51cg

Professor Alan Walker

Professor Alan Walker
Professor Alan Walker
Professor Alan Walker

Chair in Microbiome Science

51cg
Email Address
alan.walker@abdn.ac.uk
Telephone Number
+44 (0)1224 438739
Office Address
5.050 The Rowett Institute
Foresterhill Campus
Foresterhill
AB25 2ZD

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School/Department
School of Medicine, Medical Sciences and Nutrition




Biography

I am a microbiologist by training with specific research interests in the bacteria that inhabit the gastrointestinal tract of mammalian hosts.

After receiving an undergraduate degree in Microbiology from the 51cg I studied for my PhD at the Rowett Institute and at the University of Dundee, specialising in gut microbiology and the role that intestinal bacteria play in the breakdown of dietary fibre. I then spent eight and a half years at the Wellcome Sanger Institute in Cambridge, a renowned centre for genomics research. While there I used state of the art DNA sequencing facilities to better characterise host-associated microbial communities and shed light on the roles these microbes play both in health and in diseases such Cystic Fibrosis, inflammatory bowel disease and infection with Salmonella spp. and Clostridium difficile.

I am now a Professor (Personal Chair) at the Rowett Institute within the 51cg. In our lab we combine anaerobic microbiology with DNA sequencing technologies in order to examine interactions between host diet and the intestinal microbiota of humans and animals, and how these factors may contribute to host health.

Qualifications

  • PhD Gut Microbiology 
    2006 - University of Dundee 
  • BSc (Hons) Microbiology 
    2001 - 51cg 

Memberships and Affiliations

Internal Memberships

Postgraduate Research Coordinator for the Rowett Institute - 2024 to Present

51cg Foresterhill Biological Safety Committee member - 2022 to Present.

External Memberships

Editorial Roles:

Microbiome (2013 – 2017) [Editorial Board member then Associate Editor]

Microbial Genomics (2015 – 2024) [Senior Editor to Jan. 2022, then Editor]

 

Grant Panel Member:

The Deutsche Forschungsgemeinschaft (German Research Foundation) (x2)

BBSRC Tools and Resources Development Fund

BBSRC Institute Assessment Exercise

BBSRC Responsive Mode Committee A (x5)

European Commission Joint Programming Initiative

 

Committee/Advisory Board Member:

ComMet – Community Network in Metagenomics (BBSRC funded initiative), 2014-2018.

EnteroBiotix Ltd – Independent Scientific & Medical Advisory Board member, 2015-2020.

BBSRC Microbiome Expert Working Group, 28/9/16 and 15/11/16.

BBSRC Pool of Experts (Microbiome), 2018-2021.

Core Membership of BBSRC Research Committee A, 1/1/2022 to 31/3/2025.

KTN Microbiome Biobanking Group, 2021-2022.

Earlham Institute Scientific Advisory Board, 2024-2027

 

Prizes and Awards

Clarivate (Web of Science) highly cited researcher: 2019, 2020, 2021, 2022, 2023 and 2025.

Team member – “Outstanding Research Team”, awarded to the Rowett Gut Microbiology Group, 51cg Excellence Awards, 2023.

Team member – Runner up, “Nature/Yakult Global Grants for Gut Health Research Group Prize 2023”, awarded to the Rowett Gut Microbiology Group.

Research

Research Overview

Microbiota research has been revolutionised in recent years by the advent of modern DNA sequencing technologies. These allow large-scale, in-depth studies, greatly expanding our ability to monitor the microbiota and how it responds to host behaviour such as changes in diet. However, traditional microbiology techniques such as anaerobic culture also remain highly relevant, and help us to understand the functional roles that individual members of the microbiota may play in the intestines. In our lab we combine DNA sequence analysis and microbiological approaches to generate novel insights into the intestinal microbiota of humans and animals. 

Current Research

Much of our current research interests are in identifying key functional groups of bacteria within the intestinal microbiota of humans and animals. Although intestinal microbiotas are extremely complex entities, with many species sharing overlapping functional capabilities, it is thought that some deleterious or beneficial activities are limited to a relatively small range of species. In particular, we are interested in microbial contributors to the development of chronic ailments. For example, we are interested in bacterial consumers of lactate, accumulation of which has been linked to chronic diseases such as inflammatory bowel disease, and producers of trimethylamine (TMA), which has been linked to cardiovascular disease. We are also interested the role that host diet plays in the prevalence and activities of these key functional gut bacterial groups.

