Dr. John Aston from Idaho National Laboratory to give Thermal Biology Seminar
- Monday, February 26, 2018 from 3:10pm to 4:00pm
- Plant BioScience Building room 108
Hemicellulose and cellulose represent a large renewable reservoir of sugars that could be converted into useful fuels and chemicals. Many pretreatment techniques have been developed that allow near complete conversion of hemicellulose and cellulose into their component sugars; however, the harsh conditions required by these techniques can cause the formation of harmful byproducts, including phenolic compounds that inhibit subsequent biologically-based conversions to fuels and chemicals. There is potential for the application of extremophilic hemicellulose- and cellulose-degrading enzymes to reduce the severity of pretreatments and reduce or eliminate these limitations. Of particular value would be heat and acid stable hemicellulase and cellulase enzymes. Numerous microorganisms from Yellowstone National Park were screened and various culture collections tested for the ability to produce these enzymes at both high temperatures and low pH. One organism tested, Alicyclobacillus acidocaldarius, produced both extracellular hemicellulase and cellulase activities. Our initial characterization studies determined that both the cellulases and hemicellulases were active from 20-90°C, with the cellulases active over pHs from 2-6 and the hemicellulases active from pH 1-5. Both the hemicellulase and cellulase activities were also found to be stable when incubated at 80°C and pHs ranging from 1-3.5. In addition, tests were performed to evaluate the resistance of A. acidocaldarius to industrially relevant inhibitors. A. acidocaldarius showed some resistance to phenolic and organic acid concentrations, and was able to remove such compounds from growth media.