Application of Microbially Induced CaCO₃ on the Reinforcement of Rock Discontinuity

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The materials and methods used need to be reviewed in order to fully understand the physiological state of the bacteria used in the various experiments.

What's more, the results are rarely, if ever, compared with the literature, despite the existence of a wealth of literature in this field.

A great deal of work has been carried out on the use of MICP on concrete, yet there are no articles in the bibliography.

Why did the authors choose to use a soil bacterium and not a marine bacterium? Marine species are used for PCM.

Please don't use Microbes - This term doesn't really represent organisms in biological terms - it's better to use bacteria or micro-organisms.

The layout of the article needs to be revised. Parts 1 (Introduction) and 2 (Distribution of Catastrophic Ladslide under Saline-Akaline Conditions) could be made into a single part - Introduction.

Similarly, parts 3 -Materials and 4 - Methods may form a single Materials and Methods section.

 

Part 2.

Pleas note that Table 1 is not quoted

Part 3. Materials

This sentence "Sporosarcina pasteurii is a gram-positive bacterium known for its ability to produce urease by the process of microbiologically induced calcite precipitation from biological cementation" is not quite correct - It could be Sporosarcina pasteurii is a gram-positive bacterium known for its ability to induce calcite precipitation from biological cementation by the production of urease.

Specify the strain (number, origin....) of your bacteria

Specify the pH adjustment of the saline-alkaline medium

P5. It is stated that "The optimum density of Sporosarcina pasteurii was found to be 1.39" - why? for which experiment? The maximum optimum density is 1.421 in figure 8.

Why do you use a gelling liquid? Which component of your solution produces a gel?

"In order to compare the MICP performance of domestic bacteria, a neutral medium was prepared by removing MgSO4, KCL and MgCl2"-Why do you keep NaCl (the most concentrated salt).

 

Part 4  

Figure 3 and Table 3 could be combined to make one figure easier to understand.

If you read the article in its entirety, it is not very clear whether you wait only 48 hours between two consecutive transplants or whether you wait until you are in the stationary phase. If the waiting time between two transplantations is only 48 hours, why? Changing the culture conditions will inevitably increase the waiting time. Changing the culture to a solid medium might allow a better adaptation.

 

In addition, under what conditions are the mother suspensions prepared (medium, incubation time, OD, etc.)?

It will be very interesting to have the growth curve of each condition. A comparison between natural, direct domestication, three gradient domestication or five gradient domestication would be a plus.

Regarding Figure 5, stage 1 is referred to as the latent phase and stage 2 as the exponential growth phase.

 

Part 4.2 is not necessary.

 

If you're talking about your culture with bacteria, it's preferable to use the term bacterial suspension rather than bacterial solution.

 

Part 4.4

It is not clear about the age of the culture - do you keep the culture after domestication - do you use it immediately - more precision is needed.

Part 5.

Figure 8. This figure and the accompanying text are very difficult to understand - please explain the difference between the initial stage of domestication and the stable stage of domestication.

How many times does the stable phase of domestication last?

 

5.2 - MICP technology doesn't just use urea pathways - there are many other methods.

Figure 9. It is necessary to compare urease and DO activities. - Same problem as in Figure 8 regarding the initial, stable stage of domestication.

"During multi-gradient..... higher concentration". This paragraph needs to be improved to compare activity with OD. Furthermore, urease is located in the cytoplasm of the cell, which is normally at constant osmotic pressure. If the osmotic pressure outside the cell is altered, bacterial cells will modify their cell walls.

5.3 The values in the text do not correspond to the values in Table 5. Is this normal?

Author Response

Reviewer 1:

The materials and methods used need to be reviewed in order to fully understand the physiological state of the bacteria used in the various experiments.

Response: The content has been updated, and reference [52] has been added.

What's more, the results are rarely, if ever, compared with the literature, despite the existence of a wealth of literature in this field.

Response: We were unable to find any literature on the domestication of Sporosarcina pasteurii in a saline-alkaline environment, so we did not make any comparisons with other results. Different materials and mechanical surfaces will yield different peak shear strengths. The red sandstone examined in this study has not been previously studied for crack repair and peak shear strength measurement. Therefore, the results were not compared with the previous literature.

A great deal of work has been carried out on the use of MICP on concrete, yet there are no articles in the bibliography.

Response: References [27-34] were added in the revised manuscript.

Why did the authors choose to use a soil bacterium and not a marine bacterium? Marine species are used for PCM.

