D-Allulose is a high-value, low-calorie rare sugar with significant potential in the food and pharmaceutical industries. Its industrial synthesis relies on D-allulose 3-epimerase (DAE) for the C3-epimerization of D-fructose. While the benchmark Agrobacterium tumefaciens DAE (AtDAE) achieves a conversion yield of up to 33 %, its dependence on toxic cobalt (Co²⁺) or manganese (Mn²⁺) ions limits its adoption in food-grade manufacturing. In this study, a putative DAE from Ruania alba (RaDAE), sharing only 31% sequence identity with AtDAE, was investigated as a potential food-safe biocatalyst. Sequence analysis revealed a unique metal-binding region, supporting a distinct preference for magnesium (Mg²⁺), a safer, food-compatible cofactor. Notably, RaDAE exhibited optimal activity at 65 °C, demonstrating significantly higher thermal tolerance than AtDAE. Under initial test conditions at pH 7.5 and 65 °C, RaDAE achieved a D-fructose to D-allulose conversion yield of approximately 32%. Despite the low sequence identity, this competitive performance and superior thermostability identify RaDAE as a promising candidate for further optimization and sustainable, large-scale synthesis of rare sugars.