Department of Biotechnology and Biomedicine

Lone Gram's web-page

Education and employment

Professor at the Department for Systems Biology (2013-), Technical University of Denmark, at DTU National Food Institute (2010-2012), at DTU Aqua and DTU SystemBiology (2005-2010) and at the Danish Institute for Fisheries Research (2000-2005).

Received the Fritz Kaufmann Mindefond award (2008) and Tagea Brandt travel award (2008)

Visiting research scientist in 2009 at Professor Roberto Kolter's group at Harvard Medical School, Boston, USA and in 1994-95 and 1999 at Professor Staffan Kjelleberg's group at University of New South Wales, Australia.

External associate professor at the RVAU 1989-2000. Consultancies for the Food and Agricultural Organization of the United Nations (FAO) on projects and courses related to fish technology

Member (1998-2007) and secretary (2003-2007) of ICMSF; the International Commission on Microbiological Specifications for Foods (revised March 2007)

M.Sc. in food science (1980-1985) and Ph.D. (1989) from the Royal Veterinary and Agricultural University (RVAU)

Chairman of the Danish Research Council for Natural Sciences (2015-), vice chair (2014) and member (2013-). Editor of Applied and Environmental Microbiology (2006-2012), member of the Danish Council for Research Policy (2007-2011)

In 2006, I joined a global scientific marin cruise (Galathea3) where we determined the distribution of culturable bacteria with antibacterial activity in the marine environment . Specifically, we have searched for organisms belonging to the Roseobacter clade but our work has also demonstrated that Pseudoalteromonas spp. and Vibrio spp. have inhibitory properties. This work can potentially be of interest in drug discovery work. A short Danish description of the project is available.

The research of my group aims at developing and using novel antibacterial principles to control pathogenic bacteria. We also assess impact and physiological effects on pathogenic bacteria of known and novel antibacterials. In part, novel antibacterials are derived from (marine) bacteria and we use bacteria with desired characteristics (probiotics, producers of bioactive compounds) in our quest to control bacteria that are pathogenic either to man or to fish. Below is  brief list of topics and articles related to work in the group. You can find a description of the Bacterial Ecophysiology and Biotechnology Group


Novel antibacterial compounds. We have a constant need for controlling unwanted bacteria - be it infectious or spoiling microorganisms. We spend a vast amount of our time removing or killing bacteria; washing, cleaning, disinfecting, in food preservation - and in treatment of infectious diseases. We have worked with a multitude of novel antibacterial compounds - bacteriocins, antimicrobial peptides, enzymes and compounds affecting quorum sensing. We are currently (2013) focusing on antibacterial compounds produced by marine bacteria and the use of antimicrobial peptides.


Fish probiotics and interactions between marine bacteria. An ever increasing amount of fish is being produced in aquaculture - today almost 50% of fish used for human consumption are farmed. Although vaccines have been tremendously succesful as disease control measures, antibiotics are still used against several bacterial fish diseases. Due to the concerns raised vis-a-vis development of antibiotic resistance, alternative disease control measures must be sought. Probiotics (live microbial cultures which when supplied to the host confers a beneficial effect) have, in some scenarios, been succesful. We are currently especially interested in the potential of marine Roseobacter as fish larval probiotics. We collaborate with German, Norwegian, Greek and American research groups on this organism


Listeria monocytogenes - ecology and virulence. Listeria monocytogenes is an important food-borne pathogen that, in high risk population groups, can cause the serious infectious disease, listeriosis. The disease is typically transmitted with ready-to-eat food products in which the organism has grown to high numbers. We study all aspects related to measures than can control the organism. This includes its prevalence in the environment, its persistance in food processing, its biofilm formation, prevention of growth using bioprotection - and recently also its interaction with eucaryotic cells and hosts. We have projects both at the very applied level - working with the fish processing industry - and at a more basic scientific level where we collaborate with several Danish and international research groups.


