MICP ADDITIVE DEPOSITION RESEARCH
One of the component systems I want to work on is a multi material nozzle for bio-printing. Specifically for Microbial-Induced Calcite Precipitation (MICP).
MICP uses naturally occurring bacteria to bind soil particles together through calcium carbonate (CaCO3) crystals. The bacteria most commonly used is Sporosarcina Pasteurri (S.Pasteurri). To activate the process the bacteria are combined with a cementation solution of Urea and Calcium. Urea is a crystalline compound that is the main nitrogenous breakdown product of protein metabolisms. Urea is used as a fertilizer as well as a starting material for the manufacture of plastics and drugs. The process of MICP through bacteria, urea, and calcium ions is known as microbial urea hydrolysis.
Parameters involved in MICP:
-ration of bacteria, urea, and calcium
-even and thorough flush of cementation solution (urea and calcium) on bacteria
-pH level of cementation solution around 6-7 (will increase to about 9 with bacterial activity)
-access to oxygen
-optimal temperature (growing at 30C(86F)
Typical problems with MICP
-insufficient amount of chemicals into soil volume
-oxygenation for the bacteria
Current MICP applications rely on creating molds or using binder jetting techniques. I am interested in developing an alternative, Liquid Deposition
Modeling (LDM) approach in order to scale up the use of MICP to earthen shelters.
3D bio-print, Dosier
MICP Brick, Dosier
MICP Binder Jetting Printer, Nething et al.
Biocemented Sand, Gerlach
Another investigation this week was about the sourcing of the S. Pasteurii bacteria and the cultivation process. Following recommendations from the
How To Grow class TAs it seems that the American Type Culture Collection (ATCC) is a reliable source to use. The website had really helpful
recommendations for storage and propagation techniques as well as safety guidelines. The bacteria is a biosafety level 1 meaning the substance is
not hazardous but should be handled with good lab practices and proper personal protective equipment. For the full documentation click
HERE.References:
“Sporosarcina Pasteurii (Miquel) Yoon Et Al. (ATCC® 11859™).” Sporosarcina Pasteurii (Miquel) Yoon Et Al. ATCC ® 11859™, www.atcc.org/products/all/11859.aspx#generalinformation.
Bhaduri, Swayamdipta, et al. “Microbiologically Induced Calcite Precipitation Mediated by Sporosarcina Pasteurii: Protocol.” JoVE (Journal of Visualized Experiments), 16 Apr. 2016, www.jove.com/v/53253/microbiologically-induced-calcite-precipitation-mediated-sporosarcina.
Nething, Christoph, et al. “A Method for 3D Printing Bio-Cemented Spatial Structures Using Sand and Urease Active Calcium Carbonate Powder.” Materials & Design, vol. 195, 2020, p. 109032., doi:10.1016/j.matdes.2020.109032.
Week of 03/08