Sustainable Co-Production of Xylanase, Cellulase, and Pectinase through Agroindustrial Residue Valorization Using Solid-State Fermentation: A Techno-Economic Assessment

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Manuscript-2776722 is about a hot topic - biotechnological utilization of waste.Working in this way will create sustainability in the future. Eligible for the journal.

The main paradox of the work is the following: on the one hand, important economic indicators are calculated, on the other hand, it is not clear for which processes the main products - enzymes or their cocktails - are proposed.

The authors should sort out, for example, which cellulase is produced: cellobiohydrolase, endoglucanase, or maybe b-glucosidase? Or a cocktail of them? The same goes for xylanases. Table 2 mentions both endoxylanases and xylosidases. Which enzyme is their product closer to? The applications largely depend on this. Considering the rapid development of industrial biotechnology in the field of obtaining monocomponent preparations of carbohydrazases and efficient cocktails. What place in the market could the xylanases or cellulases proposed by the authors occupy?

Introduction

Requires considerable revision. A lot of general thoughts, about waste, enzymes. However, there is no specific justification, why BSG? What happens to the grain when receiving this biowaste? There is a lot of recent work on BSG, e.g. https://doi.org/10.1016/j.supflu.2023.105895 or https://www.mdpi.com/2311-5637/9/1/2. The authors have few references to such references.

Materials and methods

The component composition of the waste materials used is not specified, at least according to the literature. For example, BSG from which grain? Barley? Laboratory waste milling is used in this work. Is this process scalable in industry?

Results

Table 2 looks unplayable. Why are oxidoreductases listed there, if the article itself talks about carbohydrases? They differ considerably in cost and applicability. It is recommended to remove or substantially elaborate.

Conclusion

It is possible to shorten and still reflect in which industries these enzymes are supposed to be used.

Minor

Line 379 - amylase is not an LC-degrading enzyme.

Author Response

Reviewer #1:

 General comments to Reviewer 1

We highly appreciate the constructive comments of all reviewers. We apologize for the obvious format mistakes, and we thank you for noticing them. We have addressed every suggestion made. We revise the manuscript thoroughly and improved the writing. The new text additions and the revised sections are highlighted. We numbered each query and made changes in the text to answer all the suggested queries. The explanation provided next refers to the updated line numbers.

 

Reviewer´s Query “Introduction”

Requires considerable revision. A lot of general thoughts, about waste, enzymes. However, there is no specific justification, why BSG? What happens to the grain when receiving this biowaste? There is a lot of recent work on BSG, e.g. https://doi.org/10.1016/j.supflu.2023.105895 or https://www.mdpi.com/2311-5637/9/1/2. The authors have few references to such references.

 Reply to Query “Introduction”

The manuscript has been checked and corrected according to the reviewer´s recommendations. (Line 108-110)

 

Reviewer´s Query “Materials and methods”

The component composition of the waste materials used is not specified, at least according to the literature. For example, BSG from which grain? Barley? Laboratory waste milling is used in this work. Is this process scalable in industry?

 Reply to Query “Materials and methods”

I have reviewed the provided text and made some corrections to improve its clarity and grammar. Please find the revised text below:

The description has been updated with the type of grain used (Line 134). For milling, a bench scale mill was utilized. This process can be scaled up easily as there are mills available in the market with higher capacity that can be used without any issues.

Reviewer´s Query “Results”

Table 2 looks unplayable. Why are oxidoreductases listed there, if the article itself talks about carbohydrases? They differ considerably in cost and applicability. It is recommended to remove or substantially elaborate.

 Reply to Query “Results”

Thank you for highlighting the concern about Table 2. We recognize the potential confusion arising from the inclusion of oxidoreductases alongside carbohydrases, given their significant differences in cost and applicability. The decision to include oxidoreductases was driven by the limited availability of studies conducting techno-economic evaluations for their microbial production.

While our article primarily focuses on carbohydrases, we aimed to provide a more comprehensive overview by incorporating available data on oxidoreductases. We have included a statement in the results section to clarify our rationale. (Line 406-409).

