Preliminary Study of Bioelectricity Generation Using Lettuce Waste as Substrate by Microbial Fuel Cells

Round 1

Reviewer 1 Report

The study of the authors is relevant and is current as related to alternative fuel that is renewable and sustainable.

-I suggest a rephrase of the title as: Preliminary investigation of lettuce waste as substrate for electricity generation in microbial cells

-The author did not need to put "full stop" at the end of the title

-Abstract:

line 19-21: -Re-write this part?

INTRODUCTION

This part of manuscript is weakly discussed. Please update the information and let there be flow of thoughts of the review literature. 

-Line 76-77: -incomplete sentence?

-line 77: -What is CCMs? Not defined at all

-line 100-101: Recast the objective? How will you observe the potential of lettuce?

-line 108-110: -Not all farmers are literate so the feasibility of recommending lettuce as waste for electricity may not go well with them. You can only recommend that farmers will be able to provide lettuce waste as substrate to companies thereby making money out of waste.

line 121-124: Can you make figure 1 more real? Please show the actual microbial fuel cell chamber in your laboratory

line 124: Figure numbering looks wrong. What is Figure 01?

line 146: What do you mean by conventional microbiology techniques?

line 153-154: Font size here is different from the rest

line 258-260: Figure 4a? Please remove the table and let it stand alone if is passing any different information apart from what figure 4a represent?

-line 316-Why is the references standing alone?

line 334: The microbial name should be italic?

RESULTS AND DISCUSSION

Please compare your results previous study. Present using Table.

CONCLUSION

The conclusion of the manuscript should be updated. It looks to scanty and not well situated.

 

 

Comments for author File: Comments.pdf

The authors should re-check the grammatical structure of the manuscript again and re-edited moderately.

Author Response

Dear colleague, the authors appreciate the comments made to improve the manuscript.
The responses to each of the suggestions were made:
-I suggest a rephrase of the title as: Preliminary investigation of lettuce waste as substrate for electricity generation in microbial cells
Ans. The title was changed to Preliminary study of bioelectricity generation using lettuce waste as substrate in microbial fuel cells.
-The author did not need to put "full stop" at the end of the title
Ans. It was fixed.
-Abstract:
line 19-21: -Re-write this part?
Ans. It was rewritten.
INTRODUCTION
This part of the manuscript is weakly discussed. Please update the information and let there be flow of thoughts from the review literature.
-Line 76-77: -incomplete sentence?
Ans. It was fixed.
-line 77: -What is CCMs? Not defined at all
Ans. It was fixed. There was an error in the translation, the initials are MFC and correspond to Microbial Fuel Cells.
-line 100-101: Recast the target? How will you observe the potential of lettuce?
Ans. The entire sentence was corrected.
-line 108-110: -Not all farmers are literate so the feasibility of recommending lettuce as waste for electricity may not go well with them. You can only recommend that farmers will be able to provide lettuce waste as substrate to companies thereby making money out of waste.
Ans. To clarify this point we decided to write the following sentence: However, transferring this technology to farmers in places where illiteracy exists can be challenging.
line 121-124: Can you make figure 1 more real? Please show the actual microbial fuel cell chamber in your laboratory
Ans. In the photos taken, they are not appreciated in great detail as in the schematization used in Figure 1. The photos that are available are like those in Fig.2 a or Fig. 5.
line 124: Figure numbering looks wrong. What is Figure 01?
Ans. was fixed
line 146: What do you mean by conventional microbiology techniques?
Ans. Conventional microbiology techniques are already standardized and widely used in any microbiology laboratory, we decided to use these terms to summarize specifications of techniques that are already known in this area (microbiology).
line 153-154: Font size here is different from the rest
Ans. It was fixed.
line 258-260: Figure 4a? Please remove the table and let it stand alone if it is passing any different information apart from what figure 4a represents?
Ans. The table was shortened, the importance of the table is because the reviewers suggest putting it.
-line 316-Why is the references standing alone?
Ans. It was fixed.
line 334: The microbial name should be italic?
Ans. It was fixed.
RESULTS AND DISCUSSION
Please compare your results previous study. Present using Table.
Ans. The suggested was done.
CONCLUSION
The conclusion of the manuscript should be updated. It looks to scanty and not well situated.
Ans. Writing was improved.