Hygiene and biofilms. In the environment most bacteria will grow adhered to surfaces and not as free living cells. The ability to grow at surfaces as biofilms is also important in food processing environments. We have studied the biofilm formation and the subsequent enzymatic removal of biofilms by several methods. These studies are continued in collaboration with several Danish research institutes and industries in which we study the adherence and biofilm formation of the food borne pathogen Listeria monocytogenes. We have, in model systems  evaluated different surface modifications and have determined the effect of surface roughness (of stainless steel) on bacterial adhesion. On an industrial scale, we have compared different types of disinfection processes with respect to effect on hygienic level in general, on on Listeria monocytogenes. We have demonstrated that surface coatings (e.g. fish extracts) can be used to reduce bacterial adhesion withing interfering with growth of the bacterial cell. We collaborate with several Danish and international research groups.


Quorum related interactions between bacteria on fish and in fish products. Bacteria will through antagonistic and synergistic activities interact and influence the growth and metabolism of one another. Many pathogenic bacteria and symbiotic bacteria employ acylated homoserine lactones (AHLs) in cell-to-cell communication. This communication enables them to coordinate gene expression, e.g. toxin production, in a population. We have assessed the importance of AHL communication in food spoilage and the effect of specific quorum sensing inhibtiors (QSIs). We also study AHL-signalling in fish pathogenic bacteria and have demonstrated that compounds interfereing with AHL-systems (so-called quorum sensing inhibtors) reduce vibriosis mortality in rainbow trout. Studies on AHL signalling and QSI compounds were carried out in close collaboration with Professor Michael Givskov at KU-SUND and Dr. Kristian Fog Nielsen at Systems Biology at the Technical University of Denmark. Currently, we collaborate with the Feed Research Institute of the Chinese Academy of Agricultural Sciences on QS in fish pathogens and the potential use of QSIs.


Ecology and detection of Shewanella putrefaciens . The spoilage of aerobically stored iced fish is mainly caused by growth and metabolism of S. putrefaciens. We have used the spoilage reactions (e.g. reduction of trimethylamine oxide and production of H2S or antibody technology for specific detection of this organism. S. putrefaciens is able to use many compounds, including Fe3+, as electron acceptors. We have shown that during aerobic respiration, S. putrefaciens uses specific iron chelators, so-called siderophores, for iron uptake  and that fish based substrates are well suited for detection of siderophore production by several bacteria. Many mesophilic strains formerly identified as S. putrefaciens belong to a different species, Shewanella algae which may cause wound infections and bacteremia in humans. S. algae is a marine bacterium and can be detected in Danish marine waters when the water temperature is above 15°C. Our work has, in collaboration with American collegues, led to the identification of several new Shewanella species


Novel antibacterial compounds

Giubergia et al. 2015.  Int. J. System. Evol. Microbiol. (accepted)

Citterio et al. 2015. Res. Microbiol. (accepted)

Gottschalk et al. 2015. J. Med Microbiol (accepted)

Machado et al. 2015. Int. J. System. Evol. Microbiol. (accepted)