 

Reviewer´s Query “Conclusion”

It is possible to shorten and still reflect in which industries these enzymes are supposed to be used.

Reply to Query 4

The conclusions were reduced as much as possible. However, other statements were added following all reviewers recommendations.

 

Reviewer´s Query “Minor”

Line 379 - amylase is not an LC-degrading enzyme

Reply to Query “Minor”

The sentence does not refer to amylase being an LC-degrading enzyme, but it was intended to list some enzymes that were included in the table, but to avoid naming all of them. The statement was rewritten. (Line 408)

Reviewer 2 Report

Comments and Suggestions for Authors

Recommendation: Major Revision

Comments to the Author

The topic of the manuscript is appropriately suited for publication. The manuscript is in general well written and organized. It provides a large amount of experimental data, and the work seems to be carefully executed. The authors used appropriate methods to address the aims and objectives of the study. The results obtained are also interesting and relevant. Overall, the study is technically solid and includes appropriate methods as well as pertinent results. However, and for the sake of full impact only, the authors are invited to consider the following list of suggestions and recommendations.

The reviewer has some specific comments/suggestions provided below.

Abstract:

·         The abstract is generally clear and well-structured. Consider adding a brief sentence emphasizing the importance or particular innovation of your study at the beginning of the abstract.

·         The mention of using sensors to monitor key parameters is excellent. To enhance understanding, perhaps provide a brief explanation of how these sensors contribute to the process monitoring.

·         The results obtained for Scenario 1 are well-detailed. Include a brief sentence indicating the expectations or initial objectives of the study before presenting the results.

·         The justification for evaluating the three scenarios is present. Add a sentence briefly explaining why these specific enzymes (xylanase, pectinase, cellulase) were chosen and why they are important.

·         The mention of optimization potential for Scenario 1 is interesting. Expand this section slightly to include other potential avenues for improvement or future extensions of the research.

·         The use of simulation to evaluate technico-economic feasibility is a strong point. Add a sentence explaining how these results could be applied or influence existing industrial practices.

·         The use of technical terms is appropriate. For non-specialist readers, ensure there is a brief explanation of key technical terms.

 

Section ( 1 Introduction) :

·         The introduction effectively highlights the generation of organic waste throughout the food supply chain. Consider briefly mentioning specific industries or sectors within the food supply chain to provide more context.

 

·         The mention of recycling, re-use, and re-valorization aligns with the concept of a circular economy. Elaborate on how these actions contribute to sustainability and the circular economy.

·         Clear definition of bio-waste is provided. Consider including examples of bio-waste from different origins for better illustration.

·         Emphasizing the importance of utilizing bio-waste as a renewable resource is crucial. Provide a brief example or case study illustrating the benefits derived from bio-waste utilization.

·         The explanation of plant bio-waste components generated during processing is informative. Provide a concise example or scenario showcasing the diversity of plant bio-waste.

·         The introduction of animal-origin bio-waste adds comprehensive coverage. Briefly mention specific industries or processes that generate animal-origin bio-waste.

·         The transition to discussing the role of bio-waste in bioprocesses is smooth. Consider providing a brief historical context or background on the use of bio-waste in bioprocesses.

·         Addressing the significance of cost in bioprocesses is essential. Offer a concise example illustrating the impact of bio-waste utilization on reducing bioprocess costs.

·         The shift in focus towards enzyme production is well-defined. Mention briefly the specific enzymes targeted and their industrial applications.

·         Providing context on the global market for enzymes adds relevance. Offer a sentence summarizing the growth trends or factors driving the demand for enzymes.

·         Highlighting challenges in enzyme production adds realism. Include a sentence on recent advancements or innovations addressing these challenges.

·         The breakdown of enzyme sourcing from microorganisms is informative. Briefly introduce the advantages or characteristics of fungi and bacteria in enzyme production.

·         Introducing the regional perspective adds a specific focus. Include a sentence on ongoing initiatives or projects related to biowaste utilization in the region.

·         Clearly stating the study's objective enhances clarity. Provide a brief rationale for selecting xylanase, cellulase, and pectinase as the target enzymes.

