Effect of cell density on decrease in hydraulic conductivity by microbial calcite precipitation

Abstract

The effect of number of cells deposited on decrease in hydraulic conductivity of porous media using CaCO3 precipitation induced by Sporosarcina pasteurii (ATCC 11,859) was examined in columns packed with glass beads in the range of 0.25 mm and 3 mm in diameter. After resting Sporosarcina pasteurii cells were introduced into the columns, a precipitation solution, which consisted of 500 mM CaCl2 and 500 mM urea, was introduced under continuous flow conditions. It was shown that hydraulic conductivity was decreased by formation of microbially induced CaCO3 precipitation from between 8.37 * 10−1 and 6.73 * 10−2 cm/s to between 3.69 * 10−1 and 1.01 * 10−2 cm/s. The lowest hydraulic conductivity was achieved in porous medium consisting of the smallest glass beads (0.25 mm in diameter) using the highest density of cell suspension (OD600 2.25). The number of the deposited cells differed depending on the glass bead size of the columns. According to the experiments, 7 * 10−9 g CaCO3 was produced by a single resting cell. The urease activity, which led CaCO3 precipitation, depended on presence of high number of cells deposited in the column because the nutrients were not included in the precipitation solution and consequently, the amount of CaCO3 precipitated was proportional with the cell number in the column. A mathematical model was also developed to investigate the experimental results, and statistical analysis was also performed.

Optimization of hydrogen production in Enterobacter aerogenes by Complex I peripheral fragments destruction and maeA overexpression

“…After the bacterial solution was properly diluted, the cell density (OD 600 ) was measured using a UV-visible spectrophotometer (Spectrolab 752 S, Shanghai Precision Scientific Instrument Co., Ltd., China). The dry weight was obtained from the standard curve of DCW versus OD 600 using the empirical formula: cell dry weight (g/L) = 0.132 × OD 600 [ 35 ]. The residual content of glucose in the fermentation broth was determined colorimetrically using the 3,5-dinitrosalicylic acid (DNS) method, and the pH value was measured using a conventional pH meter (Cheng Du Sunge Instrument Co., Ltd.) [ 36 ].…”

Transportation of Sporosarcina Pasteurii in Porous Media With Different Particle Sizes

“…Another of these influencing factors is cell density, which correlates with the urease enzyme [9]. According to Eryürük, the amount of bacterial precipitation can be expressed as a function of the bacterial biomass deposited in the column [18]. Therefore, it is critical to understand the transportation distance of cells through the column to achieve bacterial precipitation.…”