Dr Michelle Walker

Dr Michelle Walker
 Position University Research Fellow - B
 Org Unit School of Agriculture, Food and Wine
 Email michelle.walker@adelaide.edu.au
 Telephone +61 8 8313 0402
 Mobile +61 4 3492 3785
 Location Floor/Room 3 28 ,  Wine Innovation Central ,   Waite
  • Qualifications

    Bachelor of Science (Honours) in Agricultural Biochemistry, University College of Wales, Aberystwyth, Wales (1983)

    PhD in Microbiology, University of Edinburgh, Scotland (1988)

  • Research Interests

    Broad Research Interest: 

    Optimistion and characterisation of wine and brewer’s yeast (Saccharomyces cerevisiae)

    Specific Project Areas: 

    High throughput systems and functional genomics for identification of genes influencing yeast fermentation performance and wine composition

    Determination of the genetic basis for stress tolerance and fermentation attributes of wine yeast strains and their exploitation in strain improvement

    Use of non-recombinant approaches to generate wine and brewer’s yeast with improved fermentation capabilities

     

    For more information go to: http://www.agwine.adelaide.edu.au/winemicro/

     

  • Publications

    Peer review papers:

    Peter, J.J., Watson, T., Walker, M.E., Gardner, J.M., Lang, T.A., Borneman, A., Forgan, A., Tran, T. and V. Jiranek. (2018) Use of wine yeast deletion collection reveals genes that influence fermentation performance under low nitrogen conditions.  FEMS Yeast Research. Feb 7. doi: 10.1093/femsyr/foy009.

    Zhang, J., Astorga, M.A., Gardner, J.M., Walker, M.E., Grbin, P.R., Jiranek, V. (2018) Disruption of the cell wall integrity gene ECM33 results in improved fermentation by wine yeast. Metabolic Engineering 45, 255-264.

    Nguyen, T. D., Walker, M. E., Gardner, J.M., and Jiranek, V. (2017) Appropriate vacuolar acidification in Saccharomyces cerevisiae is required for efficient high sugar fermentation. Food Microbiology 70, 262-268: https://doi.org/10.1016/j.fm.2017.09.021

    Huang, C-W., Walker, M., Fedrizzi, B., Roncoroni, M., Gardner, R. and Jiranek, V. (2017) Hydrogen sulfide and its roles in Saccharomyces cerevisiae in a winemaking context.  FEMS Yeast Res.  17(6): doi: 10.1093/femsyr/fox058.

    Huang, C-W., Walker, M., Fedrizzi, B., Roncoroni, M., Gardner, R. and Jiranek, V. (2017) Yeast genes involved in regulating cysteine uptake affect production of hydrogen sulfide from cysteine during fermentation. Submitted date: 27-Mar-2017 Accepted date: 27-Jun-2017 FEMSYR-17-03-0047.R1

    Huang, C-W., Walker, M., Fedrizzi, B., Roncoroni, M., Gardner, R. and Jiranek, V. (2016) The yeast TUM1 affects production of hydrogen sulfide from cysteine treatment during fermentation. FEMS Yeast Res. 16 (8): fow100. doi: 10.1093/femsyr/fow100

    Walker, M. E., Nguyen, T. D., Liccioli, T., Schmid, F., Kalatzis, N., Sundstrom, J. F., Gardner, J. M., and Jiranek, V. (2014) Genome-wide identification of the fermentome; genes required for successful and timely completion of fermentation by Saccharomyces cerevisiae. BMC Genomics 15:552  doi:10.1186/1471-2164-15-552 Published: 3 July 2014 http://www.biomedcentral.com/1471-2164/15/552 

    Capaldo, A., Walker, M.E., Ford, C.F., and V. Jiranek (2011) beta-Glucoside metabolism in Oenococcus oeni: Cloning and characterisation of the phospho-beta-glucosidase bgID. Food Chemistry, 125(2):476-482

    Liccioli, T., Walker, M.E., Sundstrom, J.F., Gardner, J.M., and Jiranek, V. (2013)
    Novel wine yeast for improved  performance in fermentationWine & Viticulture Journal  28 (6): 30-33