·         The mention of scaling up the solid-state fermentation process is crucial. Introduce a sentence briefly summarizing the benefits of solid-state fermentation in comparison to other techniques.

·         Naming specific substrates (BSG and AP) provides specificity. Include a sentence explaining why these particular substrates were chosen.

·         Introducing a packed column-type bioreactor with sensors is a key detail. Briefly explain the advantages of using a packed column-type bioreactor for large-scale production.

·         Discussing the economic feasibility adds a practical dimension. Provide a sentence on the potential economic implications for the region or industry.

 

Section (2.Methods) :

·         Raw Materials and Inoculum Preparation: Clear description of the raw materials (AP and BSG) and their preparation. Mention the quantities of AP and BSG used for the experiments for better understanding.

·         Microorganism Selection: The choice of Aspergillus sp. for solid-state fermentation is explained. Provide a brief rationale for selecting Aspergillus sp., emphasizing its suitability for the intended enzymatic production.

·         Bioreactor Design: The description of the packed-bed column bioreactor is thorough. Consider briefly explaining why a packed-bed column was chosen and its advantages over other bioreactor types.

·         Bioreactor Instrumentation: Detailed information on sensors used for monitoring CO₂, humidity, and temperature. Provide a brief justification for the choice of these specific sensors and their relevance to the fermentation process.

·         Cultivation Conditions: Clear details on the optimized process conditions for enzyme production. Consider briefly discussing the significance of the chosen conditions in enhancing xylanase synthesis.

·         Enzyme Recovery and Quantification: Well-explained steps for enzymatic extract recovery and quantification. Include a sentence discussing the importance of the chosen substrates (pectin, xylan, cellulose) in assessing enzyme activities.

·         Simulation Description: Comprehensive information on the simulation process and software used. Briefly mention why SuperPro Designer 10.3® was chosen for the techno-economic assessment.

·         Scenario Comparison: Clear delineation of three scenarios and their specific conditions. Include a sentence discussing the rationale behind choosing different scenarios and how they represent distinct optimization goals.

·         Techno-Economic Assessment: Well-detailed information on economic evaluation metrics and input parameters. Consider briefly discussing the expected impact of regional factors on the economic viability of the project.

·         Sensitivity Analysis: Comprehensive exploration of sensitivity analyses variables. Include a sentence discussing the significance of each variable and how it might impact the overall process profitability.

 

Section (3. Results) :

Your study provides a comprehensive investigation into enzyme production through fermentation using agro-industrial waste. Here are some comments and suggestions to enhance clarity and understanding:

·         Add a brief introduction before delving into the results, succinctly describing the study's objective and the context of enzyme production from agro-industrial waste.

·         Clarify the meaning of the values X, P, and C. Perhaps, mention the types of enzymes or compounds they represent.

·         Specify at the beginning of the section the overall context of the enzyme market and why xylanases, pectinases, and cellulases are particularly studied.

·         In the section on sensitivity analysis, ensure to include appropriate units of measurement for costs and prices.

·         Add a conclusions section summarizing the key findings of the study, highlighting implications, and providing recommendations.

·         Carefully proofread the text to correct any grammar, punctuation, or style errors.

Reference:

I noticed that the number of provided references (24) might benefit from expansion. For a work as interesting as yours, including additional references could further strengthen the robustness and credibility of your arguments.

I suggest considering the addition of relevant references that could enhance your discussion and shed light on specific aspects of your research.

 

Comments on the Quality of English Language

Moderate editing of English language required. 

·         Carefully proofread the text to correct any grammar, punctuation, or style errors.

Author Response

General comments to Reviewer 2

We highly appreciate the constructive comments of all reviewers. We apologize for the obvious format mistakes, and we thank you for noticing them. We have addressed every suggestion made. We revised the manuscript thoroughly and improved the writing. The new text additions and the revised sections are highlighted. We numbered each query and made changes in the text to answer all the suggested queries. The explanation provided next refers to the updated line numbers.