Best regards

Author Response File: Author Response.pdf

Reviewer 2 Report

The study needs a profound reformulation, as the authors mix results with methods. For example, lines 221, 222 and 223 contain the following: “To calculate the internal resistance of the MFC-SC, Ohm's Law (V=IR) was used, where the voltage values were placed on the “y” axis and those of the electric current on the “x” axis, which when performing a linear adjustment, the slope of the line is the internal resistance of the system, see Figure 4a.”, and this information will belong to a section of methods and not of results.

Another deeply relevant aspect is the fact that the authors only present descriptive results (requiring a statistical analysis of the data).

On the other hand, the study has many gaps in terms of presenting results, since the authors never even explain what it means, for example, “0.348 ± 0.005” – is it the mean ± standard deviation? Or mean ± standard error of mean?

Moderate editing of English language required

Author Response

Dear colleague, the authors appreciate the comments made to improve the manuscript.
The responses to each of the suggestions were made:
The study needs a profound reformulation, as the authors mix results with methods. For example, lines 221, 222 and 223 contain the following: “To calculate the internal resistance of the MFC-SC, Ohm's Law (V=IR) was used, where the voltage values were placed on the “y” axis and those of the electric current on the “x” axis, which when performing a linear adjustment, the slope of the line is the internal resistance of the system, see Figure 4a.”, and this information will belong to a section of methods and not of results .
Ans. Corrected and rewritten.
Another deeply relevant aspect is the fact that the authors only present descriptive results (requiring a statistical analysis of the data).
Ans. The mean and standard deviation were placed on each graph.
On the other hand, the study has many gaps in terms of presenting results, since the authors never even explain what it means, for example, “0.348 ± 0.005” – is it the mean ± standard deviation? Or mean ± standard error of mean?
Ans. Fixed, it is the mean ± standard deviation. This was clarified in section 2.3 and added: The voltage values were presented with the mean ± standard deviation.

kind regards

Author Response File: Author Response.pdf

Reviewer 3 Report

The Authors here report a scorching topic about generating bioelectricity utilizing sustainable material (lettuce waste). The authors deal with the subject reasonably.  They get good results from the designed single Microbial fuel cell, which gives a current increase  till the 14^thday then fall in 30^stday. They tested different parameters to get the optimized conditions.

In my opinion, this work can be accepted as it is. 

 

Author Response

Dear colleague, the authors appreciate the comments made.

Best regards

Round 2

Reviewer 1 Report

The authors have improved on the manuscript.  However  authors should respond point by point to the my earlier review report. 

Author  should do a recheck 

Author Response

Dear colleague, I hope you are very well.
Thank you very much for the comments made.
It seems that there was an error, but the authors answered each of the points; maybe it was sent wrong.
We resend the responses with the corrected manuscript.

The study of the authors is relevant and is current as related to alternative fuel that is renewable and sustainable.
-I suggest a rephrase of the title as: Preliminary investigation of lettuce waste as substrate for electricity generation in microbial cells
Ans. The title was changed to Preliminary study of bioelectricity generation using lettuce waste as substrate in microbial fuel cells.
-The author did not need to put "full stop" at the end of the title
Ans. It was fixed.
-Abstract:
line 19-21: -Re-write this part?
Ans. It was rewritten (lines 19-22)
INTRODUCTION
This part of the manuscript is weakly discussed. Please update the information and let there be flow of thoughts from the review literature.
-Line 76-77: -incomplete sentence?
Ans. It was fixed.
-line 77: -What is CCMs? Not defined at all
Ans. It was fixed. There was an error in the translation, the initials are MFC and correspond to Microbial Fuel Cells.
-line 100-101: Recast the target? How will you observe the potential of lettuce?
Ans. The entire sentence was corrected.
-line 108-110: -Not all farmers are literate so the feasibility of recommending lettuce as waste for electricity may not go well with them. You can only recommend that farmers will be able to provide lettuce waste as substrate to companies thereby making money out of waste.
Ans. To clarify this point we decided to write the following sentence: However, transferring this technology to farmers in places where illiteracy exists can be challenging. (lines 104-105), because basically this technology could be used mostly by agro-industrial companies that generate a large amount of biomass in the form of waste, on the other hand, although there is illiteracy in certain areas, which represents a challenge, but the use of the MFC is practical.
line 121-124: Can you make figure 1 more real? Please show the actual microbial fuel cell chamber in your laboratory
Ans. Figure 1 is a representative schematic of a scMFC, however, the actual microbial combustion cells can be seen in Figure 5.
line 124: Figure numbering looks wrong. What is Figure 01?
Ans. was fixed
line 146: What do you mean by conventional microbiology techniques?
Ans. Conventional microbiology techniques are already standardized and widely used in any microbiology laboratory; we decided to use these terms to summarize technical specifications that are already known in this area (microbiology).
line 153-154: Font size here is different from the rest
Ans. It was corrected, it must have been a typing error.
line 258-260: Figure 4a? Please remove the table and let it stand alone if it is passing any different information apart from what figure 4a represents?
-line 316-Why is the references standing alone?
Ans. The format was corrected according to the magazine.
line 334: The microbial name should be italic?
Ans. It was fixed.
RESULTS AND DISCUSSION
Please compare your results previous study. Present using Table.
Ans. As suggested, a table was used to compare various electrical values obtained from other organic waste (table 1). Likewise, this was analyzed and discussed, where values of vegetable and fruit residues were chosen to compare the electrical parameters produced. (line 278-287)
CONCLUSION
The conclusion of the manuscript should be updated. It looks to scanty and not well situated.
Ans. The writing was improved, it was a typo.

