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Expert Witness Services



Xylome provides expert witness services and consulting for:

  • Patent litigation
  • Fact finding
  • Expert discovery
  • Bioprocess engineering
  • Metabolic engineering
  • Biopharmaceutical processes
  • Microbiological fermentation processes

Xylome’s expert witnesses are highly knowledgeable, experienced and skilled

Dr. Thomas Kelleher, Ph.D.

Dr. Kelleher has accumulated more than 35 years of practical experience in the biopharmaceutical industry.  In the process he has served as a microbiology expert in numerous patent litigations for biopharmaceutical processes, due diligence, product inspections and litigations.

Kelleher is well recognized as an expert witness U.S. and Europe involving branded drug companies, corporations and individuals. In this time Dr. Kelleher has supported his clients during fact finding, expert discovery, laboratory notebook reviews and claim analysis.  In addition he has provided general biopharmaceutical process and microbiology consultations, patent reviews, expert opinions, depositions and trial testimonies.

He has achieved significant leadership positions in

  • Good Manufacturing Practice (GMP) process development
  • Bio-Pharmaceutical facility design, and technical services.
  • Compliance inspections at major biopharmaceutical companies including Cubist, Novo Nordisk and Amgen.

Dr. Kelleher’s industrial expertise, and expert witness experience are as follow:

  • Product purity and review of manufacturing deviations
  • Intellectual property discovery and due diligence
  • Pharmaceutical microbiology, Contamination control and aseptic design reviews
  • Sterilization and aseptic process validation, Good Manufacturing Practices (GMPs)
  • Inspection Readiness, Bio-Pharmaceutical manufacturing operations
  • Technical Services and analytical laboratory operations and validation study reviews

Dr. Kelleher has provided court testimony, key documents and/or dispositions on multiple occasions:

  • Hospira UK Limited and Cubist Pharmaceuticals, LLC
  • Hospice, Inc., Defendant-Appellant Appeals from the United States District Court for the District of Delaware
  • Fresenius vs Cubist, settled post deposition
  • Cubist vs Hospira Court Testimony
  • Notice to Take Deposition

Dr. Kelleher has consulted on biotech facility design and provided owner representation during biotechnology construction programs.   Additional expert witness and due diligence cases may be pending. Please contact Dr. Kelleher to discuss his fees and availability as a microbiology expert witness. 805-603-9736, tkelelher@xylome.com

Click here to view Dr. Kelleher’s Linkedin CV

Reference: Robert Galvin Esq. Wilmer Hale, 950 Page Mill Rd, Palo Alto CA 94304, robert.galvin@wilmerhale.com


Thomas W. Jeffries, Ph.D., Prof. Emeritus

Dr. Jeffries has accumulated more than 35 years of experience as a Senior Scientist in the USDA and as a Professor at the University of Wisconsin-Madison. He is a recognized expert in microbial physiology, biochemistry and metabolic engineering of yeasts. Jeffries has published more than 165 peer reviewed papers and reviews.

He gained significant experience as an expert witness in patent litigation for industrial process and products. He has served as a consultant for industrial yeast processes, as an advisor in due diligence and in troubleshooting plant operations.

Jeffries has served as an expert witness for U.S. and European companies involving yeast-based processes and the genetics of industrial microorganisms.

Dr. Jeffries is an expert in the following areas:

  • Yeast process patents involving yeast genetics and metabolic engineering
  • Intellectual property due diligences and expert reports
  • Analysis of novel industrial, microbiological, biochemical and metabolic engineering processes and patents
  • Disposition experience and a deep understanding of current scientific literature and methodologies
  • Large-scale industrial process trouble-shooting and process reviews

Click here to view Dr. Jeffries’ Linkedin CV

Reference: Joseph Mahoney Esq., Jonathan H. Kim, PhD: Mayer Brown, 71 S. Wacker St. Chicago, IL 60606, jamahoney@mayerbrown.com

Please contact Dr. Jeffries to discuss his fees and availability as a microbiology expert witness. 608-698-4470, twjeffries@xylome.com


Dr. David Z.  Mokry, Ph.D. and Dr. Christopher Calvey, Ph.D.

Dr’s Mokry and Calvey are highly skilled molecular biologists and metabolic engineers who are available for consultation on technical aspects of gene construction, transformation, expression, and genetics of both conventional and non-conventional yeast.

Click here to view Dr. Mokry’s Linkedin CV

Click here to view Dr. Calvey’s Linkedin CV