Highly selective whole-cell 25-hydroxyvitamin D₃ synthesis using molybdenum-dependent C25-steroid dehydrogenase and...

Area of Science:

• Biotechnology
• Biocatalysis
• Metabolic Engineering

Background:

• Vitamin D deficiency is a global health concern, necessitating strategies for improving vitamin D status.
• 25-hydroxy-vitamin D3 (25OHVitD3) is the active circulating form of vitamin D3 with higher efficacy.
• Conventional methods for 25OHVitD3 synthesis face limitations in selectivity, yield, and cost.

Purpose of the Study:

• To develop an efficient and sustainable whole-cell biocatalytic system for 25OHVitD3 synthesis.
• To overcome the limitations of existing methods for vitamin D3 hydroxylation.

Main Methods:

• Engineered Thauera aromatica to produce a molybdenum-dependent steroid C25 dehydrogenase.
• Utilized a whole-cell approach under semi-aerobic conditions for vitamin D3 conversion.
• Employed O2 or ferricyanide as electron acceptors, independent of external electron donor systems.

Main Results:

• Achieved a maximum 25OHVitD3 titer of 1.85 g L-1 within 50 hours with a 99% yield.
• Demonstrated 2.2-fold higher yield compared to previous biocatalytic systems.
• Developed a cyclodextrin recycling method, enabling reuse for 10 cycles without significant loss.

Conclusions:

• The steroid C25 dehydrogenase-based whole-cell system offers superior selectivity and yield for 25OHVitD3 production.
• This system is independent of electron donors and avoids toxic co-substrates.
• The combined system and cyclodextrin recycling provide an attractive platform for large-scale 25OHVitD3 synthesis.