In addition, we study the role that the intestinal microbiota plays in inhibiting pathogenic microbes. We use the Rowett Institute's extensive collection of gut bacteria to screen for individual strains that show activity against a range of important pathogens of humans and animals. We are also members of the EU-funded , as part of which we are particularly interested in identifying specific microbes, and mechanisms, involved in antagonistic activity against the fungal pathogen Candida albicans in the colon.  

We are also part of GCRF-funded , which involves partners from many different countries, where we are carrying out research to investigate how the microbes that are present in the intestines of children in low to middle income countries might play a role in their risk of developing stunting.

Ultimately, the unifying goal across all of these projects is to determine key functional groups of gut bacteria, which is a critical step towards developing microbiota-based therapeutics for use in humans and animals.

 

Research Team:

– Research Assistant

Dr Anouschka Ramsteijn - Postdoctoral Research Fellow

 - Honorary Research Fellow

Dr Eva Soto-Martin - Postdoctoral Research Fellow

 

 

Previous Group Members:

Research Assistants:

- April 2014 to March 2021

Postdocs:

Dr Galiana Lo - Jan 2023 to Dec 2023

Dr Indrani Mukhopadhya - Oct 2020 to Nov 2022

 - May 2015 to Nov 2017

 -  Feb 2019 to Dec 2020

PhD Students:

 - PhD Student

 - PhD Student

- PhD Student

Visiting PhD Students:

Margot Delavy (Institut Pasteur) - Mar to Apr 2022

(Palacký University Olomouc) – Aug to Nov 2018

(Instituto de Investigación en Ciencias de La Alimentación) – April to July 2017

MSc Students:

Jesmine Costa - May to Aug 2025

Alison Eastick - May to Aug 2023

Abdulelah Aljadani - May to Aug 2023

Bonface Gichuki - May to Aug 2022

Sharon Johnson - May to Nov 2021

- Jan 2020 to July 2020

Noburo Kato - March 2019 to July 2019

- April 2018 to July 2018

- April 2017 to July 2017

- April 2017 to July 2017

- April 2016 to July 2016

- April 2015 to July 2015

Collaborations

We are aided in our work by long standing collaborations with many other international research groups. We also have links to industry, including companies such as  and .

 

Funding and Grants

Selected Ongoing Projects:

2022-2027       Harnessing the gut microbiome to strengthen livestock resilience against carriage and infection by pathogens. Scottish Government's Rural and Environmental Science and Analysis Service (RESAS). [PI].

2022-2027       Incorporation of whole ecosystem approaches to reduce transmission of foodborne pathogens and antimicrobial resistance. RESAS. [Co-I: Karen Scott is PI].

2022-2026       Developing delivery strategies for next generation probiotics and microbiome therapeutics. RESAS PhD Studentship. [Co-I: Karen Scott is PI].

2019-2024       Action Against Stunting Hub. UKRI GCRF. [Co-I: Claire Heffernan is PI].

2019-2024       FunHoMic: Deciphering the fungus-host-microbiota interplay to improve the management of fungal infections. European Commission. [Co-I: Christophe d'Enfert is PI].

 

Selected Past Funding:

2020-2023       EnteroBiotix KTP. Innovate UK/Enterobiotix. [PI].

2014-2022       Supported by core institutional funding for the Rowett Institute. RESAS. [PI].

2017 - 2021     MECNUT: Impact of dietary exposure to emulsifiers on the intestinal mucosa - implications for inflammatory bowel disease and metabolic syndrome. MRC. [Co-I: Barry Campbell was PI]

2016-2020       Mechanisms underpinning the links between diet, the intestinal microbiota and health. Princess Royal Tenovus Scotland Medical Research Scholarship. [PI]

2016-2020       Uncovering the impact of diet-responsive gut microbes on host health.  RESAS PhD Studentship. [PI]

2016-2019       Microbiome and metagenomic study of the rumen microbial population and their microbial enzyme genes. RESAS. [PI]

2015-2017       Exploiting the microbiome to prevent and treat human diseasesChr. Hansen. [Co-PI with Harry Flint]

2015                Impact of the gut microbiota and diet upon Candida colonisation and infectionWellcome Trust ISSF@Aberdeen Seed Corn award. [Co-I: Al Brown was PI].

