Review Reports

Round 1

Reviewer 1 Report

This work investigates Sargassum muticum with regard to its anaerobic digestion performance in different BMP test systems. Results evidenced that co-digestion of SM with wheat straw has positive effects on SBY and SMY.

The work is appropriate for readers and interested in Fermentation journal. The objective or problem defined by the authors is clear with valuable experimental development, but it is necessary to include statistical criteria.

All results have statistical support, which is rare in this type of work. This shows the authors' concern with the published result.

Minor points in the article which need clarification, refinement, reanalysis, rewrites, and/or additional information are described below.

 

1.     The title of the work is informative and relevant, highlighting the purpose and the subsequent comparison using different biomasses. Nevertheless, authors must reduce to 100 characters.

 

2.     On the other hand, the references presented in the manuscript are relevant, but not recent. References need to be included correctly following the layout and format of the journal. Please consult the author's guide. Some studies are highlighted in the specific comments to contribute to the discussion and comparison of the results with investigations reported by other researchers.

Author Response

The authors would like to thank the reviewer for time and efforts as well as suggestions to improve our manuscript. We hereby deliver an improved version of our paper that was generated based on the reviewer’s comments.

 

1. Comment:

• We shortened and slightly modified the title. The new title of the manuscript is “Impact of thermo-mechanical pretreatment of Sargassum muticum on anaerobic co-digestion with wheat straw”. This title equals approx. 100 characters.

 

2. Comment:

• Thank you for the remark. We added further, more recent references to the paper and we modified our reference section to bring them in accordance with the MDPI Fermentation guidelines.
  • Additional references
    • Dandikas et al. (2021) was implemented for further information on SMY of energy crops
    • Grillo et al. (2021), Silva et al. (2021) and Rocha et al. (2021) was implemented for presenting further utilization approaches that are currently discussed with Sargassum muticum (this discussion is linked with the introduction topcis, see comment of reviewer 2)
    • Caxiano et al. (2022) was implemented to provide information about economical aspects of muticum in anaerobic digestion.
    • Leong; Chang (2022) was implemented to show the possibility of integrating muticum in a closed-loop circular economy
    • Maneein et al. (2021) was implemented to give an example for other studies, that resulted in relatively low specific methane yields of muticum during anaerobic digestion.
    • Rivera-Hernández et. al (2022) was implemented to give information about positive effects of co-digestion of muticum.
• We updated the Reference section (please see the whole reference section) and provided further information on several references.

Reviewer 2 Report

This article is very well-written and has clear objectives

1. While the introduction covers several relevant aspects, there might be an opportunity to further organize and transition between different sections for smoother flow and coherence.

2. I recommend that the authors elucidate, in concise terms, the economic viability of the proposed method through a comparative analysis of the overall costs. Kindly provide a succinct assessment of the method's economic feasibility by considering the comprehensive expenditure involved.

very minor correction in English is required, you can use the free program grammarly.com to detect the errors.

es. line 41 fossil resources as well as on certain states is problematic should be are problematic

line 48 The renewable should be renewable

line 58 aAthreat for ecosystems should be a threat to ecosystems

line 61

 

etc…….

Excellent article that should be accepted after a very minor correction

Author Response

First of all, we would like to thank the reviewer for time and efforts to read and improve our manuscript. Further, we thank for the positive feedback. We improved our manuscript in accordance with the reviewer’s feedback. Further explanations are given below. All changes that were made in the manuscript are highlighted in yellow. 

Comment 1:

• Some relations in text flow have been adjusted to improve coherence. Changes have been highlighted in the manuscript. Please kindly see the whole manuscript.

Further Changes:

• Minor corrections in English have been applied and highlighted in the manuscript, inter alia:
  • “fibre” (BE) has been replaced by “fiber” (AE) and “analyse” (BE) has been replaced by “analyze” for consistency in American English (entire manuscript)
  • Often unnecessary use of the word “the” has been reduced (entire manuscript)
• Correction in Conclusion line 638: correction of SMY of maize silage and rapeseed as we unfortunately first mentioned SBY instead of SMY.
  • Nevertheless, the determined SMY of S. muticum (approx. 100 L/kgVS) remains relatively low compared to other biogas substrates such as maize silage or rapeseed (both typically between 300-400 L/kgVS … (line 637-638)

Comment 2:

• Thank you for your suggestion. We agree that it is important to evaluate the economic feasibility of our methods and or approach. Unfortunately, we do not have any detailed data on expenditures. Therefore, a new paragraph on economic viability has been inserted at the end of the results & discussion but with general statements. We also pointed out that this could be a field of further research. We also added information on the economic assessment in the conclusion section.
  • Another aspect is to assess the overall economic viability, which includes several as-pects. For instance, … Still, further research for now should focus on cost-efficient but more effective pretreatment or digestion methods of Sargassum spp. to increase SMY. (line 607-627)
  • Nevertheless, feasibility studies to evaluate benefits and expenditures caused by the substrate pretreatment should complement the results of this work. (line 646-647)