzyme removal.