Expression construct for yeast and a method of using the construct

A method of transforming yeasts by way of genome integration comprising:

• transporting a plurality of linear expression cassettes into yeasts to produce transformed yeasts with at least one copy of the cassette integrated into genome of the yeasts, wherein each of the plurality of linear expression cassettes comprises:
• a bidirectional promoter;
• a first gene and a second gene that are each operably linked to a corresponding end of the bidirectional promoter;
• a terminator located immediately next to the end of each gene;
• a 5′-Ty element and a 3′-Ty element respectively flanking 5′ end and 3′ end of the cassette to enable integration of the cassette into genome of the transformed yeast upon transporting the cassette into the yeasts;
• and
• a dominant selection marker residing within the construct and being arranged in between the flanking 5′-Ty element and the 3′-element;
• growing the yeast with a medium containing a reagent capable of reacting with a marker expressed from the dominant selection marker by the transformed yeasts to generate a signal thereof;
• and
• identifying the transformed yeasts based upon the generated signal.