Antimicrobial Activities of Olive Oil Mill Wastewater Extracts against Selected Microorganisms
Round 1
Reviewer 1 Report
The purpose of this work was to effectively extract phenolic compounds from olive oil mill wastewater and extracts and to assess the possible antimicrobial properties of these compounds. The authors have identified some antimicrobial effect in all extracts. The work is succinct and to the point but I have a few observations:
Line 70: Add a paragraph
Figure 2: 3 g of GAE seems to be too much, please check the results.
Table 1 and 2: Statistical comparison is unclear. Explain it at table footer
Please review the document for further minor revisions.
Comments for author File: 
Comments.pdf
Author Response
Reviewer 1
The purpose of this work was to effectively extract phenolic compounds from olive oil mill wastewater and extracts and to assess the possible antimicrobial properties of these compounds. The authors have identified some antimicrobial effect in all extracts. The work is succinct and to the point but I have a few observations:
Line 70: Add a paragraph
Thank you, the paragraph was added (line 88-109)
Figure 2: 3 g of GAE seems to be too much, please check the results.
Thank you for the critical question. The data was rechecked and confirmed. The results were given per liter, and also the results obtained in this study showed similar characteristics to the OOMW that generated in some regions of Greece where is close to olive oil industry used in this study.
Papazi, A., Pappas, I., & Kotzabasis, K. (2019). Combinational system for biodegradation of olive oil mill wastewater phenolics and high yield of bio-hydrogen production. Journal of biotechnology, 306, 47-53.
Table 1 and 2: Statistical comparison is unclear. Explain it at table footer.
Thank you. The statistical comparison was revised “The letters indicate significant (p < 0.05) differences in all extracts with different dilutions for each microorganism.”
Please review the document for further minor revisions.
Thank you, the manuscript was revised throughout the text.
Author Response File: Author Response.pdf
Reviewer 2 Report
Authors present the research work entitled “Antimicrobial activities of olive oil mill wastewater extracts against selected microorganisms”, the results represent an alternative for the use of phenolic compounds from olive oil mill wastewater.
Here I present my comments and suggestions:
1. Abstract section should be improved, it does not represent the whole work.
2. Introduction section is well addressed.
3. M&M section:
· 2.1 I suggest including an arrow to the pointed process and indicated in the ext.
· 2.2 I suggest separating this section in solvent kind extraction, and improve the methods description
· 2.3. I recommend including more specific characterization of the extracts, HPLC or MS.
4. Results: I suggest including the structures of the possible compounds into the extracts.
5. There is not clear limit between results and discussion.
6. References about the topic should be updated
Author Response
Reviewer 2
Authors present the research work entitled “Antimicrobial activities of olive oil mill wastewater extracts against selected microorganisms”, the results represent an alternative for the use of phenolic compounds from olive oil mill wastewater.
Here I present my comments and suggestions:
1.Abstract section should be improved, it does not represent the whole work.
Thank you for your comments. Abstract was rewritten regarding the reviewer comments.
2.Introduction section is well addressed.
Thank you.
3.M&M section:
- 2.1 I suggest including an arrow to the pointed process and indicated in the ext.
Thank you for your suggestion. The process was described in the first paragraph of the Introduction. For this, we avoided being repeated the process. In addition, OOMW used in the study has been highlighted in Figure 1.
- 2.2 I suggest separating this section in solvent kind extraction, and improve the methods description
Thank you for your suggestion. Section 2.2 was subdivided with bullet points and the section was revised.
- 2.3. I recommend including more specific characterization of the extracts, HPLC or MS.
Thank you for your comments. A part of the project, authors are going to publish the profile of the extracts with additional data in future publish article.
4.Results: I suggest including the structures of the possible compounds into the extracts.
Thank you for your suggestion. Authors are planning to present MS profiles of OEs and their structures of some major compounds in the future publishment.
5.There is not clear limit between results and discussion.
Thank you, it was revised.
6.References about the topic should be updated
Thank you, the references were revised.
Author Response File: Author Response.pdf
Reviewer 3 Report
This paper examine the use of OOMW as a potential antimicrobial substrate and investigate the potential effects of three different solvents with different polarities in order to obtain phenolic rich extracts from OOMW and antimicrobial activities of these extracts were tested against ten different microorganisms Overall, the paper needs to be improved in terms of language writing as well as the content. Also, authors need to perform critical analysis and interpret all these studies and come up with a conclusion for each section. Some of the claims in the discussion were not supported by any reference . To conclude, this paper needs to revise it carefully before it can be considered in high impact journal.
Specific comment:
Abstract:
- the title is attractive and related to the current trends.
