One-Pot Synthesis of Useful S-Substituted-l-cysteine Sulfoxides Using Genetically Engineered Escherichia coli

Area of Science:

• Biotechnology
• Enzymatic Synthesis
• Metabolic Engineering

Background:

• S-Substituted-l-cysteine sulfoxides, like (+)-alliin, are plant-derived compounds recognized for their health benefits.
• Current production methods (extraction and chemical synthesis) face limitations in stability and safety.
• There is a need for efficient and scalable methods for producing these valuable compounds.

Purpose of the Study:

• To develop an enzymatic cascade reaction for the one-pot synthesis of (+)-alliin.
• To engineer Escherichia coli for efficient biocatalysis of (+)-alliin production.
• To explore the synthesis of diverse S-substituted-l-cysteine sulfoxides using the developed bioprocess.

Main Methods:

• Constructed engineered Escherichia coli coexpressing tryptophan synthase and l-isoleucine hydroxylase.
• Optimized reaction conditions for (+)-alliin accumulation.
• Investigated the synthesis of various S-substituted-l-cysteine sulfoxides by introducing different thiols.

Main Results:

• Engineered E. coli achieved a 2-fold increase in yield after tryptophanase gene deletion.
• Optimized conditions led to a record accumulation of 110 mM (+)-alliin.
• The bioprocess successfully synthesized a range of natural and unnatural S-substituted-l-cysteine sulfoxides.

Conclusions:

• The developed enzymatic cascade reaction provides a highly productive and scalable bioprocess for (+)-alliin synthesis.
• This method overcomes the limitations of traditional production techniques.
• The platform enables the production of diverse S-substituted-l-cysteine sulfoxides, expanding their availability for research and application.