James Edward Bailey (1944 – 9 May 2001), generally known as Jay Bailey, was an American pioneer of biochemical engineering, particularly metabolic engineering. He was said to be "the most influential biochemical engineer of modern times". In a special issue of a journal dedicated to his work, the editor said "Jay was one of biochemical engineering’s most creative thinkers and spirited advocates, a true innovator who played an enormous role in establishing biochemical engineering as the dynamic discipline it is today". His numerous contributions in biotechnology and metabolic engineering have led to multiple awards including the First Merck Award in Metabolic Engineering.