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Name: Nuttawut
Status: student
Grade: 9-12
Location: Outside U.S.
Country: Thailand
Date: Winter 2012-2913

Why is yeast unable to ferment lactose?

Hi Nuttawut,

Thanks for the question. I think that yeast cannot ferment lactose since they lack the enzyme necessary to break lactose into glucose and galactose. Lactase is the name of this enzyme. Beta-galactosidase is the general family of these enzymes.

I hope this helps. Please let me know if you have any more questions. Thanks Jeff

Yeast lacks the gene that codes for lactase,an enzyme necessary to ferment lactose.

Stephen R. Dunn Ass't Professor of Medicine (ret.) Dept. Medicine/ Div. Nephrology & Cancer Genomics Kimmel Cancer Center Thomas Jefferson University

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