    Capaldo, A., Walker, M.E., Ford, C.F., and V. Jiranek (2011) β-Glucoside metabolism in Oenococcus oeni: cloning and characterization of the phospho-β-glucosidase CelD. Journal Molecular of Catalysis B: Enzymatic, 69(1-2):27-34

    Poole, K.A., Walker, M.E., Warren, T., Gardner, J. M., McBryde, C.M., de Barros Lopes, M., and  V. Jiranek (2009) Proline transport and stress tolerance of ammonia-insensitive mutants of the PUT4-encoded proline-specific permease in yeast. Journal of General and Applied Microbiology, 55(6):427-439

    Astorga, A.M., Gardner, J.M., McBryde, C., Schmid, F., Walker, M.E., and V. Jiranek (2007) Optimisation of industrial strains of Saccharomyces cerevisiae using recombinant and non-recombinant methods. Microbiol. Aust.25 62-63

    Walker, M.E., Vystavelova, A., Pedler, S., Eglington, J. and V. Jiranek (2005) PCR-based gene disruption and recombinatory marker excision to produce modified industrial Saccharomyces cerevisiae without added sequences. J. Microbiol. Methods 63 193-204

    Matthews, A., Grimaldi, A., Walker, M.E., Bartowsky, E., Grbin, P. and V. Jiranek (2004) Lactic Acid Bacteria as a Potential Source of Enzymes for Use in Vinification. Appl. Environ. Microbiol. 70(10) 5715-5731

    Walker, M.E., Gardner, J.M., Vystavelova, A., McBryde, C., des Barros Lopes, M. and V. Jiranek (2003) Application of the reuseable, KanMX selectable marker to industrial yeast: construction and evaluation of heterothallic wine strains of Saccharomyces cerevisiae, possessing minimal foreign DNA sequences. FEMS Yeast Research 4(3) 339-347

    Walker, M.E., Gardner, J.M., des Barros Lopes, M. and V. Jiranek (2002)Wine yeasts as tools for oenological research and strain improvement by genetic techniques. The Australian & New Zealand Grapegrower & Winemaker, Annual Technical Issue. 406a 109-115

    Jitrapakdee, S., Walker, M.E. and J.C. Wallace (1999) Functional Expression, Purification, and Characterization of Recombinant Human Pyruvate CarboxylaseBiochem. Biophys. Res. Commun. 266 512-517

    Jitrapakdee, S., Walker, M.E. and J.C. Wallace (1996) Identification of Novel Alternatively Spliced Pyruvate Carboxylase mRNAs with Divergent 5' -Untranslated Regions Which Are Expressed in a Tissue-Specific Manner.Biochem. Biophys. Res. Commun. 223 695-700

    Val, D.L., Chapman-Smith, A., Walker, M.E., Cronan, J.E., and J.C. Wallace (1995) Polymorphism of the yeast pyruvate carboxylase 2 gene and protein: Effects on biotinylation. Biochem. J. 312 817-825

    Walker, M.E., Baker, E., Wallace, J.C.. & G.R. Sutherland (1995)Assignment of the human pyruvate carboxylase gene (PC) to 11q13.4 by fluorescence in situ hybridisation. Cytogenetics and Cell Genetics 69 187-189

    Brewster, N.K., Val, D.L., Walker, M.E. & J.C. Wallace (1994) Regulation of pyruvate carboxylase isoenzyme (PYC1PYC2) gene expression inSaccharomyces cerevisiae during fermentative and non-fermentative growth.Arch. Biochem. Biophys. 311(1) 62-71

    Walker, M.E., Val, D.L., Rohde, M., Devenish, R.J. & J.C. Wallace (1991) Yeast pyruvate  carboxylase: Identification of two genes encoding isoenzymes.  Biochem. BiophysRes. Commun. 176 (3) 1210-1217

    Walker, M.E. & J.C. Wallace (1991) Isolation of a yeast mutant deficient in pyruvate carboxylase activity. Biochem. Int23(4) 697-705

     

    Industry Articles:

    Walker, M.E., Gardner, J.M., des Barros Lopes, M. and V. Jiranek (2002) Wine yeast as tools for oenological research and strains improvement by genetic techniques.  The Australian & New Zealand Grapegrower & Winemaker, Annual Technical Issue.  461a 109-114

