Merja Penttilä graduated 1981 from the University of Helsinki, Department of Genetics, and obtained a doctoral degree 1987. She has worked at the Technical Research Centre of Finland VTT from 1981 onwards, first as a Neste Foundation grant holder, and thereafter as a research scientist (1985-1989), senior research scientist (1989-1995) and chief scientist (1996-1999), with different group leader positions. She was nominated as a research professor in biotechnology at VTT in 1999. She is an adjunct professor (docent) in molecular genetics at the University of Helsinki (1988->). She is currently also the director of the Finnish Centre of Excellence in White Biotechnology – Green Chemistry (2008-2013).
Her research has over the years concentrated on issues relevant for industrial biotechnology and utilisation of renewable resources. The main focus has been on eukaryotic microbes, and understanding the cellular molecular functions that affect production of proteins and metabolites in these organisms. Main organisms of interest have been the filamentous fungus Trichoderma reesei and its development to an important industrial protein production host used world-wide, and metabolic engineering of yeasts for the production of e.g. bioethanol and the bioplastics precursor lactic acid.