Enzymatic Synthesis and Characterization of Different Families of Chitooligosaccharides and Their Bioactive Properties
, Paloma Santos-Moriano 1,3, Antonio O. Ballesteros 1, Maria Fernandez-Lobato 2 and Francisco J. Plou 1,*Round 1
Reviewer 1 Report
Dear Editor,
here are my comments on the paper titled: “Enzymatic synthesis and bioactive properties of different families of Chitooligosaccharides”, by Miguez et al.
The review aimed to focus on the preparation, classification, and biological activity of chitooligosaccharides, an interesting wide family of chitin/chitosan derivatives.
In my opinion, the review design is appropriate and well organized and could be useful to reassume the state of art on the enzymatic synthesis of this important class of compounds.
However, some critical issues must be evidenced.
Even if it is rightly reported on the title, and is the core of the review, the term "chitooligosaccharides" is not reported in the keywords.
The paragraph dedicated to the bioactive properties of COS could be improved. In some cases, the biological activity is only cited: it could be good to do an effort to correlate the activity with the type of chitooligosaccharide?
There a lot of self-citations: in some cases, they could be avoided. I recommend a revision of the bibliography trying to limit them (there are as many as 9 papers related to the authors compared to the total of 87 reported papers – more than 10%).
For instance, an interesting, recent, correlated paper by Arnold (Mar. Drugs 2020, 18(2), 93; https://doi.org/10.3390/md18020093) is not cited.
Author Response
The review aimed to focus on the preparation, classification, and biological activity of chitooligosaccharides, an interesting wide family of chitin/chitosan derivatives. In my opinion, the review design is appropriate and well organized and could be useful to reassume the state of art on the enzymatic synthesis of this important class of compounds.
Authors: We appreciate the reviewer’s comments.
However, some critical issues must be evidenced.
Even if it is rightly reported on the title, and is the core of the review, the term "chitooligosaccharides" is not reported in the keywords.
Authors: We have included the term "chitooligosaccharides" in the keywords
The paragraph dedicated to the bioactive properties of COS could be improved. In some cases, the biological activity is only cited: it could be good to do an effort to correlate the activity with the type of chitooligosaccharide?
Authors: We mention in line 297 that “In many cases, the chemical composition and molecular weight of COS are not fully determined before the assay”. For that reason, it is difficult to correlate the bioactivity with the chemical composition of the COS. We have included in this mini-review the limited information available regarding this correlation. For example, in line 307 we say that “partially acetylated COS (paCOS) exhibit better antibacterial activity towards Listeria monocytogenes and Escherichia coli than fully deacetylated COS (fdCOS)”. We have focused on the effect of COS composition on anti-inflammatory properties, for which there was more information than for other properties.
In summary, we agree with the reviewer that the influence of COS type on the properties is a key point. For that reason, the main objective of this mini-review is to emphasize the importance of synthesizing and characterizing COS of specific families, which would allow to expand the structure-function studies of these compounds.
There a lot of self-citations: in some cases, they could be avoided. I recommend a revision of the bibliography trying to limit them (there are as many as 9 papers related to the authors compared to the total of 87 reported papers – more than 10%). For instance, an interesting, recent, correlated paper by Arnold (Mar. Drugs 2020, 18(2), 93; https://doi.org/10.3390/md18020093) is not cited.
Authors: We have revised the bibliography according to the reviewer’s suggestions.
We have removed two papers related with the authors (we believe that the rest of references involving the authors of this mini-review is very related with the topic of chitooligosaccharides):
28. Alcalde, M.; Ferrer, M.; Plou, F.J.; Ballesteros, A. Environmental biocatalysis: from remediation with enzymes to novel green processes. Trends in Biotechnology 2006, 24, 281-287.
61. Neifar, S.; Cervantes, F.V.; BenHlima, H.; Bouanane-Darenfed, A.; Ballesteros , A.O.; Plou, F.J.; Bejar, S. Immobilization of the glucose isomerase from Caldicoprobacter algeriensis on Sepabeads EC-HA and its efficient application in continuous High Fructose Syrup production using packed bed reactor. Food Chemistry 2020, 309, 30.
We have updated the bibliography and two new references have been added to the manuscript, including that from Arnold. A new sentence has been included in lines 148-151 indicating the potential of LPMOs to hydrolyze chitin:
More recently, lytic chitin monooxygenases (LPMOs, EC 1.14.99.53) are being investigated as auxiliary enzymes for COS synthesis, as they are able to break down β(1→4) bonds in crystalline chitin by oxidation, thus facilitating the attack by chitinases [47].
47. Arnold, N.D.; Brück, W.M.; Garbe, D.; Brück, T.B. Enzymatic Modification of Native Chitin and Conversion to Specialty Chemical Products. Marine Drugs 2020, 18, 93.
We have also included a recent reference on prebiotic properties of COS. There is a new sentence in lines 320-322:
The fermentation of COS in vitro and its effect on human fecal microbial community structure and metabolites have been recently reported [80].
80. Ji, X.-G.; Chang, K.-L.; Chen, M.; Zhu, L.-L.; Osman, A.; Yin, H.; Zhao, L.-M. In vitro fermentation of chitooligosaccharides and their effects on human fecal microbial community structure and metabolites. LWT 2021, 144, 111224.
Reviewer 2 Report
the authors presented an overview of both others' works and their own on the preparation of various groups of chitooligosaccharides.Some of the properties of these compounds are also presented. In general, this mini-review can be published in its present form. On the other hand, the authors paid much attention to obtaining various fractions of chitooligosaccharides. Their biological action is described in much less detail. This is possible, but then the title of the review should probably be slightly modified. If the title remains the same, it is worth expanding the last sections of the review.
Author Response
The authors presented an overview of both others' works and their own on the preparation of various groups of chitooligosaccharides. Some of the properties of these compounds are also presented. In general, this mini-review can be published in its present form.
Authors: We appreciate the reviewer’s comments.
On the other hand, the authors paid much attention to obtaining various fractions of chitooligosaccharides. Their biological action is described in much less detail. This is possible, but then the title of the review should probably be slightly modified. If the title remains the same, it is worth expanding the last sections of the review.
Authors: We agree with the reviewer. The aim of this mini-review was to emphasize the importance of synthesizing and characterizing COS of specific families, which would help to understand the structure-function relationships in the studies of the bioactivities of these substances. We have slightly modified the article according to the reviewer’s suggestion:
Old title: Enzymatic synthesis and bioactive properties of different families of chitooligosaccharides
New title: Enzymatic synthesis and characterization of different families of chitooligosaccharides and their bioactive properties