- An abstract it must be able to stand alone. So, the problem statement, aim, novelty and results of the study, all should be included into the one paragraph of abstract.
Introduction:
- Introduction should be covered the gap of the research. Must be improved in this section.
- Also,must be mention the important of this study to society, economy, environment as well as industry. There are some additional materials for authors to read: (1) Mitigation of CO2 emissions .Optimization of recovery processes; (2)the impact of the use of solvents in the environmet how affect.
- Problem statement of your introduction is not strong, need to discuss more about it.
- Line 78 Discuss more extractions methods and disadvantages of those
- Please check the citation base on the author guideline.
Summarize the current research novelty and objective of this work.
Material and Method:
- Please provide an additional figure to illustrate the process of the whole methodology.
- It would be good to report the physicochemical characterization (conductivity and infrared spectroscopy), the total polyphenols (Folin–Ciocalteu test) and the antioxidant activity (DPPH assay) of different fractions derived from OMW
- Determination of Electric Conductivity and Elemental Composition of Isolated Fractions should be included
- Moreover, determination of Minimum Inhibitory Concentration and Minimum Bactericidal and antimicrobial Concentration of OMW
- Except of extraction method for recovery of bioactive components innovative pressure-driven membrane process for the treatment of OMW that consists firstly of microfiltration (MF) followed by a reverse osmosis (RO) stage can be used.
Results and discussion:
- Manuscript should be written in a passive manner. Avoid using ‘we’ when writing.
- What is the significance of the results of the work? There's limited statistical analysis and justification in some data.
- The figures and images showed in the paper is in low resolution. Please provide higher quality of figures and images.
- Authors should pay attention to English grammar and sentence structure. The authors are suggested to edit the manuscript carefully before submission.
- The authors are encouraged to read this article for more information, Biochar production via pyrolysis of citrus peel fruit waste as a potential usage as solid biofuel
Conclusions
- Kindly improve to more concise with significant results, include the limitations and what can be done for the future studies.
References
- Kindly revise reference format according to the author guideline.
- Swine manure treatment technologies as drivers for circular economy in agribusiness: A techno-economic and life cycle assessment approach
.
Author Response
Reviewer 3
This paper examine the use of OOMW as a potential antimicrobial substrate and investigate the potential effects of three different solvents with different polarities in order to obtain phenolic rich extracts from OOMW and antimicrobial activities of these extracts were tested against ten different microorganisms. Overall, the paper needs to be improved in terms of language writing as well as the content. Also, authors need to perform critical analysis and interpret all these studies and come up with a conclusion for each section. Some of the claims in the discussion were not supported by any reference. To conclude, this paper needs to revise it carefully before it can be considered in high impact journal.
Specific comment:
Abstract:
-the title is attractive and related to the current trends.
Thank you.
-An abstract it must be able to stand alone. So, the problem statement, aim, novelty and results of the study, all should be included into the one paragraph of abstract.
Thank you for your valuable comment. The abstract was rewritten regarding the reviewer comments.
Introduction:
-Introduction should be covered the gap of the research. Must be improved in this section.
Thank you for the comment. Introduction part was revised.
-Also, must be mention the important of this study to society, economy, environment as well as industry. There are some additional materials for authors to read: (1) Mitigation of CO2 emissions. Optimization of recovery processes; (2) the impact of the use of solvents in the environmet how affect.
Thank you for your valuable comment. The positive and negative aspects of solvents and extraction processes will be the core of the next critical review paper.
-Problem statement of your introduction is not strong, need to discuss more about it.
Thank you, it was revised (line 118-125).
-Line 78 Discuss more extractions methods and disadvantages of those
Thank you, there have been several kinds of extraction methods. The comparison of solvents instead of extraction methods was given in detail according to the aim of the present study.
- Please check the citation base on the author guideline.
Thank you, the references were revised.
Summarize the current research novelty and objective of this work.
Material and Method:
-Please provide an additional figure to illustrate the process of the whole methodology.
Thank you, Figure 2 was given (page 5).
-It would be good to report the physicochemical characterization (conductivity and infrared spectroscopy), the total polyphenols (Folin–Ciocalteu test) and the antioxidant activity (DPPH assay) of different fractions derived from OMW - Determination of Electric Conductivity and Elemental Composition of Isolated Fractions should be included - Moreover, determination of Minimum Inhibitory Concentration and Minimum Bactericidal and antimicrobial Concentration of OMW. - Except of extraction method for recovery of bioactive components innovative pressure-driven membrane process for the treatment of OMW that consists firstly of microfiltration (MF) followed by a reverse osmosis (RO) stage can be used.
