The mammary gland bioreactor has great commercial value. The production of human recombinant proteins in milk of transgenic farm animals offers a safe, very cost-effective source of commercially proteins that cannot be produced as efficiently in adequate quantities by other methods. Based on brief illustration to the concept of mammary gland bioreactor, this review has summarized the current status of biopharmaceutical protein, vector construct, transgenic methods, economics, and obvious potential in transgenic animals bioreactors. At the same time, present problems and prospects in mammary gland bioreactor were put forward. Recently, a more powerful approach was adopted in the transgenic animals founded on the application of cloning of somatic cells, which will offer advantages and unprecedented possibilities for generating transgenic animals.