2011-2014       Immunological and microbiological effects of fecal transplantation in chronic pouchitisBroad Foundation. [Co-I: Ailsa Hart was PI]

2010-2014       Microbial community ecology of chronic respiratory infectionsNERC CASE Studentship. [Co-I: Christopher van der Gast was PI]

2011-2013       The gut microbiota and NOD2 genotype in Crohn’s disease: a pilot study for the UKIBD Microbiota ConsortiumCore – The Digestive Disorders Foundation. [Co-I: Charlie Lees was PI].

 

Teaching

Teaching Responsibilities

  • Joint course co-ordinator: Honours Microbiology, MC4014 (2023-Present). Deputy course co-ordinator from 2020 to 2023.

 

Lectures/Tutorials:

MSc

  • Molecular Nutrition, RR5502
  • Introduction to Microbiology, MC5008
  • Genes and Immunity, MB5526
  • Clinical Nutrition for Disease Prevention, PU5541
  • Challenges in Global Nutrition, PU5547

Undergraduate

  • Honours Microbiology, MC4014
  • Molecular Microbiology, MC3504

Other

  • Mothur Workshop (Bioinformatics training workshop) 

 

Associate Fellow of the Higher Education Authority – June 2015 to Present

Publications

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  • Microbial lactate utilisation and the stability of the gut microbiome

    Louis, P., Duncan, S., Sheridan, P., Walker, A., Flint, H. J.
    Gut Microbiome, vol. 3, e3
    Contributions to Journals: Articles
  • Higher total faecal short-chain fatty acid concentrations correlate with increasing proportions of butyrate and decreasing proportions of branched-chain fatty acids across multiple human studies

    Scott, K., LaBouyer, M., Holtrop, G., Horgan, G., Gratz, S., Belenguer, A., Smith, N., Walker, A., Duncan, S., Johnstone, A., Louis, P., Flint, H. J.
    Gut Microbiome, vol. 3, e2
    Contributions to Journals: Articles
  • Antimicrobial effects of synthetic phenolic antioxidants on dietary fibre degrading bacteria

    Shallangwa, S., Morgan, P. J., Walker, A. W., Ross, A. W.
    Proceedings of the Nutrition Society, vol. 81, no. OCE1, 47
    Contributions to Journals: Abstracts
  • Distribution, organization and expression of genes concerned with anaerobic lactate utilization in human intestinal bacteria

    Sheridan, P., Louis, P., Tsompanidou, E., Shaw, S., Harmsen, H. J. M., Duncan, S., Flint, H. J., Walker, A.
    Microbial Genomics, vol. 8, no. 1, 000739
    Contributions to Journals: Articles
  • Dietary fibre complexity and its influence on functional groups of the human gut microbiota

    Louis, P., Solvang, M., Duncan, S., Walker, A., Mukhopadhya, I.
    Proceedings of the Nutrition Society, vol. 80, no. 4, pp. 386–397
    Contributions to Journals: Articles
  • Description of Ruminococcoides bili gen. nov., sp. nov., a bile resistant bacterium from human bile with autolytic behavior.

    Molinero, N., Conti, E., Sánchez, B., Walker, A. W., Margolles, A., Duncan, S. H., Delgado, S.
    International Journal of Systematic and Evolutionary Microbiology, vol. 71, no. 8, 004960
    Contributions to Journals: Articles
  • The impact of the Fungus-Host-Microbiota interplay upon Candida albicans infections: current knowledge and new perspectives

