Agro-Industrial Food Waste as a Low-Cost Substrate for Sustainable Production of Industrial Enzymes: A Critical Review
, Mei-Ling Tsai 2,†, Parushi Nargotra 2,†, Chiu-Wen Chen 1,3, Chia-Hung Kuo 2, Pei-Pei Sun 2,* and Cheng-Di Dong 1,3,*
Round 1
Reviewer 1 Report
This paper presents an excellent review of bioconversion of agro-industrial food waste into valuable products using enzymes, embracing several important areas such as agro-industrial food waste use as enzyme source, as carriers for enzyme immobilization and substrates for biocatalytic reactions. The review is deep, critical, and comprehensive. The manuscript is well written. The only shortcoming of this paper is very limited number of figures. I would suggest authors add more figures (from literature) to illustrate their findings.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The review manuscript deals with the use of agro-industrial waste for the production of industrial enzymes. The manuscript is well organized and covered most of the recent updates. Only one minor comment is on the title. The title needs to be revised as the manuscript covering only enzymes, not any products. Hence the title may be changed as "Sustainable bioconversion of agro-industrial food waste into industrial enzymes: A critical review"
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript brings a high quantity of relevant information about enzyme production and application. However, it is not well organized. First of all, the content of the review is not in accordance with the title “Sustainable bioconversion of agro-industrial food waste into valuable products using enzymes: A critical review”. The production of bioproducts is not the main focus or explored. In fact, it is not well mentioned what could be produced from agro-food wastes. I suggest the inclusion of a figure illustrating the possibilities, such as xylitol, biogas, bioethanol, xylooligossacharides, enzymes itself, among other. Other major points are:
· In the entire manuscript it is confusing if authors are focusing on the use of agro-food waste to produce enzyme or to use it as substrate by enzymes to produce bioproducts. If both, it is necessary to reorganize the text and maybe separate into 2 sections: “enzyme production from agro-food wastes” and “enzyme application on agro-food wastes to produce bioproducts”.
· In general authors explores all topics superficially and not critically as claimed. Which are the challenges, advantages, disadvantages and trending? Specially on enzyme immobilization section, where authors only report some results from literature, which are not necessarily the best, and there is a lack of discussion about mass transfer, methods that increase more the stability and why? Challenges like enzyme desorption and loss of activity during immobilization. In addition, Table 1 focus only in immobilization supports which are composed by agro-food waste. I suggest to change the entire immobilization topic focusing only in the application of such residues as a carrier.
· A section, or a paragraph, about currently enzyme costs is important to emphasize the necessity of using low cost and renewable raw materials for enzyme production. The following article can be helpful , https://doi.org/10.1016/j.esd.2022.03.007 , once it has such information about enzyme price and contribution of enzyme cost on product price.
· Please check carefully the manuscript looking for English errors.
· A list of abbreviations is necessary to better understand the manuscript, such as SSF, SmF, etc
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
The authors made the requested changes appropriately. The manuscript is well written and brings important information to the area, so I recommend its publication.