Response: The cracks we need to fill are within the rock. As rock and soil are found in terrestrial environments, we have selected bacteria from the soil. Among the many strains suitable for MICP, Sporosarcina pasteurii is well-suited to alkaline environments.  Therefore, domesticating Sporosarcina pasteurii can lead to ideal results.  Your question has prompted me to consider the selection of strains in another way, and I will thoroughly explore it in my future research.

Please don't use Microbes - This term doesn't really represent organisms in biological terms - it's better to use bacteria or micro-organisms.

Response: We have revised it in the manuscript.

The layout of the article needs to be revised. Parts 1 (Introduction) and 2 (Distribution of Catastrophic Ladslide under Saline-Akaline Conditions) could be made into a single part - Introduction.

Response: We have revised it.

Similarly, parts 3 -Materials and 4 - Methods may form a single Materials and Methods section.

Response: We have revised it.

Part 2.

Please note that Table 1 is not quoted

Response: Reference [50] has been added. Page 6, line 113.

Part 3. Materials

This sentence "Sporosarcina pasteurii is a gram-positive bacterium known for its ability to produce urease by the process of microbiologically induced calcite precipitation from biological cementation" is not quite correct - It could be Sporosarcina pasteurii is a gram-positive bacterium known for its ability to induce calcite precipitation from biological cementation by the production of urease.

Response: We have revised it. Page 6, lines 117-118.

Specify the strain (number, origin....) of your bacteria

Response: The strain was purchased from China General Microbial Culture Preservation Management Center (CGMCC), whose number is 1.3687. We've supplemented the strain information. Page 7, lines 132-133.

Specify the pH adjustment of the saline-alkaline medium

Response: In this experiment, the pH value of the medium was adjusted by 1mol/L NaOH solution and 1mol/L HCl solution. The pH of the solution was measured with a pH detector while adding NaOH or HCl solution until the desired value was reached. Page 7, lines 142-144.

P5. It is stated that "The optimum density of Sporosarcina pasteurii was found to be 1.39" - why? for which experiment? The maximum optimum density is 1.421 in figure 8.

Response: This section describes measurements of the first extended culture after bacterial activation.  There is a minimal discrepancy between the values in the subsequent results and this initial measurement, which is likely due to test error. To avoid confusion, it is recommended to disregard this initial value.

Why do you use a gelling liquid? Which component of your solution produces a gel?

Response: Due to the high concentration of each substance, the mixture is in a state of suspension, and the gelling liquid should be more accurately described as a suspension. This term has been revised in the text.

"In order to compare the MICP performance of domestic bacteria, a neutral medium was prepared by removing MgSO4, KCL and MgCl2"-Why do you keep NaCl (the most concentrated salt).

 Response: Both solutions contain NaCl. The NaCl concentration in the salt- alkaline environment should be should be 20g/L, while it should be 5g/L in the neutral environment, as modified in the paper. Page 8, line 154, and Table 2.

Part 4 

Figure 3 and Table 3 could be combined to make one figure easier to understand.

Response: We have revised it. All in Figure 3 and deleted Table 3.

If you read the article in its entirety, it is not very clear whether you wait only 48 hours between two consecutive transplants or whether you wait until you are in the stationary phase. If the waiting time between two transplantations is only 48 hours, why? Changing the culture conditions will inevitably increase the waiting time. Changing the culture to a solid medium might allow a better adaptation.

Response: The domestication process for each gradient is as follows: each culture requires 48 hours.  According to the law of bacterial growth, the concentration of bacteria is maintained at a high level, and the activity of unit urease will reach its maximum and gradually decrease after 48 hours of culture.  This experiment measured the maximum urease activity and maximum bacterial suspension concentration within 48 hours.  Each gradient acclimation will undergo multiple 48-hour bacterial cultures until the measured values of the preceding and subsequent two times are similar (we consider the results to be the same if the error range is less than 1% due to experimental errors). After 48 hours of culture, a large amount of nutrients in the medium have been consumed, which will cause the living environment of the bacteria to deteriorate further. Therefore, we believe that continuous nutrient supplementation and multiple domestications can expedite the domestication process. According the followed rock crack repair tests, the liquid bacteria should be filled to the cracks. Therefore, the liquid bacteria are more easily distributed evenly, requiring a liquid medium for the test. The corresponding explanation were added to the revised manuscript. Page 11, lines 218-224.

