Leadership and Professional Staff

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Thomas W. JeffriesPresident and Founder

Dr. Jeffries has forty years of leadership experience in microbial biochemistry, physiology and metabolic engineering of yeasts. He began working full time to build Xylome in January of 2013. Dr. Jeffries’ professional experience roles as Scientist, Senior Scientist and former Director of the Institute for Microbial and Biochemical Technology at the USDA Forest Products Laboratory in Madison, Wisconsin. As a USDA Professor, he taught Biotechnology and Industrial Microbiology at the University of Wisconsin-Madison. Dr. Jeffries provides strategic direction to the scientific team by selecting yeast platforms, commercial targets and metabolic approaches, and he conducts process and strain development.

His areas of expertise include :

  • Thermochemical and biochemical pretreatments for the bioconversion of cellulosic and hemicellulosic materials to fuels and chemicals,
  • Physiology and metabolic regulation of yeasts and fungi, genetics and biochemistry of yeasts,
  • fermentation, yeast metabolic engineering, development of yeast genetic transformation technologies, large scale expression analysis, and yeast genomics.

Thomas J. KelleherChief Executive Officer

Dr.Thomas Kelleher is a biotechnologist with more than 30 years of leadership experience in the industrial production of recombinant biopharmaceuticals, antibiotics and industrial enzymes. He has worked for and with consulting engineering firms to complete the realization of seven commercial production facilities.

He most recently was a director of Process Development at Amgen during the 12-year expansion of commercial sales from $9 to $20 billion/yr.  Prior to joining Amgen, Dr. Kelleher was the Senior Director of Manufacturing and Process Development at Cubist where he led manufacturing, process development, plant construction and long-term contractual supply agreements for the FDA Licensing of Cubicin, an antibiotic of last-resort for Vancomycin Resistant Enterococcus (VRE) and MRSA “super bugs”. Cubicin was the first new-class of antibiotic in 32 years. It has now served 2 million patients and has licensed sales that exceeded $1 billion dollars in 2012.

Prior to these leadership assignments, Dr. Kelleher held positions of increasing responsibility at Biowork-IMS Inc., ZymoGenetics/Novo Nordisk, Chiron/Cooper Laboratories and Millipore/Worthington Biochemicals.  Kelleher’s Ph.D. thesis was on lignocellulosic biochemistry in fungi.

His areas of expertise include :

  • Production of recombinant biopharmaceuticals, antibiotics and industrial enzymes
  • Industrial consultation for process development
  • GMP production of injectables and biologicals

Professional Staff

David Z. MokryMetabolic Engineering

Dr. David Z. Mokry is a biochemist and molecular biologist with more than 10 years of professional experience. In addition to expertise in metabolic engineering, genetic manipulation, and high-throughput screening in non-traditional yeast, he has extensive experience in protein characterization by biochemical, biophysical, and biological techniques. Dr. Mokry has published in several research areas, including yeast complementation, protein folding, and membrane protein biology.

Christopher H. CalveyMetabolic Engineering

Dr. Chris Calvey is a cellular and molecular biologist with more than seven years of experience in molecular and synthetic biology with particular emphasis on yeast metabolic engineering and in vitro enzymatic DNA assembly techniques, which he used while part of the team that created the world’s first synthetic bacterial cell. Dr. Calvey was the first to develop a genetic transformation system for the oleaginous yeast Lipomyces starkeyi, and he has established optimal conditions for lipid synthesis in this organism.

Phillip R. DisherDirector of Marketing

Phillip Disher, MBA, is an innovative voice in the world of marketing whose creativity, unique experience and knowledge has contributed to the successful strategic development, management and execution of various national and international brand campaigns. His diverse, cross-industry experience includes high-profile projects with several of the world’s most recognized brands such as Dow Chemical, United Nations Foundation, Coca-Cola, and FIFA. He holds a MBA with a concentration in Business Analysis from Georgia State University and a Bachelor of Science in Business Administration from the University of North Carolina at Chapel Hill.

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