Le Roux et al. 2015. Front in Microbiol. 6:830

Machado and Gram 2015. Appl. Environm. Microbiol. 81: 2745-2752

Machado et al. 2015 BMC Genomics 16:158

Gram, L 2015. Microb. Biotechnol. 8:13-14

Harrington et al. 2014. Marine Drugs 12:5960-5978

Rasmusen et al. 2014. Marine Drugs. 12:5527-5546

Bentzon-Tilia et al. 2014. Gen. Announcement. 2:e01213-14

Machado et al. 2014. Gen. Announcement. 2:e00535-14

Rabe et al. 2014. Beilstein J. Org. Chem  10:1796–1801

Andreev et al. 2014. BBA Biomembranes 1838:2492–2502

Kjaerulff et al. 2014. Mar Drugs 11:5051-5062

Neu et al. 2014. Appl. Environ. Microbiol. 80:146-153

Nielsen et al. 2014. PLoS One 9:e84992

Kjaerulff  et al. 2013.Mar. Drugs. 11:5051-5062

Gottshalk et al. 2013. BMC Microbiology 13:92

Hein-Kristensen et al. 2013. Res. Microbiol. 164:933-940

Hein-Kristensen et al. 2013. PloS ONE 8:e73620

Maatoft-Udsen et al. 2013. Innate Immun. 19:160-173

Nielsen et al. 2012. Mar. Drugs 10:2584-2595

Vynne et al. 2012. Mar. Drugs 10:1729-1740

Wietz et al. 2012 Appl. Environ. Microbiol. 78:2039-2042

Hein-Kristensen et al. 2011 BMC Microbiol 11:144

Wietz et al. 2011. Env Microbiol Rep 3:559-564

Vynne et al. 2011 Mar Biotechnol. 6:1062-1073

Månsson et al. 2011 Mar Drugs 9:1440-1468

Månsson et al. 2011 Mar Drugs 9:2537-2552

Thomsen et al. 2010. BMC Microbiol. 10:307

Wietz et al. 2010. Mar Drugs 8:2946-2960

Wietz et al. 2010. Aquat. Microb. Ecol. 61:179-189

Månsson et al. 2010 J. Nat. Prod. 73:1126-1132

Gram et al. 2010 Mar. Biotechnol. 12:439-451

Gottlieb et al. 2008 BMC Microbiol. 8:205

Hansen et al 2005. J. Appl. Microbiol. 98:581-588

Nilsson et al. 2002. Appl. Environ. Microbiol. 68:2251-2260


Fish probiotics and interactions between marine bacteria.

D'Alvise et al. 2015. Appl. Environ. Microbiol. (accepted)