In addition, under what conditions are the mother suspensions prepared (medium, incubation time, OD, etc.)? mother suspensions

Response: The purchased strains are in freeze-dried powder form. The bacterial suspension used in the experiment was an activated bacterial suspension. The culture conditions of bacterial activation are: 30ºC, 150 rpm, about 5 days. After observing the turbidity of the bacterial solution, the mother solution was obtained by mixing the bacterial suspension with the neutral medium at a volume ratio of 1:100 for 48 hours. The OD600 value was 1.411. The corresponding text was added to the revised manuscript. Page 7, lines 135-139.

It will be very interesting to have the growth curve of each condition. A comparison between natural, direct domestication, three gradient domestication or five gradient domestications would be a plus.

Response: The bacteria reached a stable state after being cultured directly six times for 48 hours and domesticated 15 times using a 3-gradient method, and 20 times using a 5-gradient method. Due to space constraints in the paper, this content is not explained further. The figure below shows the value of the bacteria domesticated each time during the direct domestication process.

 

Regarding Figure 5, stage 1 is referred to as the latent phase and stage 2 as the exponential growth phase.

 Response: We have revised it. Page. 12, line 243.

Part 4.2 is not necessary.

Response: This is valuable advice. The content of sections 4.2 and 4.1 in the original text are similar, and we have combined them into section 3.1 in the revised manuscript.

If you're talking about your culture with bacteria, it's preferable to use the term bacterial suspension rather than bacterial solution.

Response: We have revised it.

Part 4.4

It is not clear about the age of the culture - do you keep the culture after domestication - do you use it immediately - more precision is needed.

Response: Domesticated bacteria are used directly, and some of them are retained as specimen strains for subsequent use.

Part 5.

Figure 8. This figure and the accompanying text are very difficult to understand - please explain the difference between the initial stage of domestication and the stable stage of domestication.

Response: The initial stage of domestication refers to the first domestication, while the stable domestication stage refers to the measurement error of the two domestications within 1%. To avoid any misunderstanding, a comment has been included in the text. Our lack of detailed description of domestication methods caused confusion among reviewers, so we added this part in Section 2.3. (Lines 224-228)

How many times does the stable phase of domestication last?

Response: The standard for bacteria to reach a stable state is when the value remains the same before and after two measurements. The measurements will show consistent results in a medium with the same concentration if the acclimation culture is performed again.

5.2 - MICP technology doesn't just use urea pathways - there are many other methods.

Response: Yes, we have revised it. Page. 17, lines 347-348.

Figure 9. It is necessary to compare urease and DO activities. - Same problem as in Figure 8 regarding the initial, stable stage of domestication.

Response: The initial stage of domestication refers to the first domestication, while the stable domestication stage refers to the measurement error of the two domestications within 1%. To avoid any misunderstanding, a comment has been included in the text. Our lack of detailed description of domestication methods caused confusion among reviewers, so we added this part in Section 2.3. (Lines 224-228)

"During multi-gradient..... higher concentration". This paragraph needs to be improved to compare activity with OD. Furthermore, urease is located in the cytoplasm of the cell, which is normally at constant osmotic pressure. If the osmotic pressure outside the cell is altered, bacterial cells will modify their cell walls.

Response: We have revised it. The change rule of maximum bacterial suspension concentration is similar to that of maximum unit urease activity, so we combine the two parts in the original text for analysis. This part was also added to section 3.1.

5.3 The values in the text do not correspond to the values in Table 5. Is this normal?

Response: To ensure accuracy, we have modified the data analysis description in Table 4 of the paper. Upon reviewing the data, we found inconsistencies in Table 6 of section 3.5, which have also been addressed. Furthermore, we are still working on locating additional data. If this does not address the issue raised by the reviewer, please inform us accordingly.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

This research involved experimental analysis conducted on cultivate Sporosarcina Pasteurii to examine the reinforcement effect of microbially induced calcium carbonate on rock joints in saline-alkaline environment. Artificial domestication schemes for the Sporosarcina Pasteurii in a saline-alkaline environment were employed to assess concentration of the microbes. Thereafter, the shear strength of the sandstone joints repaired by the MICP and its extent were evaluate. The findings demonstrated that laboratory extracted Sporosarcina Pasteurii can enhance and increase shear strength of jointed rock to some extent.

The manuscript is well organized and its structure is regular. In general, the paper is considered to have significant scientific points in describing and discussing the results useful in engineering reinforcement characteristics of jointed rocks. Based on these observations, I feel that the manuscript could be considered for publication. Thus, it is recommended that the paper incorporate minor revisions.