Comments to the authors: The topic of the manuscript is appropriately suited for publication. The manuscript is in general well written and organized. It provides a large amount of experimental data, and the work seems to be carefully executed. The authors used appropriate methods to address the aims and objectives of the study. The results obtained are also interesting and relevant. Overall, the study is technically solid and includes appropriate methods as well as pertinent results. However, and for the sake of full impact only, the authors are invited to consider the following list of suggestions and recommendations.

Abstract

Reviewer´s Query 1

The abstract is generally clear and well-structured. Consider adding a brief sentence emphasizing the importance or particular innovation of your study at the beginning of the abstract

Reply to Query 1

The sentence has been added according to the reviewer´s recommendations (Line 17-18).

 

Reviewer´s Query 2

The mention of using sensors to monitor key parameters is excellent. To enhance understanding, perhaps provide a brief explanation of how these sensors contribute to the process monitoring.

Reply to Query 2

The sentence has been added according to the reviewer´s recommendations (Line 23-25).

Reviewer´s Query 3

The results obtained for Scenario 1 are well-detailed. Include a brief sentence indicating the expectations or initial objectives of the study before presenting the results.

Reply to Query 3

The sentence has been added according to the reviewer´s recommendations (Line 30-31).

 

Reviewer´s Query 4

The justification for evaluating the three scenarios is present. Add a sentence briefly explaining why these specific enzymes (xylanase, pectinase, cellulase) were chosen and why they are important.

 Reply to Query 4

The sentence has been added according to the reviewer´s recommendations (Line 20-21).

 

Reviewer´s Query 5

The mention of optimization potential for Scenario 1 is interesting. Expand this section slightly to include other potential avenues for improvement or future extensions of the research.

 Reply to Query 5

The sentence has been added according to the reviewer´s recommendations (Line 38).

 

Reviewer´s Query 6

The use of simulation to evaluate technico-economic feasibility is a strong point. Add a sentence explaining how these results could be applied or influence existing industrial practices.

Reply to Query 6

The sentence has been added according to the reviewer´s recommendations (Line 39-40).

 

Reviewer´s Query 7

The use of technical terms is appropriate. For non-specialist readers, ensure there is a brief explanation of key technical terms.

 Reply to Query 7

The sentence has been added according to the reviewer´s recommendations (Line 33-34).

 

Section ( 1 Introduction)

 General comments for introduction

 After incorporating the recommendations and improving text flow and readability, the introduction has been significantly edited in response to all reviewer's queries.

 Reviewer´s Query 1

The introduction effectively highlights the generation of organic waste throughout the food supply chain. Consider briefly mentioning specific industries or sectors within the food supply chain to provide more context.

 Reply to Query 1

The information is presented in line 53-60.

 

Reviewer´s Query 2

The mention of recycling, re-use, and re-valorization aligns with the concept of a circular economy. Elaborate on how these actions contribute to sustainability and the circular economy.

Reply to Query 2

There are various ways to achieve a zero-waste circular economy. One of these involves companies that produce waste utilizing a biorefinery process to extract oils, sugars, proteins, and other materials to revalue the waste. The resulting material can be used for agricultural purposes or bio-composting to avoid the leaching of fertilizers and improve crop yields. Additionally, bio-waste can be used to generate green energy in the form of motor or heat energy to aid in processing. Few lines regarding the circular economy were added.

 

Reviewer´s Query 3

Clear definition of bio-waste is provided. Consider including examples of bio-waste from different origins for better illustration.

Reply to Query 3

The different origins of bio-residues are listed in lines 55 to 57.

 

Reviewer´s Query 4

Emphasizing the importance of utilizing bio-waste as a renewable resource is crucial. Provide a brief example or case study illustrating the benefits derived from bio-waste utilization.

Reply to Query 4

The information has been added according to the reviewer´s recommendations (Line 64-65).

 

Reviewer´s Query 5

The explanation of plant bio-waste components generated during processing is informative. Provide a concise example or scenario showcasing the diversity of plant bio-waste.

Reply to Query 5

The information has been added according to the reviewer´s recommendations (Line 54-60).

