Highly selective whole-cell 25-hydroxyvitamin D synthesis using molybdenum-dependent C25-steroid dehydrogenase and cyclodextrin recycling.

Background: The global prevalence of vitamin D (VitD) deficiency associated with numerous acute and chronic diseases has led to strategies to improve the VitD status through dietary intake of VitD-fortified foods and VitD supplementation. In this context, the circulating form of VitD (cholecalciferol) in the human body, 25-hydroxy-VitD (calcifediol, 25OHVitD), has a much higher efficacy in improving the VitD status, which has motivated researchers to develop methods for its effective and sustainable synthesis. Conventional monooxygenase-/peroxygenase-based biocatalytic platforms for the conversion of VitD to value-added 25OHVitD are generally limited by a low selectivity and yield, costly reliance on cyclodextrins and electron donor systems, or by the use of toxic co-substrates.