Interaction and Metabolic Function of Microbiota during Tibetan Tea Fermentation through Bioaugmentation with Aspergillus niger

Round 1

Reviewer 1 Report

Please find below some suggestions and comments:

-lines 7 to 17: Maybe harmonize email adresses (some are links, others not)

- line18 : rephrase the first sentence with a subject and a verb to present the background

-line 18, 30, 32: "nigers" => niger

-line 25: "NE" is not explained previously in the text

-line 28: "Blastobotrys" => B. 

-line 66: "the sensory quality of Pu-erh tea during" => the sensory quality of Pu-erh tea (a kind of dark tea)

-line 71: suppress  (a kind of dark tea)

- line 76: verb is missing

- line 91: "to analyze this scientific problem" => rephrase (e.g. lack of knowledge,...)

- line 102: "a fungal strain" => Aspergillus niger K1

-line 103-105: please add methodological details ( DNA sequencing but also the phylogenetic analysis) e.g. where come from other ITS sequences, which software did you use for alignment (MEGA? if yes, please add citation) and which method (maximum likelihood), bootstrap replications...

-line 109:  1x106 CFU/ml ? should not be spores/ml ? I don't think colony formant unit is appropriate for spores

-line 110 : "5 kg distilled water" => 5 kg sterile distilled water

- line111: "100 mL spores" => 100 mL spores solution

-line 113-114: make a sentence with subject and verb

-line 122-126: was the sensory evaluation a blind study ?

- line 154 -158: perhaps add this text in a specific part "Accession numbers" 

- line 163: I do not understand, OP603895 is the accession number of strain K1, so it should be in the text "was clustered with MK332597.1"

 -figure 1: "K1" should be placed after "OP603895.1 Aspergillus niger"

- Figure 2: Abbreviations WE, TP... should be explained in the legend to facilitate the observation of the figure

- Table1, Table2 => Table 1 Table 2

- bacterial OTU: it is very hard to be confident at the species level with 16S rDNA. It is for example not possible to determine the species among Pseudomonas genus only with 16S DNA; this is the case for many other bacterial genus. I would recommend in text and figures to write only bacterial genus

-line 262 and 272 : 12 superclasses, not subclasses

- line 274-310. indicate only major ones and lists all others as supplementary data

- Figure 7: Why Ralstonia insidiosa is not presented as other microorganisms ?

- complete the conclusion by highlighting key points of the study in regards to the literature without repeating results. For example regarding health promotion described in the introduction, are metabolites identified in BF related with health benefits in the litterature ?...

The quality of English language must be deeply improved. Some sentences are difficult to understand. If possible the manuscript should be read by an english native speaker. Please find below some suggestions:

- line 3:  Bioaugment => Bioaugmentation

-  line 22, 51: do not start a sentence with "And"

- line 41: "Tibetan tea also been reported" => Tibetan tea has also been reported

- line 45: "were" => are

-line 48: "are formed" => occur

-line 49: I do not understand the sentence

-line 63-64: "by inoculation of Clostridium [...]" => by inoculating Clostridium acetobutylicum and Shigella flexneri strains"

-line 80: "presented" => present

-line 81 'generated" => generate

-line 90: "of both scientific" => both of scientific

-line 107: "into" => onto ?

-line 147-148: rephrase

Table 1 "sensory evaluation of Tibetan tea from BF and NF" => Sensory evaluation of Tibetan tea with BF and NF 

- line 255: a word is missing

-line 333: "we result" => "our results"

Author Response

Please see the attachment.

Author Response File: Author Response.doc

Reviewer 2 Report

It is an interesting paper dealing with the sensory quality of Tibetan tea. The authors inoculated with Aspergillus nigers K1 tea leaves to develop bio augmented fermentation  and normal fermentation of Tibetan tea.The dominant bacterium of BF was Staphylococcus kloosii , while  Blastobotrys adeninivorans  was the dominant fungus. Yet, 859 metabolites were identified andalso  the level of 90 metabolites was increased in bio augmented fermentation  compared to normal fermentation. As a result,  Aspergillus nigers inoculation in tea leaves  for bio augmented fermentation can trasnsform the metabolites in tea by synergistic effect with other microorganisms, and improve the sensory quality of Tibetan tea.

It is a well written paper based on a heavy methodology (sequencing and metabolomic analysis) followed by sensory evaluation and characteristic compositions of the tea leaves. The authors studied also the influence of Aspergillus Niger K1 on tea microbiota and  analysis of correlation between microorganisms, characteristic compositions  and DCMs was done.

The study will be of great interest to the industrial world as well as to the scientists working on fermentation issues.

It is a scientifically sound paper well written and well designed with consistent results well discussed in depth.

Figures and other schematic representations are well prepared.

My suggestion is to ACCEPT and publish this paper in its present form.

Author Response

Dear Reviewer 2:

Thank you for your comments concerning our manuscript entitled “Interaction and Metabolic Function of Microbiota during Tibetan Tea Fermentation through Bioaugmentation with Aspergillus Niger”. 

Yours sincerely,

Kunyi Liu

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Dear colleagues, 

Thank you for corrections to improve the manuscript that I now recommnt for publication. 

Best regards