 

 

Reviewer´s Query 6

The introduction of animal-origin bio-waste adds comprehensive coverage. Briefly mention specific industries or processes that generate animal-origin bio-waste

Reply to Query 6

The information has been added according to the reviewer´s recommendations (Line 58-59).

 

Reviewer´s Query 7

The transition to discussing the role of bio-waste in bioprocesses is smooth. Consider providing a brief historical context or background on the use of bio-waste in bioprocesses.

Reply to Query 7

The information has been added according to the reviewer´s recommendations (Line 62-64).

 

Reviewer´s Query 8

Addressing the significance of cost in bioprocesses is essential. Offer a concise example illustrating the impact of bio-waste utilization on reducing bioprocess costs.

Reply to Query 8

The information has been added according to the reviewer´s recommendations (Line 68-71).

 

Reviewer´s Query 9

The shift in focus towards enzyme production is well-defined. Mention briefly the specific enzymes targeted and their industrial applications.

Reply to Query 9

The information is presented in line 122-124

 

Reviewer´s Query 10

Providing context on the global market for enzymes adds relevance. Offer a sentence summarizing the growth trends or factors driving the demand for enzymes.

Reply to Query 10

The information has been added according to the reviewer´s recommendations (Line 80-82).

 

Reviewer´s Query 11

Highlighting challenges in enzyme production adds realism. Include a sentence on recent advancements or innovations addressing these challenges.

Reply to Query 11

The information has been added according to the reviewer´s recommendations (Line 91-97).

 

Reviewer´s Query 12

The breakdown of enzyme sourcing from microorganisms is informative. Briefly introduce the advantages or characteristics of fungi and bacteria in enzyme production.

Reply to Query 12

The information has been added according to the reviewer´s recommendations (Line 91-94).

 

Reviewer´s Query 13

Introducing the regional perspective adds a specific focus. Include a sentence on ongoing initiatives or projects related to biowaste utilization in the region.

Reply to Query 13

The information has been added according to the reviewer´s recommendations (Line 105-107).

 

Reviewer´s Query 14

Clearly stating the study's objective enhances clarity. Provide a brief rationale for selecting xylanase, cellulase, and pectinase as the target enzymes.

Reply to Query 14

The information has been added according to the reviewer´s recommendations (Line 122-124.

 

Reviewer´s Query 15

The mention of scaling up the solid-state fermentation process is crucial. Introduce a sentence briefly summarizing the benefits of solid-state fermentation in comparison to other techniques.

Reply to Query 15

The information has been added according to the reviewer´s recommendations (Line 100-102).

 

Reviewer´s Query 16

Naming specific substrates (BSG and AP) provides specificity. Include a sentence explaining why these particular substrates were chosen.

Reply to Query 16

The information is presented in line 108-110

 

Reviewer´s Query 17

Introducing a packed column-type bioreactor with sensors is a key detail. Briefly explain the advantages of using a packed column-type bioreactor for large-scale production.

Reply to Query 17

The information has been added according to the reviewer´s recommendations (Line 126-129).

 

Reviewer´s Query 18

Discussing the economic feasibility adds a practical dimension. Provide a sentence on the potential economic implications for the region or industry.

Reply to Query 18

The importance of evaluating the technical and economic aspects of biowaste valorization through bioprocessing was emphasized (Line 72-77 and 95-97).

 

Section (2.Methods) :

Reviewer´s Query 1

Raw Materials and Inoculum Preparation: Clear description of the raw materials (AP and BSG) and their preparation. Mention the quantities of AP and BSG used for the experiments for better understanding.

Reply to Query 2

The additional information was added in line 138-140. The information about quantities is presented in section 2.4.

 

Reviewer´s Query 2

Microorganism Selection: The choice of Aspergillus sp. for solid-state fermentation is explained. Provide a brief rationale for selecting Aspergillus sp., emphasizing its suitability for the intended enzymatic production.

Reply to Query 2

The information has been added according to the reviewer´s recommendations (Line 141-143).

