Human Intrinsic Factor Expression for Bioavailable Vitamin B Enrichment in Microalgae.

Dietary supplements and functional foods are becoming increasingly popular complements to regular diets. A recurring ingredient is the essential cofactor vitamin B (B). Microalgae are making their way into the dietary supplement and functional food market but do not produce B, and their B content is very variable. In this study, the suitability of using the human B-binding protein intrinsic factor (IF) to enrich bioavailable B using microalgae was tested. The IF protein was successfully expressed from the nuclear genome of the model microalga and the addition of an N-terminal ARS2 signal peptide resulted in efficient IF secretion to the medium. Co-abundance of B and the secreted IF suggests the algal produced IF protein is functional and B-binding. Utilizing IF expression could be an efficient tool to generate B-enriched microalgae in a controlled manner that is suitable for vegetarians and, potentially, more bioavailable for humans.