Described herein is an engineered Kluyveromyces marxianus cell, the cell comprising in its genome: (i) two different nucleic acid molecules that each contain a promoter operably linked to a gene encoding a functional enzyme, and (ii) a selection nucleic acid molecule that contains a promoter operably linked to a gene encoding a selectable marker, wherein all of the nucleic acids molecules of (i) and (ii) are in tandem and the engineered cell expresses all of the proteins encoded by the genes of (i) and (ii).
