Cells expressing K epoxide reductase and vitamin use thereof

Cell contains and expresses a recombinant nucleic acid comprising a nucleic acid encoding vitamin K epoxide reductase (VKOR) operably associated with a heterologous promoter, wherein said nucleic acid encoding VKOR comprises SEQ ID NO: 9, or a nucleic acid which is at least 80% identical to SEQ ID NO: 9, and wherein said expressed VKOR vitamin K epoxide converted into vitamin K.