Human Intrinsic Factor Expression for Bioavailable Vitamin B(12) 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(12) (B(12)). Microalgae are making their way into the dietary supplement and functional food market but do not produce B(12), and their B(12) content is very variable. In this study, the suitability of using the human B(12)-binding protein intrinsic factor (IF) to enrich bioavailable B(12) using microalgae was tested. The IF protein was successfully expressed from the nuclear genome of the model microalga Chlamydomonas reinhardtii and the addition of an N-terminal ARS2 signal peptide resulted in efficient IF secretion to the medium. Co-abundance of B(12) and the secreted IF suggests the algal produced IF protein is functional and B(12)-binding. Utilizing IF expression could be an efficient tool to generate B(12)-enriched microalgae in a controlled manner that is suitable for vegetarians and, potentially, more bioavailable for humans.