A Photosynthetic Bacterium Suitable for Treating High-Salinity Sea Cucumber Boiling Broth

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear Authors,

The manuscript is very interesting because it concerns the treatment of water contaminated by Sea cucumber boiling broth (SCBB), however it is necessary that you give some clarifications:

1- It has been indicated that the bacterium Marichromatium sp. DYYC01, isolated from Yan- 354 is able to reduce the COD content, however as indicated in Fig. 2 line 213, however the growth occurs in an anaerobic environment and therefore the potential use in the real field is not understood;

2- The possibility of using these microorganisms in the bioremediation of xenobiotic compounds (not only SCBB), which characterize the contaminated waters, has not been addressed;

3- A scaling-up that can really determine use in the bioremediation of contaminated waters has not been hypothesized (e.g. construction of bioreactors, immobilization of bacteria on solid matrices, etc.).

4- The bacterium Marichromatium sp. DYYC01 is indicated as interesting for the development of a circular bioeconomy (line 30), however the authors do not clarify the potential use of the biomass obtained. The authors therefore need to clarify these aspects.

Best regards

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript entitled "A Photosynthetic Bacterium Suitable for Treating High-salinity Sea Cucumber Boiling Broth" presents the results of a well organized and detailed experimental work to investigate the possible applications of photosynthetic bacterium regarding COD, P and N removal. At the same time the work involves the effect of light intensity and pH on the growth of the bacteria, two key factors involved in photosynthetic bacteria metabolism.

The background presented is pertinent and the area of application in biotechnology of this type of research is of current interest, particularly to produce valuable products and removal of organics in wwt. The justification and objectives of the work are clear and the experimental strategy is pertinent. However, there are a couple of main observations that the authors may want to consider regarding the presentation of the results.

1) For example, in figures 6 and 8, the authors refer to "removal rate" (for removal rate the units would be something like mg COD / L * h, mg N /L*h, or mg P/ L*h)) " when they are actually presenting percentage of removal (%), please make that correction in both, the text and the figures. In the same figures, panel a) "changes in TP, TN and COD" the legend should be corrected since the concentrations are shown instead. The correction could be something like "variations in the concentration of TP, TN and COD". Please make the correction in the figures and the text when required. 

2) In section 3.4 the authors present figures 3 and 4 which show optical densities to indicate biomass growth. In the text the authors refer to "biomass yield" instead. Biomass yield would have different units (i.e. mg biomass/ mg substrate) * 100 (if you want percentage). Please modify the text and legends of the figures accordingly. The legends of the figures must describe accurately what is presented, i.e., OD obtained for strain "XXXX" at different temperatures". It is known that OD represents different concentration of biomass. 

The findings reported in the document are overall very interesting and valuable for the biotechnology field. I would consider the document for publication after the observations that I just mentioned are considered by the authors since the results have to be presented correctly. 

Minor mistakes, for example, the blanks that are missing between the numbers and the units, a typo in line 148 and the utilization of the word "hours" instead of "h" can be easily corrected in the entire document. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript can be accepted for publication.