Undefined cellulase formulations hinder scientific reproducibility

Michael E. Himmel, Charles A. Abbas, John O. Baker, Edward A. Bayer, Yannick J. Bomble, Roman Brunecky, Xiaowen Chen, Claus Felby, Tina Jeoh, Rajeev Kumar, Barry V. McCleary, Brett I. Pletschke, Melvin P. Tucker, Charles E. Wyman, Stephen R. Decker

In the shadow of a burgeoning biomass-to-fuels industry, biological conversion of lignocellulose to fermentable sugars in a cost-effective manner is key to the success of second-generation and advanced biofuel production. For the effective comparison of one cellulase preparation to another, cellulase assays are typically carried out with one or more engineered cellulase formulations or natural exoproteomes of known performance serving as positive controls. When these formulations have unknown composition, as is the case with several widely used commercial products, it becomes impossible to compare or reproduce work done today to work done in the future, where, for example, such preparations may not be available. Therefore, being a critical tenet of science publishing, experimental reproducibility is endangered by the continued use of these undisclosed products. We propose the introduction of standard procedures and materials to produce specific and reproducible cellulase formulations. These formulations are to serve as yardsticks to measure improvements and performance of new cellulase formulations.