 

However, before its acceptance for publication I recommend some minor comments to the authors given below:

1.      Introduction was well outlined

2.      Methodology; why did the authors limit the domestication scheme to five-gradient domestication of Sporosarcina Pasteurii? Will microbes maintain a similar trend of concentration if the gradient increases?

3.      In Fig.10, the result showed demonstrated the repair ability of the strains after the five-gradient domestication was best and increase the peak shear strength of the rock joints to a greater extend. However, the extent of increase in the peak shear strength of the rock joints induced by five-gradient domestication is not different from that of undomesticated. To clear this, I recommend the author to consider increasing the process of gradient domestication.

4.      In section 6, the conclusions were well structured

5.      Were there any specific challenges or limitations encountered during the experiment or analysis?

6.      Limitations and Future Research: The article should briefly mentions the potential for future research, specific areas where further investigation is needed.

Comments on the Quality of English Language

The quality of English is good

Author Response

Reviewer 2:

This research involved experimental analysis conducted on cultivate Sporosarcina Pasteurii to examine the reinforcement effect of microbially induced calcium carbonate on rock joints in saline-alkaline environment. Artificial domestication schemes for the Sporosarcina Pasteurii in a saline-alkaline environment were employed to assess concentration of the microbes. Thereafter, the shear strength of the sandstone joints repaired by the MICP and its extent were evaluate. The findings demonstrated that laboratory extracted Sporosarcina Pasteurii can enhance and increase shear strength of jointed rock to some extent.

 

The manuscript is well organized and its structure is regular. In general, the paper is considered to have significant scientific points in describing and discussing the results useful in engineering reinforcement characteristics of jointed rocks. Based on these observations, I feel that the manuscript could be considered for publication. Thus, it is recommended that the paper incorporate minor revisions.

 

However, before its acceptance for publication I recommend some minor comments to the authors given below:

1. Introduction was well outlined.

Response: We are very grateful for this reviewer for his/her encouragement regarding our work.

2. Methodology; why did the authors limit the domestication scheme to five-gradient domestication of Sporosarcina Pasteurii? Will microbes maintain a similar trend of concentration if the gradient increases?

Response: The gradient domestication of bacteria can enhance their performance. Increasing the number of gradients will only lead to domesticated bacteria matching the ability of undomesticated bacteria in a neutral environment without any diminishment. The maximum concentration of bacterial suspension and the maximum unit urease activity of the five-gradient domesticated strains were slightly higher than those of the three-gradient domesticated strains. Considering time constraints, the authors concluded that further increasing the number of gradients would not significantly enhance the maximum concentration of bacterial suspension and the maximum unit urease activity, thus affirming that using five gradients is adequate.

3. In Fig.10, the result showed demonstrated the repair ability of the strains after the five-gradient domestication was best and increase the peak shear strength of the rock joints to a greater extend. However, the extent of increase in the peak shear strength of the rock joints induced by five-gradient domestication is not different from that of undomesticated. To clear this, I recommend the author to consider increasing the process of gradient domestication.

Response: Did the reviewer recommend increasing the number of cultures in each gradient acclimation process? If so, the article needs a more detailed explanation. The domestication process for each gradient is as follows: each culture requires 48 hours. According to the law of bacterial growth, the concentration of bacteria is maintained at a high level, and the activity of unit urease will reach its maximum and gradually decrease after 48 hours of culture. This experiment measured the maximum urease activity and maximum bacterial suspension concentration within 48 hours. Each gradient acclimation will undergo multiple 48-hour bacterial cultures until the measured values of the preceding and subsequent two times are similar (we consider the results to be the same if the error range is less than 1% due to experimental errors).

4. In section 6, the conclusions were well structured

Response: We are very grateful for this reviewer for his/her encouragement regarding our work.

5. Were there any specific challenges or limitations encountered during the experiment or analysis?

Response: The main challenge is that each round of domestication requires measurements every six hours for 48 hours, meaning no sleep. Additionally, the microbial domestication experiment involved multiple domestication cultures, requiring a significant amount of continuous work for 48 hours, posing another challenge.

6. Limitations and Future Research: The article should briefly mentions the potential for future research, specific areas where further investigation is needed.

