Factors Affecting Improvement of Engineering Properties of MICP-Treated Soil Catalyzed by Bacteria and Urease

Zhao, Qi; Li, Lin; Li, Chi; Li, Mingdong; Amini, Farshad; Zhang, Huanzhen

doi:10.1061/(asce)mt.1943-5533.0001013

Cited by 319 publications

(135 citation statements)

References 21 publications

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“…The ion concentration of ammonia during the process of urea hydrolysis increases due to the urease, hence the electrical conductivity of urea‐bacterial solution increases proportionally to the amount of urease present (Zhao et al . ). Each bacterial isolate was grown overnight in nutrient broth medium at 32°C with shaking (130 rev min −1 ).…”

Section: Methodsmentioning

confidence: 97%

“…The hydrolysis of urea can be measured by quantifying the relative changes in conductivity over time when urea is exposed to purified urease enzyme (Duraisamy 2016). The ion concentration of ammonia during the process of urea hydrolysis increases due to the urease, hence the electrical conductivity of urea-bacterial solution increases proportionally to the amount of urease present (Zhao et al 2014). Each bacterial isolate was grown overnight in nutrient broth medium at 32°C with shaking (130 rev min À1 ).…”

Section: Urease Measurementmentioning

confidence: 99%

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Assessing ureolytic bacteria with calcifying abilities isolated from limestone caves for biocalcification

Omoregie

Ong

Nissom

2018

Lett Appl Microbiol

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Biocalcification through the use of ureolytic bacteria and biochemical activities has evolved in recent decades into a fervent resourceful effective technology suitable for soil stabilization, crack repair and bioremediation. Extensive studies have been carried out on numerous ureolytic bacterial species isolated from soils and sewage samples. However, very limited attention has been given to limestone caves with natural calcite formations as a possible source for isolation of ureolytic bacteria. In this study, bacterial isolates were recovered from limestone cave samples to determine their suitability for biocalcification. Twenty‐seven morphologically distinct bacterial isolates were identified by partial 16S rRNA gene sequencing and their various genetic diversity was characterized according to their phylogenetic affiliations. Based on the molecular identification, Sporosarcina was the most abundant genus among all the ureolytic isolates, while the rest belonged to Pseudogracilibacillus and Bacillus genera. Analytical analysis on urease measurement showed that urease activities for the isolates ranged from 1·130 to 21·513 mol urea hydrolysed per minute, with isolate NB33 achieving the highest value and TSB4 achieving the lowest value. The estimated CaCO3 precipitates for the isolates ranged from 4·04 to 17·26 mg ml−1, with isolate NB30 achieving the highest value and TSB20 achieving the lowest value. The findings in this study demonstrated that the ureolytic bacteria from limestone caves are promising bio‐calcifying agents. Significance and Impact of the Study Ureolytic bacteria continues to play an important role as microbial tools used in geotechnical engineering for soil biocalcification. Microbial strains with the ability to produce urease enzyme and induce calcium carbonate mineral are often isolated from soil, water and sludge samples. However, screening for these essential microbes from extreme regions such as caves are rarely investigated. In this study, native bacteria which were isolated from limestone cave samples are identified and characterized. The findings suggested that these ureolytic bacterial isolates have the potential to serve as suitable alternative microbial agents for soil strengthening and stabilization.

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Section: Methodsmentioning

confidence: 97%

Section: Urease Measurementmentioning

confidence: 99%

Assessing ureolytic bacteria with calcifying abilities isolated from limestone caves for biocalcification

Omoregie

Ong

Nissom

2018

Lett Appl Microbiol

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“…Representative images of crystals inside six pores of this porous medium at the completion of the final cementation solution injection are also shown in this figure. The shape of the crystals was mainly prismatic, suggesting that the crystals might be calcite (Al Qabany et al, 2012;Zhao et al, 2014). Images of pores A to F at the completion of the 4 th , 8 th , 12 th , 16 th and 20 th injection of cementation solution are shown in Fig.…”

Section: Formation Of Cementation With Timementioning

confidence: 99%

A microfluidic chip and its use in characterising the particle-scale behaviour of microbial-induced calcium carbonate precipitation (MICP)

et al. 2019

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Microbial-Induced Calcium Carbonate Precipitation (MICP) is an innovative ground improvement technique which can enhance the strength and stiffness of soils and can also control their hydraulic conductivity. These engineering properties of MICP-treated soils are affected by the particle-scale behaviour of the precipitated calcium carbonate, i.e. composition, amount and distribution, which are controlled by the MICP process occurring at the particlescale. In this study, we designed and fabricated a microfluidic chip to improve our understanding of MICP at particle-scale by observing the behaviour of bacteria and calcium carbonate crystals during this process. We found that bacteria became evenly distributed throughout the microfluidic chip after the injection of bacterial suspension, grew during bacterial settling, and detached during the injection of cementation solution. Bacteria aggregated during the cementation solution injection, and calcium carbonate crystals formed at narrow pore throats or open pore bodies either during or after cementation solution injections.

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“…To date, the majority of studies of MICP have focussed on ureolytic bacteria (Zhu et al, 79 2016 Ureolytic MICP has been used in a range of applications. Positive outcomes were obtained 88 in the improvement of soil properties, however non-uniform rates of precipitation throughout 89 the samples led to varying results (Zhao et al, 2014). In addition, the requirement for 90 injection of the healing agent into the ground created problems where the rapid precipitation 91 initiated by urease activity caused clogging at the injection site (Cheng and Cord-Ruwisch, 92 2014).…”

Section: Introduction 35mentioning

confidence: 99%

EMIn-depth profiling of calcite precipitation by environmental bacteria reveals fundamental mechanistic differences with relevance to application

Reeksting

Hoffmann

Tan

et al. 2019

Preprint

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13 14 15 crystals, whereas the crystals of non-ureolytic strains were larger with a mixed 43 organic/inorganic composition. When representative strains were tested in application for 44 crack healing in cement mortars, non-ureolytic bacteria gave robust results, while ureolytic 45 strains showed more variation. This may be explained by our observation that urease activity 46 varied between growth conditions, or by the different nature and therefore material 47

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Factors Affecting Improvement of Engineering Properties of MICP-Treated Soil Catalyzed by Bacteria and Urease

Cited by 319 publications

References 21 publications

Assessing ureolytic bacteria with calcifying abilities isolated from limestone caves for biocalcification

Assessing ureolytic bacteria with calcifying abilities isolated from limestone caves for biocalcification

A microfluidic chip and its use in characterising the particle-scale behaviour of microbial-induced calcium carbonate precipitation (MICP)

EMIn-depth profiling of calcite precipitation by environmental bacteria reveals fundamental mechanistic differences with relevance to application

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