    d'Enfert, C., Kaune, A., Rey Alaban, L., Chakraborty, S., Cole, N., Delavy, M., Kosmala, D., Marsaux, B., FróisMartins, R., Morelli, M., Rosati, D., Valentine, M., Xie, Z., Emritloll, Y., Warn, P. A., Bequet, F., Bougnoux, M., Bornes, S., Gresnigt, M. S., Hube, B., Jacobsen, l. D., Legrand, M., Leibundgut-Landmann, S., Manichanh, C., Munro, C., Netea, M. G., Queiroz, K., Roget, K., Thomas, V., Thora, C., Van den Abbeele, P., Walker, A. W., Brown, A. J.
    FEMS Microbiology Reviews, vol. 45, no. 3, fuaa060
    Contributions to Journals: Review articles
  • Exclusive enteral nutrition mediates gut microbial and metabolic changes that are associated with remission in children with Crohn’s disease

    Diederen, K., Li, J. V., Donachie, G. E., de Meij, T. G., de Waart, D. R., Hakvoort, T. B. M., Kindermann, A., Wagner, J., Auyeung, V., te Velde, A. A., Heinsbroek, S. E. M., Benninga, M. A., Kinross, J., Walker, A. W., de Jonge, W. J., Seppen, J.
    Scientific Reports, vol. 10, pp. 18879
    Contributions to Journals: Articles
  • Relative abundance of the Prevotella genus within the human gut microbiota of elderly volunteers determines the inter-individual responses to dietary supplementation with wheat bran arabinoxylan-oligosaccharides

    Chung, W. S. F., Walker, A., Bosscher, D., Garcia-Campayo, V., Wagner, J., Parkhill, J., Duncan, S., Flint, H. J.
    BioMed Central Microbiology, vol. 20, 283
    Contributions to Journals: Articles
  • Pivotal roles for pH, lactate and lactate-utilizing bacteria in the stability of a human colonic microbial ecosystem

    Wang, S. P., Rubio, L. A., Duncan, S. H., Donachie, G. E., Holtrop, G., Lo, G., Farquharson, F. M., Wagner, J., Parkhill, J., Louis, P., Walker, A., Flint, H. J.
    mSystems, vol. 5, no. 5, e00645-20
    Contributions to Journals: Articles
  • The environmental stress sensitivities of pathogenic Candida species, including Candida auris, and implications for their spread in the hospital setting

    Heaney, H., Laing, J., Paterson, L., Walker, A. W., Gow, N. A., Johnson, E. M., MacCallum, D. M., Brown, A. J. P.
    Medical Mycology, vol. 58, no. 6, pp. 744-755
    Contributions to Journals: Articles
  • Analysis of 1321 Eubacterium rectale genomes from metagenomes uncovers complex phylogeographic population structure and subspecies functional adaptations

    Karcher, N., Pasolli, E., Asnicar, F., Huang, K. D., Tett, A., Manara, S., Armanini, F., Bain, D., Duncan, S. H., Louis, P., Zolfo, M., Manghi, P., Valles-Colomer, M., Raffaetà, R., Rota-Stabelli, O., Collado, M. C., Zeller, G., Falush, D., Maixner, F., Walker, A. W., Huttenhower, C., Segata, N.
    Genome Biology, vol. 21, 138
    Contributions to Journals: Articles
  • Lung function and microbiota diversity in cystic fibrosis

    Cuthbertson, L., Walker, A. W., Oliver, A. E., Rogers, G. B., Rivett, D. W., Hampton, T. H., Ashare, A., Elborn, S., De Soyza, A., Carroll, M., Hoffman, L. R., Lanyon, C., Moskowitz, S., O'Toole, G., Parkhill, J., Planet, P. J., Teneback, C., Tunney, M., Zuckerman, J., Bruce, K. D., van der Gast, C.
    Microbiome, vol. 8, 45
    Contributions to Journals: Articles
  • Application of the Dynamic Gastrointestinal Simulator (simgi®) to assess the impact of probiotic supplementation in the metabolism of grape polyphenols

    Gil-Sánchez, I., Cueva, C., Tamargo, A., Quintela, J. C., de la Fuente, E., Walker, A. W., Moreno-Arribas, M. V., Bartolomé, B.
    Food Research International, vol. 129, 108790
    Contributions to Journals: Articles
  • Food additives: Assessing the impact of exposure to permitted emulsifiers on bowel and metabolic health – introducing the FADiets study