 

Reviewer´s Query 3

Bioreactor Design: The description of the packed-bed column bioreactor is thorough. Consider briefly explaining why a packed-bed column was chosen and its advantages over other bioreactor types.

Reply to Query 3

The information has been added according to the reviewer´s recommendations (Line 149-150).

 

Reviewer´s Query 4

Bioreactor Instrumentation: Detailed information on sensors used for monitoring CO2, humidity, and temperature. Provide a brief justification for the choice of these specific sensors and their relevance to the fermentation process.

Reply to Query 4

The information has been added according to the reviewer´s recommendations (Line 164)

 

Reviewer´s Query 5

Cultivation Conditions: Clear details on the optimized process conditions for enzyme production. Consider briefly discussing the significance of the chosen conditions in enhancing xylanase synthesis.

Reply to Query 5

The parameters were selected by statistical analysis and subsequently optimized. This is described in the work cited above. The selection of the xylanase conditions was due to the fact that the maximum production of each enzyme presented very different values of the evaluated parameters. With the xylanase conditions, cellulase and pectinase activities were obtained while other scenarios did not offer high activity. The reference was added to the introduction and materials and methods section.

 

Reviewer´s Query 6

Enzyme Recovery and Quantification: Well-explained steps for enzymatic extract recovery and quantification. Include a sentence discussing the importance of the chosen substrates (pectin, xylan, cellulose) in assessing enzyme activities.

Reply to Query 6

Enzyme activity can be measured using specific substrates, implying significance. By using specific substrates, we can gain valuable insights into overall enzyme activity.

 

Reviewer´s Query 7

Simulation Description: Comprehensive information on the simulation process and software used. Briefly mention why SuperPro Designer 10.3® was chosen for the techno-economic assessment.

Reply to Query 7

The information has been added according to the reviewer´s recommendations (Line 241-243).

 

Reviewer´s Query 8

Scenario Comparison: Clear delineation of three scenarios and their specific conditions. Include a sentence discussing the rationale behind choosing different scenarios and how they represent distinct optimization goals.

Reply to Query 8

The information has been added according to the reviewer´s recommendations (Line 254-257).

 

Reviewer´s Query 9

Techno-Economic Assessment: Well-detailed information on economic evaluation metrics and input parameters. Consider briefly discussing the expected impact of regional factors on the economic viability of the project.

Reply to Query 9

The economic indexes, along with their detailed analysis, have been thoroughly addressed and presented in the results section. However, it is important to note that the anticipated impact of regional factors on the economic viability of the project falls outside the scope of our current analysis. Our focus has primarily been on the internal economic metrics and parameters directly related to the project, and a detailed examination of regional influences is not within the purview of this study.

 

Reviewer´s Query 10

Sensitivity Analysis: Comprehensive exploration of sensitivity analyses variables. Include a sentence discussing the significance of each variable and how it might impact the overall process profitability.

Reply to Query 10

We appreciate the thoughtful consideration provided by the reviewer regarding sensitivity analysis. It is worth noting that, a comprehensive analysis of sensitivity variables, particularly focusing on how each raw material cost influences process profitability, was elaborated in the results section.

Section (3. Results) :

Your study provides a comprehensive investigation into enzyme production through fermentation using agro-industrial waste. Here are some comments and suggestions to enhance clarity and understanding:

 

Reviewer´s Query 1

Add a brief introduction before delving into the results, succinctly describing the study's objective and the context of enzyme production from agro-industrial waste.

Reply to Query 1

The information has been added according to the reviewer´s recommendations (Line 347-349)

 

Reviewer´s Query 2

Clarify the meaning of the values X, P, and C. Perhaps, mention the types of enzymes or compounds they represent.

Reply to Query 2

The description was improved (Line 351-352)

 

Reviewer´s Query 3

Specify at the beginning of the section the overall context of the enzyme market and why xylanases, pectinases, and cellulases are particularly studied.

Reply to Query 3

This information was previously included in the introduction.

 

Reviewer´s Query 4

In the section on sensitivity analysis, ensure to include appropriate units of measurement for costs and prices.

