Name: microbiologically induced calcite precipitation mediated by sporosarcina pasteurii
Uploaded: 2016-04-16T14:00:00
Description: Watch this Scientific Journal Video about Microbiologically Induced Calcite Precipitation Mediated by Sporosarcina pasteurii at JoVE.com

We wish to acknowledge the partners in the Helmholtz-Alberta Initiative, the Helmholtz Association and the University of Alberta, for the support resulting from participation in this collaboration. Research funding is provided by the Helmholtz Association's Initiative and Networking Fund, the participating Helmholtz Centers and by the Government of Alberta through Alberta Environment's ecoTrust program.
Dr. Tanushree Ghosh is gratefully acknowledged for her critical inputs at a number of crucial stages.

NOTE: Perform the experimental protocols in the order described below. The bacterial culture protocol is discussed in Section 1 (Also see Figure 1). Section 2 describes the protocol for enriching the culture medium using external additives. Section 3 describes the protocols for multi-mode microscopy. Weights of all the individual components may be measured using an analytical balance. Volume of each solution may be measured using a volumetric cylinder.
NOTE: Proper biosafety p...

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Critical Steps: This manuscript describes in detail the protocols for culturing a viable sample of S. pasteurii. Once the culture has been readied, it must be suitably enriched. This is a key step vital to the success of the experiment because a failure to provide the proper chemical environment leads to either very long time scales of precipitation or a complete lack thereof. S. pasteurii is quite sensitive to several external agencies and must be cultured with a high degree of care an...

Sporosarcina pasteurii is a gram-positive bacterium able to survive in highly alkaline environments (pH~10)1 and is one of the bacterial species that can become a causative agent of a phenomenon called Microbiologically Induced Calcite Precipitation (MICP)2-4. MICP is a process wherein precipitation of calcium carbonate is induced by certain microbes under suitable environmental conditions. S. pasteurii has assumed importance in recent years due to its identification as a possible agent for inducing significant volumes of MICP under certain conditions. This possibility stems from the fact that S. pasteurii has the unique ability to secrete copious amounts of the enzyme urease. This enzyme acts as a catalyst, promoting an accelerated lysis of urea (a naturally occurring biochemical compound with widespread and abundant supply) in the presence of water molecules. Through a cascade of reactions, this process ultimately leads to the generation of negatively charged carbonate ions. These ions, in turn, react with positive metal ions like calcium to finally form precipitates of calcium carbonate (calcite); hence the label MICP5-9.
The process of MICP has been known and studied for several decades10,11. Over the past few years, MICP has been investigated for a wide range of engineering and environmental applications including bottom-up green construction12, enhancement of large-scale structures13,14 and carbon sequestration and storage15,16.
For example, Cunnigham17 et. al designed a high pressure moderate temperature flow reactor containing a Berea sandstone core. The reactor was inoculated with the bacteria S. fridgidimarina and under conditions of high-pressure supercritical carbon dioxide injection, a massive accumulation of biomass inside the pore volumes was observed, which led to more than 95% reduction in permeability. Jonkers and Schlangen18 studied the effect of certain special strains of bacteria on the self-healing process in concrete. External water transported into the pore network entering through the surface pores is expected to activate the dormant bacteria which in turn help structural strength via MICP. Tobler19 et al. have compared the ureolytic activity of S. pasteurii with an indigenous groundwater ureolytic microcosm under conditions favoring large-scale MCIP and found that S. pasteurii has a consistent capability to improve calcite precipitation even when the indigenous communities lacked prior urease activity. Mortensen20 et.al have studied the effects of external factors like soil type, concentration of ammonium chloride, salinity, oxygen concentration and lysis of cells on MICP. Their demonstration that the biological treatment process is very robust with respect to a wide variation in parameter space substantiates the fitness of this process for various large-scale remediation applications provided a proper enrichment process to reinforce the bacteria is undertaken. Phillips21 et. al designed experiments to study the changes in permeability and strength of a sand column and a sandstone core after being injected with S. pasteurii cultures. They found that while the permeability decreased 2 - 4 times while the fracture strength increased three times.
S. pasteurii and its role in MICP are topics of active research and several issues relating to the mechanism of chemical precipitation are still not fully understood. In light of this, it is very important to have a set of consistent standardized protocols to accurately culture a suitably enriched stock of S. pasteurii to achieve MICP. Here, we outline a rigorous protocol that will ensure repeatability and reproducibility. This manuscript describes the detailed protocols for culturing S. pasteurii and suitably enriching the culture medium to induce precipitation. The process is investigated through various microscopic techniques such as optical and Scanning Electron Microscopy (SEM) and X-Ray Photo-electron Spectroscopy (XPS). The focus of the manuscript is on the process of MICP. Procedures like SEM and SIMS, being well-established standard protocols, are not described separately.

