Creating a Thermostable β-Glucuronidase Switch for Homogeneous Immunoassay by Disruption of Conserved Salt Bridges at Diagonal Interfaces

Production of bilirubin via whole-cell transformation utilizing recombinant Corynebacterium glutamicum expressing a β-glucuronidase from Staphylococcus sp. RLH1

Bilirubin, a key active ingredient of bezoars with extensive clinical applications in China, is produced through a chemical process. However, this method suffers from inefficiency and adverse environmental impacts. To address this challenge, we present a novel and efficient approach for bilirubin production via whole-cell transformation. In this study, we employed Corynebacterium glutamicum ATCC13032 to express a β-glucuronidase (StGUS), an enzyme from Staphylococcus sp. RLH1 that effectively hydrolyzes conjugated bilirubin to bilirubin. Following the optimization of the biotransformation conditions, a remarkable conversion rate of 79.7% in the generation of bilirubin was obtained at temperate 40 °C, pH 7.0, 1 mM Mg2+ and 6 mM antioxidant NaHSO3 after 12 h. These findings hold significant potential for establishing an industrially viable platform for large-scale bilirubin production.