    Walker, M.E., Sundstrom, J.F., Liccioli, T., Dillon, S., Long, D., Nguyen, T., Tek, E-L. and J. Zhang (2014)  Adelaide researchers head ‘over the ditch’ for Australisian yeast meeting. Grapegrower and Winemaker March 2014 - Issue 603. www.winebiz.com.au 

    Walker, M.E., Gardner, J., Liccioli, T. and V. Jiranek (2014) Tackling microbial failure in problematic wine fermentations using a holistic approach.  Grapegrower and Winemaker April 2014 - Issue 604.  www.winebiz.com.au

     

    Liccioli, T., Walker, M.E., Sundstrom, J.F., Gardner, J.M. and V. Jiranek (2013) Novel wine yeast for improved performance in fermentation. Wine and Viticulture J. http://winetitles.com.au/wvj/

     

    Conference Abstracts (since 2000)

    (Presenting Author in bold) 

    2001  11th Australian Wine Industry Technical Conference (Adelaide)

    Poster: “Construction and evaluation of haploid wine yeast for research purposes” M.E. Walker, Gardner, J.M., and V. Jiranek

    2002  2nd Australian Conference on Yeast: Products and Discovery (Melbourne)

    Poster:”Development of Heterothallic Wine Yeast Strains for Oenological Research” M.E. Walker, Gardner, J, Vystavelova, A., and V. Jiranek

    2004  12th Australian Wine Industry Technical Conference (Melbourne)

    Walker, M., Vystavelova, A., Pedler, S., Eglinton, J., and Jiranek, V. (2004) Towards tools for ‘seamless’ modification of genes in industrial yeast. Proc. 12th Aust. Wine Ind. Tech. Conf. July, 2004, Melbourne. p 290.

    2007  23rd International Conference on Yeast Genetics and Molecular Biology (Melbourne)

    Poster: “Screening of transposon mutation libraries in a wine yeast background to identify genes contributing to successful fermentation” M.A. Astorga., Gardner, J.M., Walker, M.E., de Barros Lopes, M., andV. Jiranek

    2007  23rd International Conference on Yeast Genetics and Molecular Biology (Melbourne)

    Poster: “Strategies for the Generation of Wine Yeast Strains with Novel Fermentation Traits” M.E. Walker, Gardner, J.M., McBryde, C., Schmid, F., Macintyre, A., Bishop, A., and V. Jiranek

    2007  23rd International Conference on Yeast Genetics and Molecular Biology (Melbourne)

    Poster: “An automated fermentation system for evaluation of large numbers of yeast strains in laboratory wine fermentations” F. Schmid,Walker, M.E., and V., Jiranek

    2007 23rd International Conference on Yeast Genetics and Molecular Biology (Melbourne)

    Poster: “Screening of a mutagenic transposon library in a wine yeast background to identify genes contributing to successful fermentation”J.M. Gardner, A.M. Astorga, M.E. Walker and V. Jiranek

    2007 13th Australian Wine Industries Technical Conference (Adelaide)

    Poster: Strategies for the Generation of Wine Yeast Strains with Novel Fermentation Traits” M.E. Walker, Gardner, J.M., McBryde, C., Schmid, F., Macintyre, A., Bishop, A., and V. Jiranek

    2007  13th Australian Wine Industries Technical Conference (Adelaide)

    Poster: “Construction and of wine yeast with increased tolerance to osmotic stress and their evaluation under wine fermentation” N. Lam, Walker, M. E., and V. Jiranek

    2007  13th Australian Wine Industries Technical Conference (Adelaide)

    Poster: “An automated fermentation system for evaluation of large numbers of yeast strains in laboratory wine fermentations” F. Schmid,Walker, M.E., and V., Jiranek

    2007  13th Australian Wine Industries Technical Conference (Adelaide)

    Poster:  “Expression and characterisation of a β-glucosidase gene from Oenococcus oeni for oenological use” A. Capaldo, M.E. Walker, C. Ford and V. Jiranek,