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			<td height="21" style="height:21px;width:224px;">Petridish</td>
			<td style="width:108px;">Fisher Scientific</td>
			<td style="width:119px;">FB0875712</td>
			<td style="width:255px;">Petridishes being used as Agar plate</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:224px;">Pyrex Flasks</td>
			<td>Fisher Scientific</td>
			<td style="width:119px;">S63268</td>
			<td style="width:255px;">Corning Erlenmeyer</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:224px;">Tris-Base</td>
			<td style="width:108px;">Promega</td>
			<td style="width:119px;">H5133</td>
			<td style="width:255px;">being used to make Tris-Buffer</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:224px;">Hydrochloric Acid</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">H9892</td>
			<td style="width:255px;">1.0 N, Bioreagent, suitable for cell culture</td>
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		<tr height="63">
			<td height="63" style="height:63px;width:224px;">Agar Powder</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">A1296</td>
			<td style="width:255px;">microbiology tested, plant cell culture tested, cell culture tested, powder</td>
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		<tr height="21">
			<td height="21" style="height:21px;">Ammonium Sulphate</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">A4418</td>
			<td style="width:255px;">for Molecular Biology</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:224px;">Yeast extract powder</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">51475</td>
			<td style="width:255px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:224px;">Measuring Cylinder</td>
			<td style="width:108px;">Cole-Parmer</td>
			<td style="width:119px;">CP08559GC</td>
			<td style="width:255px;">Cole-Parmer Class A Graduated Cylinder w/Cal Cert,TC;1000ml,1/Pk</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:224px;">Analytical Balance</td>
			<td style="width:108px;">OHAUS</td>
			<td style="width:119px;">AX124E</td>
			<td style="width:255px;">being used to measure weight of reagents</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:224px;">Autoclave</td>
			<td style="width:108px;">Brinkmann</td>
			<td style="width:119px;">58619000</td>
			<td style="width:255px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:224px;">Autoclave Tape</td>
			<td style="width:108px;">VWR</td>
			<td style="width:119px;">52428864</td>
			<td style="width:255px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:224px;">Aluminum Foil</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">Z185140</td>
			<td style="width:255px;">being used to seal the flask before placing it in Autoclave</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:224px;">Bacterial Stock</td>
			<td style="width:108px;">Cedarlane</td>
			<td style="width:119px;">11859</td>
			<td style="width:255px;">-80&#176;C stock of S. pasteurii, ATCC No. is mentioned against Cat. No.</td>
		</tr>
		<tr height="40">
			<td height="40" style="height:40px;width:224px;">Mline Single-Channel Mechanical Pipettors, Variable Volume</td>
			<td style="width:108px;">Biohit</td>
			<td style="width:119px;">725010</td>
			<td style="width:255px;">Marketed by VWR under catalog number 14005976</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:224px;">Micropipette Tip</td>
			<td>Fisher Scientific</td>
			<td style="width:119px;">212772B</td>
			<td style="width:255px;">Used for scratching Agar plates</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:224px;">Incubator</td>
			<td style="width:108px;">Binder</td>
			<td style="width:119px;">80079098</td>
			<td style="width:255px;">Microbiology Incubator,BF Series</td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:224px;">Shaking Incubator</td>
			<td style="width:108px;">VWR</td>
			<td style="width:119px;">14004300</td>
			<td style="width:255px;">VWR Signature Benchtop Shaking Incubators</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;">Phosphate Buffer Saline (PBS)&#160;</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">P7059</td>
			<td style="width:255px;"></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:224px;">BD Falcon Express Pipet-Aid Pipetting Device</td>
			<td style="width:108px;">BD Biosciences</td>
			<td style="width:119px;">357590</td>
			<td style="width:255px;">Marketed by VWR under catalog number 53106220</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:224px;">Parafilm</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">P7793</td>
			<td style="width:255px;">Being used to seal Agar plates</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:224px;">Urea</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">U1250</td>
			<td>Enrichment for nutrient medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:224px;">Sodium Bicarbonate</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">S8875</td>
			<td>Enrichment for nutrient medium</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:224px;">Calcium chloride</td>
			<td style="width:108px;">Sigma-Aldrich</td>
			<td style="width:119px;">C1016</td>
			<td>Enrichment for nutrient medium</td>
		</tr>
	</tbody>
</table>

microbiologically induced calcite precipitation mediated by sporosarcina pasteurii

The particular bacterium under investigation here (S. pasteurii) is unique in its ability, under the right conditions, to induce the hydrolysis of urea (ureolysis) in naturally occurring environments through secretion of an enzyme urease. This process of ureolysis, through a chain of chemical reactions, leads to the formation of calcium carbonate precipitates. This is known as Microbiologically Induced Calcite Precipitation (MICP). The proper culture protocols for MICP are detailed here. Finally, visualization experiments under different modes of microscopy were performed to understand various aspects of the precipitation process. Techniques like optical microscopy, Scanning Electron Microscopy (SEM) and X-Ray Photo-electron Spectroscopy (XPS)&#160;were employed to chemically characterize the end-product. Further, the ability of these precipitates to clog pores inside a natural porous medium was demonstrated through a qualitative experiment where sponge bars were used to mimic a pore-network with a range of length scales. A sponge bar dipped in the culture medium containing the bacterial cells hardens due to the clogging of its pores resulting from the continuous process of chemical precipitation. This hardened sponge bar exhibits superior strength when compared to a control sponge bar which becomes compressed and squeezed under the action of an applied external load, while the hardened bar is able to support the same weight with little deformation.

S. pasteurii being an alkaliphile24 can survive relatively harsh conditions. When the above mentioned culture protocol is followed, and S. pasteurii is grown inside a chamber, the bacteria leads to the precipitation of calcium carbonate over time (Figure 2A). Figure 2 (b) shows a phase-contrast optical microscopic image of the bacterial cell population within the culture medium. Individual cells can be clearly distinguished, w...

Watch this Scientific Journal Video about Microbiologically Induced Calcite Precipitation Mediated by Sporosarcina pasteurii at JoVE.com

Microbiologically Induced Calcite Precipitation Mediated by Sporosarcina pasteurii

Protocols for microbiologically induced calcite precipitation (MICP) using the bacterium Sporosarcina pasteurii are presented here. The precipitated calcium carbonate was characterized through optical microscopy and scanning electron microscopy (SEM). It is also shown that exposure to MICP increases the compressive strength of sponge.

Microbiologically Induced Calcite Precipitation Mediated by Sporosarcina pasteurii

The particular bacterium under investigation here (S. pasteurii) is unique in its ability, under the right conditions, to induce the hydrolysis of urea ...

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