The Hallam Lab

Investigating microbial communities…

GSAT Rotation Students

To probe the genetic potential and function that exists within an environment, metagenomic libraries are created from environmental DNA and are typically hosted in E. coli. Because these libraries may contain upwards of 100,000 unique clones, our focus is on the development of high-throughput methodologies to enable us to examine these libraries in a methodical and automated manner. Our lab integrates in silico genetic probing with in vitro discovery methods for the identification of enzymatic functions of interest. Currently our primary interests are in the degradation of organic matter, including cellulose, hemicellulose, and lignin. Most of our GSAT rotation students work on a project in functional metagenomics, though we also have a large bioinformatic team for those students who may be more computationally inclined.

High Throughput Functional Screening for Cellulase Activity
Keith Mewis, Spring 2010

Cellulose is a primary component of plant cell walls and is the planet’s largest source of organic carbon. Current efforts to use cellulosic biomass as a feedstock for biofuel production are hampered by the high cost and relatively low activity of current enzymes. The discovery of robust, novel, and mass producible enzymes may have immediate impact to global industry.

In this rotation project, I developed a high throughput screening methodology to detect cellulase activity against a cellulose model compound. The screen involved automation and robotics for liquid dispensing and plate handling and is currently capable of screening >100,000 individual E. coli clones. The modularity of the screen allows it to be applied for the detection of any activity for which a fluorogenic or colorimetric substrate can be designed and synthesized. This work was published in the Journal of Visualized Experimentation (JoVE).

Our current efforts in this project are towards the discovery of lignin modifying enzymes, and the use of alternate hosts such as yeast for functional screening.