Modeling of 1,2-Dibromoethane Biodegradation in Constant Electric Field
Chao Zhu
Round 1
Reviewer 1 Report
This study describes the biodegradation behavior and kinetic characteristics of magnetic field-enhanced organic pollutants, which is instructive with an obvious promotion on the degradation rate and an possible explanation on the mechanism, but related work has been reported, and this study is not innovative enough based on the past work. The main issues are as follows:
1. The measurement index and data form of the article are relatively simple, only the data of pollutant concentration and microbial growth rate, lacking the data of relevant environmental factors, and the unclear boundary of the model somehow limits the use of the model.
2. The lack of data on the degradation intermediate of 1,2-DIBROMOETHANE does not support one of the objectives of this study, i.e., whether the pathway of enhanced biodegradation by magnetic field is to reduce the negative feedback inhibition of the products by enhancing the secondary conversion rate of the pollutants into biological metabolites or to directly stimulate microbial growth, which is still not clearly explained by this study.
3. The introduction lacks research development on the microbiological effects of magnetic fields and the mechanisms associated with enhanced biodegradation.
Author Response
We are grateful to the reviewer for his useful remarks.
This study describes the biodegradation behavior and kinetic characteristics of magnetic field-enhanced organic pollutants, which is instructive with an obvious promotion on the degradation rate and an possible explanation on the mechanism, but related work has been reported, and this study is not innovative enough based on the past work. The main issues are as follows:
- The measurement index and data form of the article are relatively simple, only the data of pollutant concentration and microbial growth rate, lacking the data of relevant environmental factors, and the unclear boundary of the model somehow limits the use of the model.
Answer: The studied effect is of constant ELECTRIC field, not a magnetic one. The limitations of the experiments and the model application are associated with the substrate and the used bacteria. In the present case the “environmental” conditions are described in the section 2.1 Bacterial strain, media and experimental conditions. I don’t understand what does the reviewer mean in “unclear boundary of the model”. The model describes batch process with reactions running in time.It is suitable for the studied process, as shown by the obtained parameter values and the least squares sums.
- The lack of data on the degradation intermediate of 1,2-DIBROMOETHANE does not support one of the objectives of this study, i.e., whether the pathway of enhanced biodegradation by magnetic field is to reduce the negative feedback inhibition of the products by enhancing the secondary conversion rate of the pollutants into biological metabolites or to directly stimulate microbial growth, which is still not clearly explained by this study.
Answer: additional figure and text are added in a new paragraph 3.1. to demonstrate the effect of the ELECTRIC field on the product formation and depletion together with the asociated bromide release in the broth. The reduction of the negative feed-back of the product on the microbial growth is demonstrated in Tables 2 and 3. Both effects are demonstrated and discussed: microbial growth enhancement and secondary electrochemical oxidation to remove the inhibitor.
- The introduction lacks research development on the microbiological effects of magnetic fields and the mechanisms associated with enhanced biodegradation.
Answer: The known research on this process was made by our team and it is cited and used in this paper. The introduction is re-written and edited, where the possible mechanisms of the impact of constant ELECTRIC field on the studied process are noted.
Reviewer 2 Report
Main question addressed by the research: The work addresses the modelling of dibromoethane biodegradation in constant electric field.
Originality and relevance of the topic: The topic is relevant to the field and it considers a suitable model (research gap).
Added value of the paper: The manuscript takes into account the study and assessment of the mechanism with parametric analysis, however the paper should include what aspects are critical for these assessments and clearly explain why they are analysing those and why they are needed at the end of the Introduction.
Quality of figures: Good and easy to follow.
Specific improvements for the paper to be considered:
- I think they have covered all the aspects required for the results, however the validation of the results is not clearly explained and this is essential in order to justify the reliability of the results.
- Abstract is too short and general. It should summarize the main findings and applications of the paper.
- The selection of the optimal catalytic conditions is unclear. What is the best option for the biodegradation? Final statement from main findings is not clearly explained.
- The conclusions are poor and they would need more elaboration so they clearly match the results.
Author Response
We are thankful to the reviewer for his useful suggestions.
Main question addressed by the research: The work addresses the modelling of dibromoethane biodegradation in constant electric field.
Originality and relevance of the topic: The topic is relevant to the field and it considers a suitable model (research gap).
Added value of the paper: The manuscript takes into account the study and assessment of the mechanism with parametric analysis, however the paper should inc lude what aspects are critical for these assessments and clearly explain why they are analysing those and why they are needed at the end of the Introduction.
Quality of figures: Good and easy to follow.
Specific improvements for the paper to be considered:
- I think they have covered all the aspects required for the results, however the validation of the results is not clearly explained and this is essential in order to justify the reliability of the results.
Answer: the validation of the results is evident from the values of the sums of the squares. They corresponds to standard deviation of less than 0.003 g dm-3. The measured concentrations are 0.05-0.1 g dm-3.
2. Abstract is too short and general. It should summarize the main findings and applications of the paper.
Answer: abstract is completely re-written in the sense suggested by the reviewer. It fits the conclusions.
3. The selection of the optimal catalytic conditions is unclear. What is the best option for the biodegradation? Final statement from main findings is not clearly explained.
Answer: new text, describing why these experimental conditions were selected (e.g. the chosen anode potential) is added. The main findings are formulated in the abstract and in the conclusions.
4. The conclusions are poor and they would need more elaboration so they clearly match the results.
Answer: the conclusions are re-written and include the main findings of the modelling.
Round 2
Reviewer 2 Report
The paper has significantly improved and it should be published.
