He worked as a postdoctoral researcher in the United States (1972-75), and with the Nobel laureate Severo Ochoa at the New York University and the Roche Institute of Molecular Biology in New Jersey.
In 1975 he joined the CSIC Instituto de Microbiología Bioquímica in Salamanca, from where he proceeded to the Complutense University, obtaining the Chair of Microbiology in the Faculty of Pharmacy in 1981.
His research in Microbial Molecular Biology and Biotechnology has focused on model organisms, addressing cell wall biogenesis, signal transduction in the cell, pathogenicity and virulence factors, and applications relating to the production of recombinant proteins. Key aspects of his work are the use of genomics and proteomics technology, and since 2001 he has directed the first extraordinary chair of Genomics and Proteomics at a Spanish university (sponsored by Merck, Sharp & Dohme).
He has written over 140 original research papers, supervised more than 25 doctoral theses, and has also published popular science articles and public debates in areas such as bioethics, university policy and science policy.
He has held important positions in foundations, and was appointed President of the "Fundación Carmen and Severo Ochoa" in the Nobel laureate’s will. Member of several scientific societies, he has presided the Spanish Society for Microbiology (1982-90) and the Federation of European Microbiological Societies (1995-98). He has also sat on the UNESCO’s International Bioethics Committee (1998-2003) and in Spain, he was President of the "Advisory Committee on Ethics in Science and Technology Research" (2002-2005). He is a member of the European Academy and the Royal Academy of Pharmacy (2007).
Among other accolades, he holds the Grand Cross of the Order of Civil Merit (2001) and gold medals from the Universities of Lleida (2000) and Castile-La Mancha (2001).