    Partridge, D., Lloyd, K. A., Rhodes, J. M., Walker, A. W., Johnstone, A. M., Campbell, B. J.
    Nutrition Bulletin, vol. 44, no. 4, pp. 329-349
    Contributions to Journals: Articles
  • Temporal stability of the rumen microbiota in beef cattle, and response to diet and supplements

    Snelling, T. J., Auffret, M. D., Duthie, C., Stewart, R. D., Watson, M., Dewhurst, R. J., Roehe, R., Walker, A. W.
    Animal Microbiome, vol. 1, no. 1, 16
    Contributions to Journals: Articles
  • Colitis susceptibility in mice with reactive oxygen species deficiency is mediated by mucus barrier and immune defense defects

    Aviello, G., Singh, A. K., O’Neill, S., Conroy, E., Gallagher, W., D’Agostino, G., Walker, A. W., Bourke, B., Scholz, D., Knaus, U. G.
    Mucosal Immunology, vol. 12, pp. 1316-1326
    Contributions to Journals: Articles
  • Compendium of 4,941 rumen metagenome-assembled genomes for rumen microbiome biology and enzyme discovery

    Stewart, R. D., Auffret, M. D., Warr, A., Walker, A. W., Roehe, R., Watson, M.
    Nature Biotechnology, vol. 37, pp. 953–961
    Contributions to Journals: Articles
  • Identification of Rumen Microbial Genes Involved in Pathways Linked to Appetite, Growth, and Feed Conversion Efficiency in Cattle

    Lima, J., Auffret, M. D., Stewart, R. D., Dewhurst, R. J., Duthie, C., Snelling, T. J., Walker, A. W., Freeman, T. C., Watson, M., Roehe, R.
    Frontiers in Genetics, vol. 10, 701
    Contributions to Journals: Articles
  • A Lot on Your Plate? Well-to-Well Contamination as an Additional Confounder in Microbiome Sequence Analyses

    Walker, A. W.
    mSystems, vol. 4, no. 4, e00362-19
    Contributions to Journals: Comments and Debates
  • Impact of carbohydrate substrate complexity on the diversity of the human colonic microbiota

    Chung, W. S. F., Walker, A. W., Vermeiren, J., Sheridan, P. O., Bosscher, D., Garcia-Campayo, V., Parkhill, J., Flint, H. J., Duncan, S. H.
    FEMS Microbiology Ecology, vol. 95, no. 1, fiy201
    Contributions to Journals: Articles
  • Studying the microbiome and its complexities: an interview with Alan Walker

    Walker, A. W.
    BMC Biology, vol. 16, no. 1, 134
    Contributions to Journals: Articles
  • Diet induced obesity is independent of metabolic endotoxemia and TLR4 signalling, but markedly increases hypothalamic expression of the acute phase protein, SerpinA3N

    Dalby, M. J., Aviello, G., Ross, A. W., Walker, A. W., Barrett, P., Morgan, P. J.
    Scientific Reports, vol. 8, 15648
    Contributions to Journals: Articles
  • Dietary fibers inhibit obesity in mice, but host responses in the cecum and liver appear unrelated to fiber-specific changes in cecal bacterial taxonomic composition

    Drew, J. E., Reichardt, N., Williams, L. M., Mayer, C., Walker, A. W., Farquharson, A. J., Kastora, S., Farquharson, F., Milligan, G., Morrison, D. J., Preston, T., Flint, H. J., Louis, P.
    Scientific Reports, vol. 8, 15566
    Contributions to Journals: Articles
  • The Impact of NOD2 Variants on Fecal Microbiota in Crohn’s Disease and Controls Without Gastrointestinal Disease

    Kennedy, N. A., Lamb, C. A., Berry, S. H., Walker, A. W., Mansfield, J., Parkes, M., Simpkins, R., Tremelling, M., Nutland, S., UK IBD Genetics Consortium, Parkhill, J., Probert, C., Hold, G. L., Lees, C. W.
    Inflammatory Bowel Diseases, vol. 24, no. 3, pp. 583-592
    Contributions to Journals: Articles
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