Hydrogen Production from Sugarcane Bagasse Pentose Liquor Fermentation Using Different Food/Microorganism and Carbon/Nitrogen Ratios under Mesophilic and Thermophilic Conditions

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

 

I revised the manuscript “Hydrogen Production from Sugarcane Bagasse Pentose Liquor Fermentation Using Different Food/Microorganism and Carbon/Nitrogen Ratios under Mesophilic and Thermophilic Conditions” submitted to the Fermentation Journal. In this article, the authors discuss the important problem of hydrogen production during dark fermentation (mesophilic and thermophilic) of waste (sugarcane bagasse pentose liquor) from the production of bioethanol from sugarcane bagasse.   

I have a few comments that need to be corrected before the eventual publication of the article.

 

1. Introduction 

Line 42-43. Please give an example along with fossil fuel energy in the introduction.

 

3. Results

Figures 1, 2 and 3 and Table 1 are illegible, making it impossible for the reviewer to check and refer to the discussion and the authors' findings. Please improve the legibility of the figures.   

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The abstract should include the numerical results, the hydrogen yields, the volumetric velocities, as well as the value of the F/M and C/N ratios that were tested. The study needs to be improved especially in the way it presents and discusses the results.

Abstract: What were the pre-treatment conditions? Were the levels of furan derivatives, phenols, acids measured?

Please rewrite the following idea: The main VFA produced was acetate and butyrate pathway was the most common metabolic route of experimental essays.

Lines 53-59, it would be useful to refer to works that have aimed at a systematic comparison of dark fermentation systems in mesophilia and thermophilia, as well as the main conclusions obtained.

 "it gives a final destination for hard-degradation residues that have no clear safe disposal" Dark fermentation is not considered a waste treatment technology per se.

Line 76, under what conditions were these studies conducted, were they studies designed to evaluate C/N ratio, F/M? what type of substrates were evaluated.

Line 99: Can you provide more data on the substrate used in this study, production volume, production ratio in terms of bioethanol produced, physicochemical characteristics? Are there other studies that have used this liquor for fermentative hydrogen production? If so, what were the main advances?

Rewrite lines 103-105 being more concrete and clear.

What was the justification for testing and setting the F/M ratio first?

Results:

Report the duration of the culture in days.

Line 229: Values are missing.

Both hydrogen productivity and hydrogen production volume should be referenced or normalized to liter of reactor (volumetric).

Keep the use of abbreviations to a minimum; it is difficult to follow the results with so many acronyms.

The quality of the figures should be improved. The text is illegible.

 

Comments on the Quality of English Language

The manuscript is well written with respect to English, it is suggested to revise some typos throughout the document.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

I have revisited the manuscript “Hydrogen Production from Sugarcane Bagasse Pentose Liquor Fermentation Using Different Food/Microorganism and Carbon/Nitrogen Ratios under Mesophilic and Thermophilic Conditions” submitted to the Fermentation Journal. The work has been improved according to my recommendations. The article is fully suitable for publication in Fermentation Journal.