Assessing pH Conditions on Urease Enzyme Activity

Anna Martinson, Arda Akyel, Dr. Robin Gerlach,and Dr. Adrienne Phillips College of Engineering Montana State University Bozeman 237 Norm Asbjornson Hall, Bozeman, MT 59717, United States

Urease Induced Calcium Carbonate Precipitation (UICP) has been shown to seal sub-surface fractures by catalyzing hydrolysis of urea to promote mineral precipitation. The applications for UICP could be useful in carbon capture and storage (CCS) to fix or prevent leaks at the sites. CCS sites tend to have low pH due to supercritical CO2 and water mixing. The purpose of this study is to investigate urease’s ability to withstand exposure to pH conditions less than 6 and at temperatures as high as 60˚C to broaden the applications UICP could be used in because enzyme activity may be inhibited by low pH or high temperature conditions. To study urease kinetics after exposure to low pH and high temperature conditions jack bean meal (JBM) urease was prepared two ways, a suspended mixture and immobilized on a ceramic proppant. These were exposed to pH conditions between 3.7 and 7 at 22˚C and 60˚C. After exposure to low pH for 1 hour, the pH was increased to 7 and a batch kinetic study was run for 48 hours at 22˚C to measure the ureolytic activity. Suspended JBM urease remained active after exposure to the condition of pH 4.2 at 22˚C and immobilized urease remained active after all pH exposures, though slower at pH 3.7. When exposed to low pH and 60˚C, the suspended JBM showed ureolytic activity after exposure to 4.7 and the immobilized JBM had minimal ureolytic activity after exposure to pH 4.1. This suggests that UICP could be used in CCS applications. 

Additional Abstract Information

Presenter: Anna Martinson

Institution: Montana State University Bozeman

Type: Oral

Subject: Biological & Chemical Engineering

Status: Approved

Time and Location

Session: Oral 3
Date/Time: Mon 4:30pm-5:30pm
Session Number: 304
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