Gram et al. 2015 System. Appl. Microbiol. 38:483-493

Prol-Garcia et al. 2014. J. Appl. Microbiol. 117:1592-1600

Tan et al. 2014. Appl Environ. Microbiol.80:3128-3140

D'Alvise et al. 2014. Environ. Microbiol. 16:1252-1266

Bernbom et al. 2013. Appl. Environ. Microbiol. 79:6885-6893

Prol-Garcia et al. 2013. Appl. Environ. Microbiol. 79:5414-5417

D'Alvise et al.  2013. Aquaculture 384:82-86

D'Alvise et al. 2012. PLoS One 7:e43996

Bernbom et al. 2011. Appl. Environ. Microbiol. 77:8557-8567

Porsby et al. 2011. Antimic. Ag. Chemother. 55:1332-1337

D'Alvise et al. 2010. Appl. Environ. Microbiol 76:2366-2370

Prol et al. 2009. J. Appl. Microbiol. 106:1292-1303

Porsby et al. 2008. Appl. Environ. Microbiol. 74:7356-7354

Geng et al. 2008 Appl. Environ. Microbiol 74:1535-1545

Bruhn et al. 2007 Appl. Environ. Microbiol. 73:442-450

Bruhn et al. 2006 Appl. Environ. Microbiol. 72:3011-3015

Planas et al. 2006 Aquaculture 255:323-333

Bruhn et al. 2005 Appl. Environ. Microbiol. 71:7263-7270

Hjelm et al. 2004 Syst. Appl. Microbiol. 27:360-371

Hjelm et al. 2004 Appl. Environ. Microbiol. 70:7288-7298

Huber et al. 2004 J. Appl. Microbiol. 96:117-132

Spanggaard et al. 2001 Env. Microbiol. 3:755-765

Gram et al. 1999 Appl. Environ. Microbiol. 65:969-973


Listeria monocytogenes - ecology and virulence  

Lauersen et al. 2015. Env. Microbiol. 17:1134-1151   

Kastbjerg et al. 2014. Antimicr. Ag. Chemother. 58:3124-3132

Knudsen et al. 2013. Appl. Environ. Microbiol. 79:7390-7397

Holch et al. 2013. J. Med. Microbiol. 62:1799-1806

Nielsen et al. 2013. BMC Microbiology 13(1):177

Holch et al. 2013. Appl. Environm. Microbiol. 79:2944-2851

Kastbjerg and Gram. 2012 Int. J. Food Microbiol. 160: 11-15

Knudsen et al. 2012 J. Appl. Microbiol. 113:1275-1286

Feld et al.  Appl. Environ. Microbiol. 78:4353-4357

Holch et al. 2010. Appl Environ. Microbiol. 76:3391-3397

Kastbjerg et al. 2010. Appl. Environ. Microbiol. 76:303-309

Kastbjerg et al. 2009. Appl. Environ. Microbiol. 75:4550-4556

Jensen et al. 2008 Int. J. Food Microbiol. 123:254-261

Jensen et al. 2008 J. Food Prot. 71:1028-1034

Jensen et al. 2007 J. Food Prot. 70:592-599

Hansen et al. 2006 J. Food Prot. 69:2113-2122

Vogel et al. 2006 J. Food Prot. 69:2134-2142

Wulff et al. 2006 Appl. Environ. Microbiol. 72:4313-4322

Alves et al. 2005 J. Food Prot. 68:2068-2077

Bruhn et al. 2005 Appl. Environ. Microbiol. 71:961-967

Nilsson et al. 2005 J. Appl. Microbiol. 98:172-183

Nilsson et al. 2004 J. Appl. Microbiol. 96:133-143

Martinez et al. 2003 Int. J. Food Microbiol. 84:285-297

Vogel et al. 2001 Appl. Environ. Microbiol. 67:2586-259


Hygiene and biofilms.

Meyer et al. 2013. Coll. Surf. B: Biointerfac. 102:504-510

Christensen et al. 2011 Ant. Ag. Chemother 55:4064-4071

Bernbom et al. 2011. Int. J. Food Microbiol. 147:69-73

Vogel et al. 2010. Int. J. Food Microbiol. 140:192-200

Kastbjerg and Gram 2009. J. Appl. Microbiol. 106:1667-1681

Bernbom et al. 2009. J. Appl. Microbiol. 106:1268-1279

Vejborg et al 2008 J. Appl. Microbiol. 105:141-150

Bernbom et al. 2006 Biofilms 3:25-36

Gram et al. 2007 Food Control 18:1165-1171

Hansen et al. 2004  Appl. Environ. Microbiol. 70:1749-1757

Bagge-Ravn et al. 2003 J. Food Prot. 66:592-598

Hansen et al. 2003 Appl. Environ. Microbiol.  69:4611-4617

Hilbert et al. 2003 Int. J. Biodet. Biodegr. 52:175-185

Kingshott et al. 2003 Langmuir 19:6912-6921

Wei et al. 2003 Colloids and Surfaces B:Biointeractions 32:275-291

Bagge et al. 2001 Appl. Environ. Microbiol. 67:2319-2325

Johansen et al. 1997 Appl. Environ. Microbiol. 63:3724-3728


Quorum related interactions between bacteria on fish and in fish products.  

Rasmussen et al. 2014. Mar. Drugs 12:5527-5546

Sweinteit et al. 2011. Vet. Microbiol. 147:389 - 397

Valiente et al. 2009 FEMS Microbial Ecol. 69:16-26

Kastbjerg et al. 2007  J. Appl. Microbiol. 102:363-374.

Rasch et al. 2007 Dis. Aquat. Org. 78:105-113

Buchholtz et al. 2006 Syst. Appl. Microbiol. 29:433-445

Bruhn et al. 2005 Dis. Aquat.Org. 65:43-52

Flodgaard et al. 2005. Appl. Environ. Microbiol. 71:2113-2120

Rasch et al. 2005 Appl. Environ. Microbiol. 71:3321-3330

Bruhn et al. 2004 Appl. Environ. Microbiol. 70:4293-4302

Buch et al. 2003 Syst. Appl. Microbiol. 26:338-349

Rasch et al. 2003 Syst. Appl. Microbiol. 27:350-359

Gram et al. 2002 Int. J. Food Microbiol. 78:79-97

Ravn et al. 2001 J. Microbiol. Methods 44:239-251


Ecology and detection of Shewanella putrefaciens .

Satomi et al. 2007 Int. J. System. Evol. Microbiol. 57:347-352

Satomi et al. 2006 Int. J. System. Evol. Microbiol. 56:243-249

Vogel et al. 2005 Appl. Environ. Microbiol. 11:6689-6697

Gram et al. 1999 Appl. Environ. Microbiol. 65:3896-3900

Vogel et al. 1997 Appl. Environ. Microbiol. 63:2189-2199

Gram 1996 J. Microbiol. Meth. 25:199-205

Gram 1994 Appl. Environ. Microbiol. 60:2132-2136

Gram 1992 Int. J. Food Microbiol. 16:25-39

Last updated 12.11.2015