Reply to Query 4

As indicated in the article, the selling price of enzymatic extracts and the cost of commercially available enzymes can exhibit significant variability, and there is no universally agreed-upon selling price. Therefore, we have chosen to express these values in USD per enzymatic activity unit to account for this variability and provide a meaningful basis for comparison.

Reviewer´s Query 5

Add a conclusions section summarizing the key findings of the study, highlighting implications, and providing recommendations.

Reply to Query 5

Recommendations to further advance the bioproduction of enzymes within a biorefinery concept was included. (Line 615-622)

 

Reviewer´s Query 6

Carefully proofread the text to correct any grammar, punctuation, or style errors.

Reply to Query 6

We apologize for any formatting errors and thank you for bringing them to our attention. The text has been thoroughly revised.

 

Reference:

Reviewer´s Query 1

I noticed that the number of provided references (24) might benefit from expansion. For a work as interesting as yours, including additional references could further strengthen the robustness and credibility of your arguments.

Reply to Query 1

Recommendation appreciated; references added to support the information.

Reviewer´s Query 2

I suggest considering the addition of relevant references that could enhance your discussion and shed light on specific aspects of your research.

Reply to Query 2

Recommendation appreciated; references added to support the information.

Reviewer 3 Report

Comments and Suggestions for Authors

 

I examined thoroughly the manuscript Ref. No sustainability-2776722 entitled “Sustainable Co-Production of Xylanase, Cellulase, and Pectinase via Agroindustrial Residues Valorization through Solid State Fermentation: A Techno-Economic Assessment”.

A Major Revision is necessary at this stage to improve the scientific value of the paper.

Comments are listed in the following.

 

Comments   

·         All abbreviations should be defined upon first emergence within text.

·         English is not fluent and should be improved. Also, there are some grammar and misspelling errors throughout the text which should be thoroughly checked and corrected.

·         Literature review is not exhaustive. All related original/review papers should be exhaustively reviewed in the introduction section, then the novelty of the current work over previously published literatures should be highlighted.

·         Please indicate detailed full specification for each material and instrument used in EXPERIMENTAL section.

·         How is the reproducibility of the process investigated? How many tests for each sample have been done? Please add error bars for all figures and SD (standard deviation) values for all data.

·         Discussion on the results is poor. Several sentences in discussion section are obscure. Please avoid using unclear statements/sentences/explanations. Logical and scientific justification/explanation should be given for data/phenomena citing related literatures.

·         Scaling up of this process for industrial applications?

Comments on the Quality of English Language

 

English is not fluent and should be improved. Also, there are some grammar and misspelling errors throughout the text which should be thoroughly checked and corrected.

Author Response

General comments to Reviewer 3

We highly appreciate the constructive comments of all reviewers. We apologize for the obvious format mistakes, and we thank you for noticing them. We have addressed every suggestion made. We revise the manuscript thoroughly and improved the writing. The new text additions and the revised sections are highlighted using the Word tracking changes option. We numbered each query and made changes in the text to answer all the suggested queries. The explanation provided next refers to the updated line numbers.

Comments to the authors: I examined thoroughly the manuscript Ref. No sustainability-2776722 entitled “Sustainable Co-Production of Xylanase, Cellulase, and Pectinase via Agroindustrial Residues Valorization through Solid State Fermentation: A Techno-Economic Assessment”.

A Major Revision is necessary at this stage to improve the scientific value of the paper. Comments are listed in the following.

Reviewer´s Query 1

All abbreviations should be defined upon first emergence within text.

Reply to Query 1

The abbreviations have been revised.

 

Reviewer´s Query 2

English is not fluent and should be improved. Also, there are some grammar and misspelling errors throughout the text which should be thoroughly checked and corrected.

Reply to Query 2

The text was proofread to improve readability and text flow.

 

Reviewer´s Query 3

Literature review is not exhaustive. All related original/review papers should be exhaustively reviewed in the introduction section, then the novelty of the current work over previously published literatures should be highlighted.

