Katie Pfeiffer.

Process Support Engineer, 2006 - 2008
Purification Development Engineer, 2005 - 2006
Pfizer Ltd
B.S. Chemical Engineering, 2005
Iowa State University

Office Location: 242 Energy Biosciences Building
Office Telephone: 510-666-2558

Quantifying and understanding lignin-cellulase interactions

Lignin makes up 20-30% of biomass dry weight, making it the second most abundant biomass component after cellulose. It remains present in biomass after all industrially-relevant pretreatment methods, and has been shown to inhibit biomass hydrolysis not only by physically blocking cellulase access to cellulose, but also by nonproductively binding cellulases and contributing to enzyme denaturation.

My work aims to quantify and engineer cellulase-lignin interactions through the application of quartz crystal microgravimetry (QCM). We isolate lignin representative of that found in dilute-acid pretreated biomass and use this lignin to create a lignin-coated QCM sensor. We track the real-time changes in surface mass as cellulase enzymes bind to the sensor under various conditions. This allows us to resolve not only equilibrium binding behavior, but also kinetics (on and off rates). We can also distinguish between reversible and irreversible binding. This is in contrast to previous batch-mode lignin binding experiments that produced equilibrium binding constants. This method for quantifying cellulase-lignin binding makes it possible to the study of effect of many factors that may affect lignin binding, including processing conditions, point mutations, and the enzyme domain contributions to lignin-cellulase binding.