Thank you for your valuable suggestions. The authors are still conducting the same project and they will improve the process in further experiments then they will analyze them considering your comments. However, this article is mainly focusing on screening antimicrobial activities of OEs effectively. The antimicrobial activities will be investigated in detail including MIC/MBC values and antibiofilm activities of the OEs and publish in a future article.
Results and discussion:
-Manuscript should be written in a passive manner. Avoid using ‘we’ when writing.
Thank you for the correction. This was removed.
-What is the significance of the results of the work? There's limited statistical analysis and justification in some data.
Thank you for the comments. The statistical analysis of the results was detailed “The letters indicate significant (p < 0.05) differences in all extracts with different dilutions for each microorganism.”
-The figures and images showed in the paper is in low resolution. Please provide higher quality of figures and images.
Thank you. The qualities of figures were improved.
-Authors should pay attention to English grammar and sentence structure. The authors are suggested to edit the manuscript carefully before submission.
Thank you, the manuscript was revised throughout the text.
-The authors are encouraged to read this article for more information, Biochar production via pyrolysis of citrus peel fruit waste as a potential usage as solid biofuel
Thank you for sharing high quality paper.
Conclusions
-Kindly improve to more concise with significant results, include the limitations and what can be done for the future studies.
Thank you for the comment. Conclusion part was revised (page 12).
References
-Kindly revise reference format according to the author guideline.
The reference format was revised.
-Swine manure treatment technologies as drivers for circular economy in agribusiness: A techno-economic and life cycle assessment approach
Technoeconomic analysis and life cycle assessments of the OOMW will be core of the further research.
Author Response File: Author Response.pdf
Reviewer 4 Report
The article needs some revision to be suitable for publication
-The abstract should be informative and include the main findings.
-Language should be revised. It has plenty of grammatical errors as well as sentence-structure mistakes.
-Figures should be represented in higher resolution
- The introduction should be enriched with recent references (2017-2023)
- Some important references might be added and discussed
1. Najla, T., Habibi, M., Ammar, M.H., Abazza, L., Mhamdi, R. (2022). Olive Fruit by-Products: From Waste Streams into a Promising Source of Value-Added Products. In: Ramadan, M.F., Farag, M.A. (eds) Mediterranean Fruits Bio-wastes. Springer, Cham. https://doi.org/10.1007/978-3-030-84436-3_3
2. El Asri, O., Fadlaoui, S., Ramdani, M. (2022). Anaerobic Digestion Technology of Solid and Liquid Forms of Olive Wastes in the Mediterranean Region. In: Ramadan, M.F., Farag, M.A. (eds) Mediterranean Fruits Bio-wastes. Springer, Cham. https://doi.org/10.1007/978-3-030-84436-3_4
3. Haouas, A. et al. (2022). Olive Waste as a Promising Approach to Produce Antioxidants, Biofertilizers and Biogas. In: Ramadan, M.F., Farag, M.A. (eds) Mediterranean Fruits Bio-wastes. Springer, Cham. https://doi.org/10.1007/978-3-030-84436-3_6
4. Delgado, A., Chammem, N., Issaoui, M., Ammar, E. (2023). Bioactive Phytochemicals from Olive (Olea europaea) Processing By-products. In: Ramadan Hassanien, M.F. (eds) Bioactive Phytochemicals from Vegetable Oil and Oilseed Processing By-products. Reference Series in Phytochemistry. Springer, Cham. https://doi.org/10.1007/978-3-030-91381-6_10
Author Response
Thank you for your comments. The abstract and the manuscript were revised throughout the text. Figures were improved and a graphical abstract was added. Thank you for sharing the high-quality papers.
Round 2
Reviewer 2 Report
The research work has the potential to be useful for application. Nevertheless, the short part presented here as a research paper has a considerable lack of information. It is important to present at least few argumentas about the effects of found compounds or previously reported.
Author Response
Thank you for your comments. The potential effects of bioactive compounds found in OOMW were discussed in the Results and Discussion (line 373-382).
Reviewer 3 Report
The paper has been improved. So I think that revised version of manuscript should be accepted.
Author Response
Thank you for your comments.
Reviewer 4 Report
The revised version could be accepted
Author Response
Thank you for your interest.
Round 3
Reviewer 2 Report
Dear authors,
Thank you for addressing almost all my suggestions. I still have some recommendations.
Please correct the " Results " section; it should be Results and Discussion. You put it all together, but it is not clear in the title of this section.
Please update the references. There are some relevant articles you can consider. You are not taking the most recent advances.
Author Response
Thank you for your interest. The title of "Results" was revised as "Results and Discussion". The reference list was also updated.
