Investigating the Thermostability of Lignocellulose-Degrading Enzymes

Background

The production of biofuels from the lignocellulosic wastes is severely hindered by the low efficiency of enzymatic conversion of lignocellulose to sugars.  These limitations can be overcome using thermostable enzymes because elevated temperature offers several potential advantages such as (i) improved hydrolysis of biomass, (ii) higher mass-transfer rates, and (iii) lowered risk of contamination.  We have isolated several thermophilic microbial strains having highly thermostable enzymes for lignocellulosic degradation. To the best of our knowledge, the endoxylanase is the most thermostable enzyme ever reported.  However, thermostable enzymes have only been subjected to biochemical characterizations.

Project Details

The student will use modeling software like LAMMPS to answer some key questions from previous work  (i) what will enhance the thermostability of enzymes, (ii) how do thermostable enzymes behave in high temperature micro-environment, and (iii) what is the thermodynamic feasibility of a given enzyme-ligand interaction at elevated temperatures?  Specifically, the student will model endoxylanase as a typical thermostable enzyme and study how the enzyme will respond to specific stress conditions like high temperature.  Tertiary structures of enzymes will then be subjected to molecular docking with a ligand to help decipher thermodynamic feasibility of a given enzyme-ligand interaction at elevated temperatures.  Also, the student will determine the effect of specific amino-acid substitutions within the enzyme to help answer the questions above and to understand adaptation of enzymes with high ligand activity.  These substitutions will then be replicated experimentally to produce desired mutations in wild-type endoxylanase using various molecular techniques.  A rendering of the enzyme can be seen below.

Skills Development

• Minor programming
• Molecular docking simulation techniques
• Molecular Dynamics
• Ligand docking mechanics
• Understanding of enzymatic activity and bioconversion

Research Duties

• Build and test simulations for thermophiles
• Quantify and observe thermostability
• Track ligand docking
• Perform amino acid substitution in model
• Compare results of different protein structures
• Provide insight to experimental work on how to improve thermophiles

Impact of Research

Studies of the activity of thermostable enzymes may in turn produce new engineering solutions to bio-fuels production which are more efficient and more economical.

Research Team

You will be working with both Dr. Sani and Dr. Hadley.

Dr. Sani has expertise in microbiology, biochemistry, and thermophiles.  He will serve as the project lead and guide the student on the specifics associated with how thermophiles behave and the structure of thermostable enzymes. 

Dr. Hadley has experience in modeling biological systems through molecular dynamic methods.  He will guide the student on the modeling aspects under the expertise of Dr. Sani.

For more details on this project, contact the lead investigator:

rajesh.sani@sdsmt.edu