* Professor, Department of Biotechnology (May 2006 - present); IITMadras, Chennai 600036.
* Associate Professor, Department of Biotechnology (Jan. 2004 - May 2006); IITMadras, Chennai 600036.
* Assistant Professor, (Oct. 1998-Dec. 2004) Department of Chemistry, IITMadras, Chennai 600036.
* Sr. Scientist, (April 1995 - October 1998); SPIC Pharma R & D Center, Maraimalai Nagar, TN 603209.
* Scientist, (March 1991- March 1995) SPIC Pharma R & D Center, Maraimalai Nagar, TN 603 209.
* Alexander von Humboldt Fellow in Germany (April 1992 - May 1993);Study leave from SPIC.
* Research Associate, (March 1990 - March 1991)Department of Organic Chemistry, Indian Institute of Science, Bangalore 560012.
* Visiting Associate, (June 1988 - October 1989), Laboratory of Bioorganic Chemistry, Oxidation Mechanisms, National Institutes of Health, Bethesda, MD-20892, USA.
* Visiting Fogarty Fellow(June 1985 - May 1988), Laboratory of Bioorganic Chemistry, Oxidation Mechanisms, National Institutes of Health, Bethesda, MD- 20892, USA.
* Research Fellow, (July 1979 - December 1984), Indian Institute of Science, Bangalore.
* Lecturer, (June 1978 - May 1979), Department of Chemistry, Fergusson College, University of Poona, Poona, India.
* Jan. 2005-2007; Tata Chemicals Ltd.
* Dec. 2004-March 2005, Retainer Consultancy with Matrix Laboratories,Hyderabad
* April, 2004-December 2005, Research Based Industrial Consultancy with Tata Chemicals Ltd. Mumbai
* September, 2003-September 2004, Research Based Industrial Consultancy with MDPL, Chennai
* May, 2001-Dec., 2002; consultant with Thirumalai Chemicals, Chennai to set up some Biocatalysed Industrial Processes; visited Czech and Slovak Republics as an expert to evaluate a process involving a bioconversion for technology transfer, (7-20 Sept., 2001)
* October 1994 – July 1995, consultant for the project entitled Preparation of optically pure (S)Ibuprofen using chemoenzymatic methods, conducted jointly by the Center for Biotechnology, Anna University and Shasun Chemicals, Chennai.
* Life member of the Indian Society of BioOrganic Chemists (ISBOC)
* Life member of the Chemical Research Society of India (CRSI)
* Life member of the IISc Alumni Association, Bangalore
* Elected Fellow of the Madras Science Foundation
* Member, TIFAC, DST, Project Monitoring Committee, 2008 onwards
* Member, DSIR, Project Review Committee 2007-present
* Member, Subject Expert Committee, WOS-A, DST (2004-2007)
* Member Secretary, IITM Ethics Committee (2006-present)