kind regards

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear authors, presenting the mean and standard-deviation is not representative of a statistical data analysis. For example, when you say "Lettuce waste has higher electrical values than other vegetable waste [57,58,59], and lower than potato waste [37], and other fruits (kiwi and tangerine) [30,60], except pitahaya fruit waste, probably because the latter has antimicrobial properties which influence the voltage and density power values of the MFC [61]", are these differences statistically significant? And what is the dimension of "n"? On the other hand, there is still no material and methods section where the (statistical) methods used are described. Additionally, when presenting the results of the linear regression, these must be interpreted, that is, what is the meaning of the values that are in the table of figure 4a? In addition, it is necessary to add the p-value and the significance value used.

Minor editing of English language required.

Author Response

Dear colleague, I hope you are very well.
Thank you very much for the comments made. The suggested changes have been made and each of the questions answered:

The study needs a profound reformulation, as the authors mix results with methods. For example, lines 221, 222 and 223 contain the following: “To calculate the internal resistance of the MFC-SC, Ohm's Law (V=IR) was used, where the voltage values were placed on the “y” axis and those of the electric current on the “x” axis, which when performing a linear adjustment, the slope of the line is the internal resistance of the system, see Figure 4a.”, and this information will belong to a section of methods and not of results .
Ans. Corrected and rewritten.
Another deeply relevant aspect is the fact that the authors only present descriptive results (requiring a statistical analysis of the data).
Ans. The data analysis section (162-173) was added, where the statistical difference is determined based on confidence intervals using the means of lettuce waste and the means of other values obtained by other organic waste found in articles. Likewise, the size of the effect is determined, using Cohen's D, of the values obtained with others that were consulted in articles. The results and analysis can be found on lines 277-318
On the other hand, the study has many gaps in terms of presenting results, since the authors never even explain what it means, for example, “0.348 ± 0.005” – is it the mean ± standard deviation? Or mean ± standard error of mean?
Ans. Fixed, it is the mean ± standard deviation. This was clarified in section 2.3 and added: The voltage values were presented with the mean ± standard deviation.

kind regards

Author Response File: Author Response.docx

Round 3

Reviewer 2 Report

The corrections were made and the document is now much more complete and of superior quality. 

In addition, when the authors state that: "For the analysis of data of the continuous variables (voltage, current) Pearson's linear regression was used, employing the equation of the line the values of electrical resistance were cleared and the suitability of the regression model was verified using the coefficient of determination R² (0.99).", must remove the value of R², since the results are not presented in the material and methods section. The results must always be presented in the results section.

However, it remains to explain what "CI=95%" means in Table 2, given that a confidence interval is, as its name indicates, a range of values (and as it is in the following columns).

Minor editing of English language required.

Author Response

Dear colleague, I hope you are very well.
The authors appreciate the comments made, to culminate this stage each of the comments is answered:

In addition, when the authors state that: "For the analysis of data of the continuous variables (voltage, current) Pearson's linear regression was used, employing the equation of the line the values of electrical resistance were cleared and the suitability of the regression model was verified using the coefficient of determination R2 (0.99).", must remove the value of R2, since the results are not presented in the material and methods section. The results must always be presented in the results section.
Ans 1. Ok, it was corrected. The result was added in line 242-243.
However, it remains to explain what "CI=95%" means in Table 2, given that a confidence interval is, as its name indicates, a range of values (and as it is in the following columns).
Ans 2. CI=95%: This was a translation error; the correct form was 95% CI (95% confidence interval). However, the interval was corrected in Table 2 as you mention.

 

 

kind regards

 

kind regards

Author Response File: Author Response.pdf