Response: This paper uses artificial two-dimensional parallel cracks, while the actual engineering is mostly three-dimensional non-parallel cracks. In future studies, we plan to use rocks collected from the field to investigate natural three-dimensional fractures. We will also consider variations in the opening of natural fissures by constructing non-parallel fissures. Page 27, lines 535-538.

 

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

1. The work analyzes the effect of microbially induced calcium carbonate precipitation (MICP) on rock reinforcement in saline-alkaline environments.
2. Experiments were conducted to cultivate Sporosarcina pasteurii for the purpose of improving the reinforcing effect of microbially induced calcium carbonate on rock joints in saline-alkaline environments.
3. The evaluation of the shear resistance characteristics of rock joints reinforced with CaCO3, yielded results that indicate that after being domesticated in a saline-alkaline environment, the bacterial concentration reached more than 96% of that of a neutral environment .
4. It is necessary to specify the behavior of domesticated Sporosarcina pasteurii in various scenarios at temperatures between 10 and 30 °C in saline-alkaline conditions and thus be able to demonstrate its performance.
5. It is convenient to model the maximum shear resistance of rock joints reinforced with MICP as a function of the curing time and thus be able to evaluate the behavior of the resistance at the beginning, development and end of the process.
6. The references are appropriate to the context of the phenomenon studied.
7. It is timely to discuss the conditions under which the ultimate shear strength of cemented rock joints significantly exceeded that of uncemented rock joints.

Author Response

Reviewer 3:

1. The work analyzes the effect of microbially induced calcium carbonate precipitation (MICP) on rock reinforcement in saline-alkaline environments.

Response: This result is strongly confirmed in the revised manuscript.

2. Experiments were conducted to cultivate Sporosarcina pasteurii for the purpose of improving the reinforcing effect of microbially induced calcium carbonate on rock joints in saline-alkaline environments.

Response: This result is strongly confirmed in the revised manuscript.

3. The evaluation of the shear resistance characteristics of rock joints reinforced with CaCO3, yielded results that indicate that after being domesticated in a saline-alkaline environment, the bacterial concentration reached more than 96% of that of a neutral environment.

Response: This result is strongly confirmed in the revised manuscript.

4. It is necessary to specify the behavior of domesticated Sporosarcina pasteurii in various scenarios at temperatures between 10 and 30 °C in saline-alkaline conditions and thus be able to demonstrate its performance.

Response: The growth and reproduction of bacteria are influenced by environmental temperature. Typically, as the temperature rises, the bacteria's growth, reproduction rate, and urease activity increase. However, at high temperatures, the bacteria's growth, reproduction, and metabolism are inhibited. Conversely, at low temperatures, the development, reproduction, and metabolism of bacteria are also inhibited, thereby limiting the production of bacterial liquid(Please refer to the following literature). The reviewer's comments are very good, but this paper only added the measurement of calcium carbonate yield at 10 degrees Celsius at the time of the experiment. We will conduct a detailed and in-depth study on this issue in the follow-up research.

Reference: Lee Y S, Kim H J, Park W. Non-ureolytic calcium carbonate precipitation by Lysinibacillus sp. YS11 isolated from the rhizosphere of Miscanthus sacchariflorus. Journal of Microbiology, 2017, 55(6): 440-447.

5. It is convenient to model the maximum shear resistance of rock joints reinforced with MICP as a function of the curing time and thus be able to evaluate the behavior of the resistance at the beginning, development and end of the process.

Response: The reviewers made a good comment.  We performed a planned data merge and annotated it in Figure 13.

 

       (a)                                                               (b)                                                          (c)

Fig. 13. Variation of peak shear strength of MICP cemented rock joints with time under different domestication schemes:(a)σ_n = 0.05σ_c (b) σn = 0.1σ_c (c) σ_n = 0.2σ_c.

 

6. The references are appropriate to the context of the phenomenon studied.

Response: We are very grateful for this reviewer for his/her encouragement regarding our work and for valuable suggestions to improve the quality of the manuscript.

7. It is timely to discuss the conditions under which the ultimate shear strength of cemented rock joints significantly exceeded that of uncemented rock joints.

Response: We are very grateful for this reviewer for his/her encouragement regarding our work and for valuable suggestions to improve the quality of the manuscript.

 

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have taken most of the comments into account, which improves the understanding of the manuscript.. However, the discussion is still somewhat lacking.

Specific point :

P3 L 58 – It's not just academics, there are many patents on this subject - correct your sentence

P5 L88 – the ICL reference needs more details, which year?

