Growth Kinetics of Kazachstania unispora and Its Interaction with Lactic Acid Bacteria during Qymyz Production

Round 1

Reviewer 1 Report (Previous Reviewer 1)

Honoured Authors,

The manuscript in its present revised form is suitable for publication. 

Best wishes!

Reviewer 2 Report (Previous Reviewer 3)

The revised manuscript answers well the questions and comments of my previous review.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

The present manuscript is written very well and it is evident that the authors took a lot of effort to perform experiments and write a paper. The only thing that needs to be improved is the conclusion, which is written very poorly compared to the rest of the manuscript. 

Comments for author File: Comments.pdf

Author Response

Dear reviewer

Thank you for your review

We have added more details to the conclusion and made changes according to your comments

Best regards

Reviewer 2 Report

Dear authors, your work is intereating and very detailed in the mathematical part. I have however some remarks to do:

- You say that K. unispora strain have been sequenced and its identity confirmed by ITS sequencing. Has this ITS sequence (and all the sequences that you have obtained n this study) been deposited in an official database (i.e. GenBank)? Which was the identity percentage with K. unispora closest strain, as reported by Blast? Have you tried to compare your ITS sequence with the one of K. unispora type strain? If yes, which was the identity percentage?

- The conclusion section is very short, please add some content to it.

- Please add, if possible, a discussion section.

 

Minor remarks:

- all microorganisms names should be written in italic in all the tex, even in the figure captions and on the axis descritpions of the figures; please amend.

- Fiure 4 and 5 presents multiple panels that have not the same axis scale; in each figure, if possible, all the plots have to present the same scale. Please amend.

Author Response

Dear reviewer
Thank you for your review. Please see the attachment

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors submit a paper on characterization and modelling of cell growth dynamics in the yeast Kazachstania unispora and the impact of co-cultivation with Lactobacillus cultures. They also quantify volatile organic compounds (VOC). 

 

The work is basically a descriptive work on the growth parameters of the yeast strain and a study of co-cultivation growth and VOC production.

 

While the data reported are solid, it remains unclear whether statistics are sufficiently covered to allow for the general conclusions the authors draw. This concerns: the number of different strains tested is small (1 yeast strain, 2 Lactobacillus strains), the number of substrates (just 1 milk substrate). Also Experiments were done in duplicate – “in triplicate” would be the expected repetition.

 

Please explain why these specific strains of microorganisms (and not others among the isolates) were chosen.

 

 

 

Some additional questions:

 

Chapter 2.3.3: did you use the same number of cells from either strain for inoculation? Why? Did you do experiments with different concentrations or different ratios to determine the best concentration? Please explain.

 

Figure 4: this graph is very difficult to understand. Did you really use MRS medium or rather modified MRS as specified in the M+M section? And what is MRS medium enriched with lactose and reconstituted milk (see text in chapter 3.3.1)? Do you mean “in MRS (modified?) and in reconstituted milk”? Why are there no data points for “milk” at time 70 and 80? And can you please use identical axes dimensions in all graphs of fig. 4? What method was used to differentially quantify Lactobacillus and yeast in the co-cultures? The use of colour code (red dots) is not described in the legend.

 

Chapter 3.3.1: the authors present hypotheses on the different growth rates of yeast in co-cultivation. Theses can easily be tested by adding additional carbohydrates during the co-cultivation. This should be done to improve the impact of the data.

Also: please test (or at least discuss) what the impact of organic compounds produced is / may be on yeast growth kinetics.

 

Figure 8: please edit the legend and include the names of the strains (as given in the figure). Why is there a milk a and a milk b in the figure? Please explain. There is no control for the production of VOC by the yeast strain alone. Please add this.

 

Chapter conclusion: please carefully review the last sentence and edit the results section so that the conclusion can be better followed and understood.

 

 

 

 

 

 

 

 

Author Response

Dear reviewer
Thank you for your review. Please see the attachment

Author Response File: Author Response.pdf

Reviewer 4 Report

Kondybayev and others investigated the role of K. unispora in qymyz fermentation along with LAB. The purpose of the manuscript is quite important as the studies on K. unispora are not sufficient (particularly in qymyz fermentation). However, the manuscript should be improved to be published because of the following reasons.

 

The last paragraph of the Introduction section should be revised to clearly present the reasons why the study was conducted.

 

The authors used only a strain of K. unispora, but the reasons for this are not explained. This is important for readers to explain that this strain can be representative of the species in qymyz fermentation.

 

The explanation of backgrounds for experiments in each section of the Result and Discussion needs to be improved for better understanding of this study.

 

Data presentation in some figures are questionable.

In Figure 1, are units of the y-axis right?

In Figure 2A, the error bars are present in only three points.

In Figure 3, the units of the x-axis should be revised for ease of readability.

In Figure 4, 6, and 7, why the number of data points of each symbol is different?

Besides, all the figure captions did not fully explain the figures.

 

 In addition, the authors need to revise the manuscript carefully because there are many errors, typos, abbreviations that are not explained, wrong reference formatting in text, etc. Also, the authors should use line number function for ease of peer review.

Author Response

Dear reviewer
Thank you for your review. Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear authors, your answer about the identity of the strain is not comprehensive and satisfying. You cannot say "We just checked the identity of our strains using BLAST. The Y1.5 strain showed 99.69 % identity with Kazachstania unispora CBS 398 ITS region" without showing these data in the article. ALL the sequences of ALL the strains (yeast and bacteria) you have isolated must be uploaded in Genbank and their ID have to be reported in a table and added to the paper, in order to be available for referees and readers. 

Moreover, the quality of some figures is still low. Please add a new version of Figure 3, Figure 5, Figure 6 and Figure 7, with a higher resolution. Try to insert them in the article with a higher resolution, not as jpg or png with low dpi, in order to maintain their quality.

Author Response

Dear Reviewer

We have uploaded our sequences to Genbank. They will be released on Dec 16.

We have also increased resolutions of figures.

As for english editing we used MDPI service. The certificate is included

Thank you

Author Response File: Author Response.pdf

Reviewer 3 Report

The authors respond to all questions in the review. However, there is no evidence of this in the edited manuscript. The comments in the review were not meant as personal questions but requests to change the manuscript accordingly.

Author Response

Dear Reviewer

We have made changes according to your comments

Thank you,

 

Reviewer 4 Report

The authors addressed most of the comments. I think that other minor modifications would be completed during proofreading process.

Author Response

Dear reviewer

We have added more details to the paper according to comments of other reviewers.

Best regards