    2009  24th International Conference on Yeast Genetics and Molecular Biology (Manchester)

    Poster:  “The influence of wine yeast on colour extraction and stabilisation in red wine” M.E. Walker, Liccioli, T., Warren, T., Capaldo, A., Schmid, F., and V. Jiranek

    2009  24th International Conference on Yeast Genetics and Molecular Biology (Manchester)

    Poster: “Adaptive evolution strategies for the generation of novel wine yeast”

    McBryde,  C., Gardner, J.M.,  Walker, M.E., and V. Jiranek

    2009  24th International Conference on Yeast Genetics and Molecular Biology (Manchester)

    Poster: “Enzymatic activities of Lactic Acid Bacteria: Distribution, cloning and characterisation of esterases and glycosidases” K. Sumby, Capaldo, A., Walker, M.E., Grbin, P., Ford, C. and V. Jiranek

    2009  4th Australian conference on Yeast: Products and Discovery (Adelaide)

    Talk: “Progress towards improvement of industrial yeast for the wine industry” M.E. WalkerGardner, J.M., Liccioli, T., Schmid, F., McBryde, C., and V. Jiranek

    2009  4th Australian conference on Yeast: Products and Discovery (Adelaide)

    Poster: “Progress towards characterisation of an adaptively evolved wine yeast strain” J.M. Gardner, McBryde, C.,  Walker, M.  and V Jiranek

    2010  14th Australian Wine Industries Technical Conference (Adelaide)

    Poster: “The identification of genes with the potential to influence wine colour and fermentation duration.” M. E. Walker, Liccioli, T., Schmid, F., Kalatzis, N., Gardner, J.M., Grbin, P.R. and V. Jiranek

    2011   Crush 2011 (Adelaide)

    Talk: “Identification and classification of Saccharomyces cerevisiaegenes required for high-sugar fermentation using a genome-wide screening approach” M.E. Walker, Liccioli, T., Schmid, F., Trung, D.N., Kalatzis, N., Sundstrom, J., Gardner, J.M., and V. Jiranek

    2011   School of Agriculture Food & Wine Research Day, University of Adelaide

    Talk: “Investigation of the genetic basis of high nitrogen efficiency (HNE) in wine yeast” J. Zhang, Gardner, J.M., Walker, M.E., Sundstrom, J.F., Grbin, P. and V. Jiranek 

    2012   Crush 2012 (Adelaide)

    Talk: “Investigation of the genetic basis of high nitrogen efficiency (HNE) in wine yeast” J. Zhang, Gardner, J.M., Walker, M.E. and V. Jiranek 

    2013   15th Australian Wine Industries Technical Conference (Sydney)

    Poster: “Second generation yeast with reduced hydrogen sulfide and sulfur dioxide

    production” M.E. Walker, Lee, A., Houlés, A., Adint, L., Li, S. and V. Jiranek

    2013   15th Australian Wine Industries Technical Conference (Sydney)

    Poster: “Genome screening as an approach to understand the cellular mechanisms behind yeast adaptation during fermentation to allow for successful completion”

    M. E. Walker, Liccioli, T., Schmid, F., Gardner, J. M., Kalatzis, N., Grbin, P. R. and V. Jiranek

    2013   15th Australian Wine Industries Technical Conference (Sydney)

    Poster: “Vacuolar acidification may play a key role in the ability of yeast to successfully complete industrial fermentation”

    T. D. Nguyen, Walker, M. E., Gardner, J. M., and V. Jiranek

    2013   15th Australian Wine Industries Technical Conference (Sydney)

    Poster: “Re-starting stuck wine fermentations using an evolved wine yeast. T.   Liccioli, Gardner, J., Walker, M., Sundstrom, J., Shearer, M. and V. Jiranek

    2013   15th Australian Wine Industries Technical Conference (Sydney)

    Poster: “Investigation of the genetic basis of high nitrogen efficiency (HNE) in wine yeast” J. Zhang, Gardner, J.M., Walker, M.E., Astorga, M.A., Sunstrom, J.,  Grbin, P. and V. Jiranek 

    2013   Australasian conference on Yeast: Products and Discovery (Auckland)

    Talk: Overexpression studies – an approach to understand the mechanisms behind successful alcoholic fermentation. M. Walker, Haggerty, J., Zhang, J., Nguyen, T. D., Sundstrom, J. Liccioli, T., Gardner, J. and V. Jiranek

    2013   Australasian conference on Yeast: Products and Discovery (Auckland)

    Talk: “Genome wide screening for the identification of genes influencing colour in red wine fermentations” T. Liccioli, Walker, M., Schmid, F., Kalatzis, N., Gardner, J., Grbin, P. and V. Jiranek.

