The Role of Yeast in the Valorisation of Food Waste

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript aims to illustrate the significance of utilizing yeast within the circular economy of food industry waste from a global perspective, along with considerations regarding relevant supporting policies. It provides a detailed and distinctive case study on yeast chassis technology, maintaining coherent logical progression throughout. The prospects for yeast chassis technology in supporting the establishment of a circular economy based on the bioconversion of food waste appear promising, and the proposed policy recommendations and measures are reasonable. However, I encourage the author to make some improvements to the text for further refinement and publication.

1. The text sections 1.1 and 1.2 lack necessary transitions. There should be an introduction to the key technologies and types in microbial synthesis technology, which would facilitate a comparison highlighting the advantages of yeast. It would be beneficial to address whether other microbes are less suitable than yeast as effective chassis for waste valorization. 

2. The introduction of yeast as a chassis for the valorization of food waste in section 2 is well done. However, in Table 2 and the accompanying text, it is important to note that the value of waste from certain distilled beverages, such as Baijiu and liquor, is closely tied to the specific yeast strains used，and the global proportion of the industrial sector cannot be overlooked, so I recommend including relevant information and context to support this discussion.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In the review paper by Murphy and O’Connell entitled »The Role of Yeast in Valorisation of Food Waste«, the authors evaluate and assess the role of yeast in the valorisation of food waste in the context of the circular bioeconomy. They emphasise the environmental and economic benefits of using yeast to convert food waste into valuable products, thereby reducing industrial waste and mitigating the effects of climate change. The review looks at the most common yeast strains used in the valorisation of food waste and their applications in the conversion of dairy, agriculture and food industry waste into biofuels, biochemicals and other value-added products. The study also discusses the regulatory and geographical aspects that could affect the feasibility of industrial applications of yeast in waste utilisation. In their conclusion, the authors predict the increasing use of yeast to produce bioethanol, biodiesel and other bioproducts from various food wastes and emphasise the need for further research into the versatility of yeast and the application of advanced, sustainable biotechnology practises.

The paper is well written and draws on more than one hundred referenced papers.

However, considering that sustainability of the biotechnology industry is also addressed in the manuscript, I would have expected that at least the possible negative effects of using fermentation processes on a large scale would also be mentioned. After all, it is well known that fermentation processes can also be a source of various greenhouse gases such as carbon dioxide, methane and nitrous oxide. I miss this part of the review and the addition of this point of view would - in my understanding - help to make this interesting review even more complete, especially when solutions to limit these negative effects of fermentation processes are already known to a certain extent.

Therefore,I recommend publishing the manuscript after a minor revision taking into account the points mentioned below:

1.) The adverse effects of large scale fermentation processes are at least briefly discussed

2.) The data from reference 93 should be correctly reproduced (“379 biogas/g” -> “379 mL biogas/g”

Author Response

Please see the attachment

Author Response File: Author Response.pdf