Combined Transcriptome and Metabolome Analysis of a New Species of Microalgae from the Tibetan Plateau and Its Response to Sewage Treatment

Round 1

Reviewer 1 Report

Dear authors,

Your study describes the response of the microalga Desmodesmus sp. to sewage treatment based on a combined transcriptome and metabolome analysis. Although the topic of the manuscript is interesting and relevant, the manuscript presents a series of major flaws. The manuscript is written in a very confusing way, it is very hard to follow what you did, it needs more structure and precisions in all the sections. The introduction is too short and does not give the proper context to the reader, the methods need more details such as the composition of the synthetic wastewater and the techniques used to analyze the different parameters evaluated, among others. Error bars in the figures are missed and letters from figures 3 and 5 are very small to read on a printed version. Additionally, the text in methods and results is very repetitive and tedious to read, a thoroughtful English edition is needed. In sum, the manuscript should be improved significantly before being considered for publication.  

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

It is well known that microalgae play a key role in maintaining water quality in lakes and rivers. The manuscript concerns a well-known species of Desmodesmus sp., which was the use of which in ecological wastewater treatment technology gives excellent results. It should be noted that the authors obtained the maximum removal rate of total nitrogen, total phosphorus, and chemical oxygen demand more than 95% in the actual sewage treatment. The study used a combination of two methods: metabolomics and transcriptomics for microalgae involved in wastewater treatment and without treatment. The wastewater treatment process has been shown to alter primary metabolism, including carbohydrate, fatty acid biosynthesis, and amino acid metabolism compared to control. The results are very interesting and constitute the basis for the development of technology for the use of Desmodesmus sp microalgae in wastewater treatment.

The study showed that the most efficient treatment of COD, TP, and TN was on the third day, and the efficiency was  more than 95.0%. An important issue that the authors dealt with was to optimized and determined the optimal treatment conditions of Desmodesmus sp. for sewage treatment, and the specific treatment conditions.  The results obtained in the study significantly broaden the knowledge of responses at the molecular level of Desmodesmus sp. during wastewater treatment and will significantly influence for the development of modern technology.

-The work has been carefully written and the developed results are presented in a clear and reliable manner.

- Is in Figure 1…… (b) TP treatment trends under different pH Conditions; should be: (b) TP treatment trends under  different pH conditions;

- The authors may consider supplementing the literature in the thematic scope with the following items:

M. Dębowski, P. Rusanowska, M. Zieliński, M. Dudek and Z. Romanowska-Duda  2018. Biomass Production and Nutrient Removal by Chlorella vulgaris from Anaerobic Digestion Effluents. Energies 2018, 11, 1654; doi:10.3390/en11071654.

Agata Pszczółkowska, Wiktor Pszczółkowski, Zdzisława Romanowska-Duda 2019. Potential of Chlorella vulgaris culture for waste treatment from anaerobic biomass biodigestion at the Piaszczyna (Poland) integrated facility. Journal of Phycology, vol. 55, no 4: 816-829; DOI: 10.1111/jpy.12856

Kisielewska M., Zieliński M., Dębowski M., Kazimierowicz J., Romanowska-Duda Z., Dudek M. 2020.  Effectiveness of Scenedesmus sp. biomass grow and nutrients removal from liquid phase of digestates. Energies 13(6), 1432;   https://doi.org/10.3390/en13061432

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

In the paper by Jinhu et al. entitled “Combined transcriptome and metabolome analysis of a new species of microalgae from Tibetan plateau and its response to sewage treatment”, the authors proposed the use of the green microalgae Desmodesmus sp. for wastewater treatment. The authors indicated the best conditions of treatment efficiency, in terms of pH; light intensity and temperature also comparing Desmodesmus sp. obtained from plateau and plains. Finally, authors analysed the transcriptome and the metabolome obtained from the microalgae used in sewage treatment.

The paper is interesting and well written. Title and Abstract are appropriate for the content of the text. Introduction needs to be improved and other references should be added. Please, give more information about Desmodesmus sp. Why do you use this microalgae species? Why do you use the microalgae isolated from Qinghai-Tibet Plauteau? The method section is transparent, however, no information about the methodology for COD, TN and TP measurement and RNA extraction are reported. The results are presented properly and they are discussed appropriately. The authors carefully designed and interpreted their experiments and made good use of statistics in the experimental design.

In addition, I have only few comments and recommendations.

Line 135: Flurometer.

Line 136: analyzer.

Line 137: qRT-PCR

Line 137: I suppose that the concentration was 2 nM and not 2nm

Line 153: Q30

Line 205: ..which were..

Line 210: …by cor ().

Line 212: ..was satisfied.. 

Author Response

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Author Response File: Author Response.docx