Factors Affecting Soybean Crude Urease Extraction and Biocementation via Enzyme-Induced Carbonate Precipitation (EICP) for Soil Improvement

Enzyme-induced carbonate precipitation (EICP) is a new biogeotechnical ground improvement technique that uses calcium (CaCO3) formed by biochemical processes to increase soil strength and stiffness. In this paper, crude urease extracted from soybeans was employed catalyze the of CaCO3 in sand. To optimize extraction efficiency, factors affecting soybean extraction, including powdered particle size, concentration, soaking time, temperature, were addressed. This paper also provided further insight regarding impact activity extract on chemical conversion efficiency biocementation performance EICP. The findings revealed concentration size two most important extract. enzyme utilized EICP process might lead different reactant efficiencies urea-CaCl2 solution, consequently, physical mechanical properties biocemented Considering performance, 60 g/L concluded as preferred quantity for extracting urease, with an 6.62 mM urea min−1. Under condition, approximately 95% 0.5 M urea-0.5 CaCl2 could be obtained merely 12 h, unconfined compressive (UCS) EICP-treated sand exceeded 4 MPa content ~8%. As high-efficient cost-effective alternative purified precipitation, showed great potential improvement.