P6 L110 – Please change urinary by urease

P6 L113 the objectives of the study must be state here

P7 L136_137Indicate the culture medium?

P7 L 142 Precise the pH value

 

P9 L190 figure 3 not 1

 Part 3 – Poor discussion compared with the wealth of literature on this subject. (only 3 articles cited).P17 L347 Sporosacrinia pasteurri in italics

 

Author Response

Reviewer 1:

Thank you very much for your thorough and patient review, which have obviously improved the quality of our manuscript. The following are responses to your comments.

The authors have taken most of the comments into account, which improves the understanding of the manuscript. However, the discussion is still somewhat lacking.

Response: We are very thankful to this reviewer. We added the discussion according to these suggestions. ((Lines 381-383, 395-398, 405-411).

P3 L 58 – It's not just academics, there are many patents on this subject - correct your sentence

Response: We have revised it in the manuscript (Line 59).

The sentence was modified as: “Many researches, including papers and patents etc., have utilized MICP technology to repair concrete cracks of varying widths and shapes [27-34].”

P5 L88 – the ICL reference needs more details, which year?

Response: Needful done in the revised version. Fig. 1 illustrates the global distribution of landslide events until 2023, based on data from ICL published over the years. (Lines 87-88). This figure was drawn based on data published by ICL over the years. The data comes from the website https://www.landslides.org.

P6 L110 – Please change urinary by urease

Response: We have revised it in the manuscript (Lines 112). Please check.

P6 L113 the objectives of the study must be state here

Response: We have added it in the manuscript (Lines 115-117).

The corresponding added text followed as: “In this study, the strains suitable for the saline-alkaline environment were obtained using domestication. The cracks in the saline-alkaline environment were filled by strains to increase the peak shear strength of rocks.”

P7 L136_137Indicate the culture medium?

Response: We have revised it (Lines 142-143).

The followed text was added in the revised manuscript: “The culture medium contained beef extract (5g/L), peptone (5g/L), and NaCl (5g/L).”

P7 L 142 Precise the pH value

Response: We have revised it (Lines 149-150).

P9 L190 figure 3 not 1

Response: We have revised it (Line 197)

Part 3 – Poor discussion compared with the wealth of literature on this subject. (only 3 articles cited).

Response: Now, there are 6 new references for comparison ([79,80,82,83,86,87]). The discussion compared with published papers were added in the revised manuscript, such as, Lines 381-383, 395-398, 405-411.

P17 L347 Sporosacrinia pasteurri in italics.

Response: We have revised it (Line 354).

 

References

[79] Zhang Y, Xu X, Liu S, Wang Y, Du J, Jiang NJJoRM, et al. Bacterial activity and cementation pattern in biostimulated MICP-treated sand-bentonite mixtures. 2024.

[80] Czajkowska A, Korsak D, Fiedoruk-Pogrebniak M, Koncki R, Strzelak KJT. Turbidimetric flow analysis system for the investigation of microbial growth. 2024;268:125303.

[82] M. Qian, Y. Zuo, Z. Chen, X. Yin, Y. Liu, W. Yang, Y. Chen, Crystallization of CaCO3 in aqueous solutions with extremely high concentrations of NaCl, Crystals. 2019;9 (12) :647

[83] Fan Q, Fan L, Quach W-M, Duan JJC, Composites C. The impact of seawater ions on urea decomposition and calcium car-bonate precipitation in the MICP process. 2024:105631.

[86] Hanif MS, Bouabdallah A, Shafqat MH, Mangi SJSJoE, Technology. The Effect of Microbially Induced Calcium Carbonate on the Strength of Concrete Joint Reinforced. 2024;1:162-74.

[87] Dong Z-H, Pan X-H, Tang C-S, Wang D-L, Wang R, Shi BJRM, et al. A Microbially Induced Magnesia Carbonation (MIMC) Method with Potential Application for Crack Healing of Sandstone Cultural Relics: Improving Interfacial Bonding Strength. 2024:1-17. [27] K. Van Tittelboom, N. De Belie, W. De Muynck, W. Verstraete, Use of bacteria to repair cracks in concrete. Cement Concrete Research. 2010; 40 (1): 157–166.

 

Again, we are very grateful to this reviewer for his/her valuable comments on our manuscript. Their comment increased the quality of the paper. We hope the revised version will be accepted for publication in this journal.

 

The word vision, please see the attachment.

Author Response File: Author Response.pdf