Methane Production Reduced by Lignin Derivatives in Pulping Wastewater: Inhibition of Free Hydrolase
, Jian Zhang 1,2,3,*, Kelin Li 1 and Li Xie 1
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper Methanogenic activity depression by lignin derivatives in pulping wastewater: inactivation of free hydrolase is interesting, but the title of the manuscript is misleading. As a reviewer I didn’t see where in the manuscript this pulping wastewater was discussed (there is only discussion and results regarding artificial wastewater) and hydrolase enzymes are not discussed. There is more discussion and results regarding flocculation, substrate aggregation and methanogenic activity. The language is very hard to follow, there are certain phrases that are strange, or some words are used that are not appropriate. Also, activity depression is not a phrase that is used in such kind of manuscripts.
My other remarks are as follows:
Line 14: What is HA? If some abbreviation is used for a first time then it must be described in full. What are HAs group?
Line 17: What Are experiments on enzyme activities? Determination of an enzyme activity? It is not plural
Line 25: What are granular sludge bed reactors of pulping wastewater? This looks like combination of a few terms and it looks that author cannot distinguish what are proper terms to use in such example. “Bed reactors” can be fixed, fluidised, tubular, packed, trickle… Please specify what kind of reactor it is. Granular sludge is activated or inactive? Is this the biomass? The substrate? Is the pulping wastewater the wastewater from paper and pulp industry?
Line 29: Plant as factory or plant as in biological plant (wood for example)?
Line 33: You are discussing lignin and separation of lignin and problems with lignin, but there is no lignin mentioned in your paper.
Line 48: What are wood extractives? This is unclear
Line 51 – 52: This sentence is poorly written and unclear. It should be rewritten.
Line 54: What do you mean by acidity? Maybe acidification is proper term that has more meaning?
Line 57: An enzyme. Please check your grammar
Line 61: The term “morphology associated with enzymes” is unclear and should be written in proper and clear manner
Line 68-69: What is importance of this sentences? Is this relevant to your paper?
Line 74 - 75: This part is poorly written. “enzyme shape” do you mean that this biding is or can change the shape of an enzyme? What enzymes? Does this change influence the activity?
Line 81 – 84: The source of Ca2+ is calcium. I presume what you want to say but this is poorly written
Line 100: What is acidity level of 50%?
Line 124: Why is this important and added to your HAs group?
Line 130: What is specimen blending?
Line 152: What is substrate status?
Line 203: Please discuss this importance of humic acid
Line 213-2014: Bacteria in extracellular region? Bacteria are cells, and therefore I cannot understand what is extracellular in your case? Did you mean enzymes? Because they can be either extra or intracellular or even adhered on a cell.
Line 218: hindered as inhibited? Or reduced activity?
Line 225: Maybe is the formatting or some error, but there is no title of your table or description
Figure 1 and 3. Please correct the figures. You are writing STRACH instead of Starch
Line 254 and 292: Do not use the term Repulsive or Repulsive forces
Line 361- 362: I cannot understand this sentence, please elaborate this statement
Comments on the Quality of English LanguageLanguage needs thorough check
The manuscript is hard to follow because of that
Lot of sentences are poorly written and some words that are used are not appropriate
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe manuscript, "Methanogenic activity depression by lignin derivatives in pulping wastewater: inactivation of free hydrolase," investigates how lignin derivatives, particularly humic acids (HAs), affect anaerobic granular sludge in treating pulping wastewater. It reveals that HAs hinder the conversion of substrates into methane by inhibiting enzyme activity and weakening sludge cohesion, consequently reducing biomass in reactors. This study underscores the long-term risks associated with using granular sludge bed reactors for pulping wastewater treatment.
Some comments are provided:
The abstract should conclude instead of providing a summary of the results.
Abbreviations such as "HAs" should be defined before use.
Chemical formatting standards should be adhered to, such as capitalizing ions like Ca+2 throughout the text.
All ideas should be referenced, as seen in lines 57-67.
Basic grammar editing is needed, such as "En enzymes" in line 57; ".2 Materials and methods" in line 92; ".2 Materials and methods" in line 92; "through a 0.45 m PES membrane" in line 156; open parentheses in line 159, 217, 263; "Figs" in line 209; a degree symbol instead of a period in line 292; redundant writing in line 192: "in units of U/mL."; an incomplete idea in lines 196-197: "One unit of enzyme activity (nmol/min/gVSS) was phenol." ...phenol what?
The idea in lines 213-214 should be clarified: "Bacteria responsible for hydrolysis and their metabolic activities are primarily found in the extracellular region [21]." How can bacteria be found in the extracellular region? Are there bacteria in the intracellular region?
The basic scheme for scientific communication, including the difference between results description and discussion, should be understood.
Comparison and relation of findings with those reported in the literature with similar works should be made.
A conclusion should be provided.
Methods should include enough detail for reproducibility, including supporting references, equipment conditions, and manufacturer details, such as COD standard techniques, laser particle size, modified Folin–Lorrow method, polysaccharide using anthrone-sulfuric acid, zeta potentials, median diameter(D50), etc.
The meaning of an acidity level of 50% in line 100, the composition and preparation of simulated wastewater, and 1 PBS buffer solution should be detailed.
In section 2.4, clarification and justification for obtaining two extracts and their significance "LB-EPS and TB-EPS" should be provided.
A descriptive title for the table, including appropriate units for the data, should be included.
A description of the statistical analysis of the data should be provided.
The reason for referencing the results obtained in this study should be explained: "This observation agrees with the alteration in sludge zeta potential reported in Section 3.2.1 [31-33]."
The manuscript should comply with basic standards for scientific communication, recognizing and respecting the time invested in reviewing it.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsAuthors have addressed the majority of remarks and reviewers suggestions
Comments on the Quality of English LanguageAuthors have addressed the majority of remarks and reviewers suggestions regarding language
Author Response
我们更正了文章中因粗心大意而出现的错误，并优化了语法和语言呈现。衷心感谢您在本论文评审过程中的宝贵意见，使我的文章的逻辑和质量有了显著的提高。
Reviewer 2 Report
Comments and Suggestions for AuthorsIn this revised version of the manuscript, the authors have addressed some of the comments. However, for further improvement, there are other comments to consider.
In lines 49-50, the authors should include a pair of references "Although a few studies have demonstrated that lignin," as they do in line 360. As well as, in lines 55-57, 258-259.
The authors should improve their writing, as seen in lines 213, 214, and 235-236: "2.8.2 α-glucosidase," "The enzymatic," "formulation of acetic."
In Table 1, as well as in figures, the authors should include letters or symbols indicating statistical differences between treatments.
In lines 278-285, the authors should relate their data and findings to the fundamentals. They should discuss the fundamentals proposed by Xu et al. [42] and [43] with their data, and so on. Additionally, the authors should properly discuss and relate the fundamentals to their findings, as they do in some other results, such as in lines 313-319 and section 3.3 Assessment of potential impacts on microbial aggregation.
In lines 294-295, the authors should discuss the reasons or the fundamentals supporting "This, in turn, enhanced the efficacy of centrifugation in eliminating casein from the HA–Ca group."
In Figure 6, the authors should adjust the scale of the "y" axis for better observation of the data.
The authors must draft the conclusion in prose, removing the numbering. Additionally, they should include the possible application of the generated knowledge and generate ideas in a proactive sense, stating what can be done rather than what cannot be done.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
