Investigating the Thermostability of Lignocellulose-Degrading Enzymes

Enzymes are important in many industrial applications to control process times, extend shelf lives, reduce pollution, and decrease use of harmful chemicals. However, most enzymes are mesophilic, meaning they work best at moderate temperatures and denature at higher temperatures. Because there is this limit on process temperature, there is also a limit on the reaction rates. In contrast to mesophilic enzymes, thermostable enzymes work best at higher temperatures and offer several potential advantages: (i) the increased solubility of reactants and products, resulting in higher reaction velocities and decreases in the amount of enzyme needed; (ii) decreased mesophilic microbial risk of contamination, and thus, increased productivity; and (iii) decreased cost of energy. With these advantages, the goal of this research is to determine factors of thermostability and use this knowledge to enhance industrial enzymes, particularly xylanase, which is used in the production of biofuel. This poster will present results of molecular dynamics simulations used to determine which secondary structures are altered by increases in temperature. Results of heat increase in two model enzymes were used to compare structural changes: one thermostable (endo-beta-1,4-xylanase T6 from Geobacillus Stearothermophilus) and one mesophilic (endo-beta-1,4-xylanase from Streptomyces sp. s38). Comparison between the structures of enzymes with differing degrees of thermostability, factors that affect thermostability should become visible. With appropriate enzyme alterations, industries can have safer, more cost-effective and time-effective processes.