Event Title

An Evaluation in Adherence of Bacillus and Streptomyces in Bio-cementation

Location

CSU Ballroom

Start Date

18-4-2016 10:00 AM

End Date

18-4-2016 11:30 AM

Student's Major

Biological Sciences

Student's College

Science, Engineering and Technology

Mentor's Name

Dorothy Wrigley

Mentor's Department

Biological Sciences

Mentor's College

Science, Engineering and Technology

Description

In nature, numerous bacteria can synthesize calcite crystal products which are often used to stabilize structures or produce cement. Substrates, like urea, which when hydrolyzed produce NH4+ and CO32-, are reported to enhance calcite precipitation. In order to have these bacteria produce calcite where it is desired, the bacteria must stay where placed for both growth and the production of calcite. This research examined the degree of initial attachment of different bacterial calcite-producing species (Bacillus and Streptomyces) to a carbonate glass and sand-column in syringes under different pH, urea and sodium chloride concentrations by using crystal violet staining and water retention assay. It also evaluated the effectiveness of attachment by Bacillus and Streptomyces alone and in combination. Syringes filled with sand were inoculated with bacteria, incubated, and assayed for water retention caused by bacterial activities. The results showed that the calcite-producing bacteria adhered best at pH 8.5 and 0.5 mg/L sodium chloride concentration increases the strength of the attachment. Urea appeared to have no critical role in this process. Culture of the bacteria in sand columns slowed water percolation through the column. Water was retained most when the sand-column is inoculated with both species. The combination of the bacteria also enhances the attachment of the organisms to carbonate glass compared to individual species; however, the optimum ratio between these two species in inoculum is not determined yet.

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Apr 18th, 10:00 AM Apr 18th, 11:30 AM

An Evaluation in Adherence of Bacillus and Streptomyces in Bio-cementation

CSU Ballroom

In nature, numerous bacteria can synthesize calcite crystal products which are often used to stabilize structures or produce cement. Substrates, like urea, which when hydrolyzed produce NH4+ and CO32-, are reported to enhance calcite precipitation. In order to have these bacteria produce calcite where it is desired, the bacteria must stay where placed for both growth and the production of calcite. This research examined the degree of initial attachment of different bacterial calcite-producing species (Bacillus and Streptomyces) to a carbonate glass and sand-column in syringes under different pH, urea and sodium chloride concentrations by using crystal violet staining and water retention assay. It also evaluated the effectiveness of attachment by Bacillus and Streptomyces alone and in combination. Syringes filled with sand were inoculated with bacteria, incubated, and assayed for water retention caused by bacterial activities. The results showed that the calcite-producing bacteria adhered best at pH 8.5 and 0.5 mg/L sodium chloride concentration increases the strength of the attachment. Urea appeared to have no critical role in this process. Culture of the bacteria in sand columns slowed water percolation through the column. Water was retained most when the sand-column is inoculated with both species. The combination of the bacteria also enhances the attachment of the organisms to carbonate glass compared to individual species; however, the optimum ratio between these two species in inoculum is not determined yet.

Recommended Citation

Pham, Anh and Hee Son. "An Evaluation in Adherence of Bacillus and Streptomyces in Bio-cementation." Undergraduate Research Symposium, Mankato, MN, April 18, 2016.
http://cornerstone.lib.mnsu.edu/urs/2016/poster-session-A/16