    2013   Australasian conference on Yeast: Products and Discovery (Auckland)

    Talk: “Investigation and characterization of an High Nitrogen Efficient (HNE) wine yeast strain” J. Zhang, Gardner, J. M., Walker, M. E., Astorga, M. A., Grbin, P. and V. Jiranek.

    2013   Australasian conference on Yeast: Products and Discovery (Auckland)

    Poster: “Evaluation of fermentation efficiency of yeast Saccharomyces cerevisiae tps1 and tps2 deletants with over-expression of HXK2and TreA genes.” T. D. Nguyen, Walker, M. E., Gardner, J. M. and V. Jiranek

    2015   Oeno 2015: 10th International Symposium of Oenology of Bordeaux, (Bordeaux, France)

    Talk: “Generation and characterisation of improved wine microbes.”. Jiranek, V., Liccioli, T., Betteridge, A., Sumby, K., Walker, M., Gardner, J., Sundstrom, J.

    2015    Australasian conference on Yeast: Products and Discovery (Adelaide)

    Talk: “The impact of brief temperature shifts on wine fermentation.” Valentine, G.D.S., Walker, M., Gardner, J., Schmid, F. and V. Jiranek

    2015    Australasian conference on Yeast: Products and Discovery (Adelaide)

    Talk: “Screening for wine yeast mutants, whereby gene deletion results in faster fermentation under limited nitrogen conditions.” Peter, J.J., Watson, T., Walker, M., Gardner, J. and V. Jiranek

    2015    Australasian conference on Yeast: Products and Discovery (Adelaide)

    Talk: “Identification of yeast genes responsible for the production of hydrogen sulfide and volatile thiols in wine.” Huang, M, Gardner, R., Fedrizzi, B., Walker, M. and V. Jiranek

    2015   Australasian conference on Yeast: Products and Discovery (Adelaide)

    Talk: “Can further improvements be made in oenological traits of wine yeast?” Walker, M.E., Watson, T., Long, D., Lang, T., Zhang, J., Gardner, J.M. and V. Jiranek

    2015    Australasian conference on Yeast: Products and Discovery (Adelaide)

    Talk: “Screening for wine yeast mutants, whereby gene deletion results in faster fermentation under limited nitrogen conditions”

    Peter, J.J., Watson, T., Walker, M., Gardner, J. and V. Jiranek

    2015    Australasian conference on Yeast: Products and Discovery (Adelaide)

    Talk: “The impact of brief temperature shifts on wine fermentation”

    Valentine, G.D.S., Walker, M., Gardner, J., Schmid, F. and V. Jiranek

    2015   2015   Crush 2015 (Adelaide)

    Talk: Mapping of genes responsible for yeast-derived modulation of colour in model red wine

    Walker M., Watson, T., Roncoroni, M., Gardner, R. and V. Jiranek

    2016   14th International Congress on Yeasts (Awaji Island, Japan)

    Talk and Poster: “Identification of yeast genes responsible for the production of hydrogen sulfide (from cysteine) and volatile thiols in wine”

    Huang, M., Gardner, R., Fedrizzi, B., Walker, M. and V. Jiranek

    2016   14th International Congress on Yeasts (Awaji Island, Japan)

    Talk and Poster: “Mapping of genes responsible for yeast-derived modulation of colour in model red wine”

    Walker, M., Watson, T., Roncoroni, M, Gardner, R and V. Jiranek

     

     

      

     

  • Professional Associations

    Member of Australian Society of Biochemistry and Molecular Biology

    Member of The Australasian Yeast Group

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Entry last updated: Thursday, 24 May 2018

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