Denyce Wicht, PhD

Education

• PhD, Dartmouth College, Chemistry
• BA, University of Vermont, Chemistry (major), American Literature (minor)

Research Interests

Broadly speaking, my research interests involve understanding the mechanistic processes that cleave methyl group carbon bonds (–CH₃) to high-valent main group elements, specifically silicon (Si) and sulfur (S). I’m interested in silicon–carbon bonds (Si–CH₃) of the molecule dimethylsilanediol (abbreviated DMSD, structure shown below) because this specific molecule has been detected in environmental matrices. One source of DMSD in the environment is from chemical additives in personal care and other down-the-drain household products. Because no naturally occurring organosilicon compounds have been reported, chemical species containing silicon–carbon bonds, such as DMSD, are anthropogenic. The impacts of organosilicon xenobiotics are not entirely clear, but there is evidence for Si–CH₃ catabolism in mammals. The long-term goal of my research is the identification of a catalytic system that can efficiently break the Si–CH₃ bonds of DMSD under mild conditions and physiological pH. Neither a chemical nor a biological catalytic system has yet been identified. The identification of a catalyst capable of breaking a Si–CH₃ bond would be a significant advancement in the field and applicable to the design of systems engineered to treat environmental pollutants.

The other bond I’m interested in is the sulfur–carbon bond (S–CH₃ ) of the molecule dimethylsulfone (abbreviated DMSO₂, structure shown below). Unlike DMSD, DMSO₂ is a naturally occurring molecule. This compound enters the terrestrial environment through the chemical oxidation of biogenic dimethylsulfide, a compound that plays a major role in the global sulfur cycle. Despite the natural deposition of an estimated 2-8 million tons of DMSO₂ annually, DMSO₂ has not directly been detected in soil environments. In nature, it is speculated that soil bacteria biodegrade DMSO₂ . Perhaps indirect evidence for DMSO₂ deposition are reports of microorganisms isolated from soil that can utilize DMSO₂ for growth and metabolism, but the complete biochemical reactions that DMSO₂ undergoes have only recently been elucidated. An ongoing research interest of mine involves understanding the enzymatic pathways through which DMSO₂ is used by microorganisms. Understanding how soil bacteria break the sulfur–carbon bond (S–CH₃) in a naturally occurring molecule may provide insight into how to design a catalyst to break other methyl group carbon bonds (–CH₃) to high-valent main group elements.

Access the structures of dimethylsilanediol (DSMD) and dimethylsulfone (DMSO₂) [PDF].

Employment History

• Suffolk University
  Professor of Chemistry and Biochemistry, 2021-present
• Auburn University
  Visiting Scientist in the laboratory of Holly R. Ellis, Spring 2020 (on sabbatical)
• Massachusetts Institute of Technology
  Visiting Scientist in the laboratory of JoAnne Stubbe, 2013-2017 (summers)
• Massachusetts Institute of Technology
  Visiting Scientist in the laboratory of JoAnne Stubbe, 2012-2013 (on sabbatical)
• Suffolk University
  Associate Professor of Chemistry and Biochemistry, 2011-2021
  Assistant Professor of Chemistry and Biochemistry, 2005-2011
• Wellesley College
  Visiting Assistant Professor, 2003-2005
• General Electric Global Research Center
  Chemist; Polymer and Specialty Chemical Technologies, 2000-2002
• Massachusetts Institute of Technology
  Postdoctoral Associate, 1999-2000

Recent Publications

*denotes undergraduate co-author

Liew, J. J. M.; El Saudi*, I.; Nguyen, S. V*; Wicht, D. K.; Dowling, D. P.  Structures of the alkanesulfonate monooxygenase MsuD provide insight into C-S bond cleavage, substrate scope, and an unexpected role for the tetramer, J. Biol. Chem., 2021, 297(1), 100823.

Soule, J.; Gnann, A. D.; Gonzalez, R.; Parker, M. J.; McKenna, K. C.*; Nguyen, S. V*; Phan, N. T.*; Wicht, D. K.; Dowling, D. P. Structure and function of the two-component flavin-dependent methanesulfinate monooxygenase within bacterial sulfur assimilation, Biochem. Biophys. Res Commun. 2020, 522, 107-112.

Muirhead, D. L.; Wicht, D. K.; Stocker, K. M.; Perry, J. L.; Kayatin, M. J. A Simple Model to Estimate the Hydroxyl Radical Concentration and Associated DMSD Production Rates from Volatile Methyl Siloxanes in the ISS Atmosphere, 48th International Conference on Environmental Systems, Albuquerque, NM, July, 2018.

Wicht, D. K. The Reduced Flavin-Dependent Monooxygenase SfnG Converts Dimethylsulfone to Methanesulfinate. Arch. Biochem. Biophys. 2016, 604, 159-166.

O’Brien, K. E.*; Wicht, D. K. A greener organic chemistry experiment: Reduction of citronellal to citronellol using poly(methylhydro)siloxane. Green Chem. Lett. Rev. 2008, 1, 149-154.

Wicht, D. K. Green Chemistry Essay: We’re Going to Need a Bigger Earth. In Chemistry for Changing Times, 12th Edition; Hill, J. W.; McCreary, T. W.; Kolb, D. K.; Eds.; Pearson Prentice Hall: Upper Saddle River, NJ, 2010; p 336.

Wicht, D. K. Green Chemistry Essay: Catalysts. In Chemistry for Changing Times, 11th Edition, Hill, J. W.; Kolb, D. K.; Eds.; Pearson Prentice Hall: Upper Saddle River, NJ, 2007; p 320.

Wicht, D. K. Green Chemistry Essay: Antifouling in Rivers of Life; Seas of Sorrow. In Chemistry for Changing Times, 11th Edition; Hill, J. W., Kolb, D. K., Eds.; Pearson Prentice Hall: Upper Saddle River, NJ, 2007; p 378.

Oral Presentations

Concordia University Wisconsin, Mequon, WI, Oct., 2021

Wesleyan University, Middletown, CT, Oct., 2019.

255th Meeting of the American Chemical Society, New Orleans, LA, March, 2018.

University of Vermont, Burlington, VT, Nov., 2017.

Worcester Polytechnic Institute, Worcester, MA, Sept., 2015.

250th Meeting of the American Chemical Society, Boston, MA, Aug., 2015.

Bates College, Lewiston, ME, Jan., 2015.

Merrimack College, North Andover, MA, Oct., 2010.

Dartmouth College, Hanover, NH, May, 2010.

Hofstra University, Hempstead, NY, May, 2010.

12th Annual Green Chemistry and Engineering Conference, Washington D.C., June, 2008.

Worcester State University, Worcester, MA, March, 2008.

Grants & Awards

• $294,000: NSF Research at Undergraduate Institutions (RUI): Biophysical Characterization of Reduced Flavin-Dependent Two Component Monooxygenase Sulfur Assimilation Enzymes: SfnG, MsuC, and MsuD (2018-2021)
• $80,206: NASA, International Space Station Water Subsystem, Selective Removal of DMSO2 within the Water Processing Assembly/Oxygen Generation Assembly Water Loop by Enzymatic Processes (2019-2021)