 

Reply to Query 3

Thanks for the recommendation. The literature review was extended, and the introduction was rewritten to incorporate more details and accommodate reviewers' recommendations.

 

Reviewer´s Query 4

Please indicate detailed full specification for each material and instrument used in EXPERIMENTAL section.

Reply to Query 4

Details were added to the materials and methods sections.

 

Reviewer´s Query 5

How is the reproducibility of the process investigated? How many tests for each sample have been done? Please add error bars for all figures and SD (standard deviation) values for all data.

Reply to Query 5

Thank you for your thoughtful consideration of our study, and we appreciate your feedback on the reproducibility of our process. We conducted the process multiple times to ensure consistency; however, we acknowledge the absence of error bars in our figures and standard deviation (SD) values in the reported data.

 

In response to your recommendation, we understand the importance of enhancing the transparency and completeness of our findings. It is important to note that due to the primary focus on demonstrating sensor performance and resource constraints, detailed testing for each sample was not conducted as extensively as we would have preferred. Deviation data is included only for the results in enzymatic extracts activity.

 

Nevertheless, we believe that the results still provide valuable insights, particularly highlighting the necessity of early economic process evaluation and the information that can be derived through process simulation. We appreciate your understanding of the constraints we faced and are committed to presenting a comprehensive and transparent account of our research in the revised manuscript.

 

Reviewer´s Query 6

Discussion on the results is poor. Several sentences in discussion section are obscure. Please avoid using unclear statements/sentences/explanations. Logical and scientific justification/explanation should be given for data/phenomena citing related literatures.

Reply to Query 6

While we acknowledge your concerns about clarity and logical justification, our choice to prioritize economic discussions is intentional, aligning with the overarching objectives of guiding future research efforts. For instance, the process simulation aids in identifying areas for improvement, such as the influence of inoculum medium costs. This analysis demonstrated that opting for a cost-effective medium, could substantially enhance ROI, especially with increasing batch size.

Additionally, our results highlight the significant impact of changes in enzyme prices, particularly xylanase, on process profitability. We highlighted the importance of price stability and competitive pricing in the enzyme market.

 

Reviewer´s Query 7

Scaling up of this process for industrial applications?

Reply to Query 7

A conclusion statement was added regarding the need for scaling-up the process.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors did a great job. They took into account almost all my comments. The question about the composition of the substrates used in the Methodological Part remained unclear. At least the cellulose-xylan ratio is required.
The whole text of the article should be carefully checked. For example, duplication of the titles of sections 2.5 and 2.6.

Author Response

Comments to the authors

The authors did a great job. They took into account almost all my comments. The question about the composition of the substrates used in the Methodological Part remained unclear. At least the cellulose-xylan ratio is required.

The whole text of the article should be carefully checked. For example, duplication of the titles of sections 2.5 and 2.6.

 

General comments to Reviewer 1

The authors are grateful for the reviewer's comments, as the corrections made to the information presented made it more meaningful. The text was further revised and improvements were made to the English language. The title of section 2.6 was corrected. As for the composition information requested by the reviewer, this was added in the results (Line 332-340).

Reviewer 2 Report

Comments and Suggestions for Authors

 Accept in present form

Author Response

Comments to the authors

Accept in present form

Reviewer 3 Report

Comments and Suggestions for Authors

 

I examined the revised version of manuscript Ref. No sustainability-2776722 entitled “Sustainable Co-Production of Xylanase, Cellulase, and Pectinase via Agroindustrial Residues Valorization through Solid State Fermentation: A Techno-Economic Assessment”.

The correction made by authors have improved the scientific value and quality of paper and now in my view it is acceptable for publication.

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Comments to the authors

I examined the revised version of manuscript Ref. No sustainability-2776722 entitled “Sustainable Co-Production of Xylanase, Cellulase, and Pectinase via Agroindustrial Residues Valorization through Solid State Fermentation: A Techno-Economic Assessment”.

The correction made by authors have improved the scientific value and quality of paper and now in my view it is acceptable for publication.

 

Comments to the reviewer

The authors are grateful for the comments made to improve the quality of the article.