Three-Stage Solid-State Fermentation Technology for Distillers’ Grain Feed Protein Based on Different Microorganisms Considering Oxygen Requirements
, Longfei Weng 1, Dong Liu 3, Xiaoling Zhao 1, Jinmeng Chen 1, Jingliang Xu 1, Yafan Cai 1,* and Hanjie Ying 3
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe article presents an innovative three-step fermentation technology for producing animal feed proteins from distiller's grains, utilizing Aspergillus niger, yeasts, and lactic acid bacteria. The stages include aerobic, microaerophilic, and anaerobic conditions, with results showing improvements in reducing sugar concentration, protein content, and feed flavor. However, while the article addresses a relevant issue regarding protein shortages in China and offers an interesting solution, it would benefit from more specific data on China's protein needs and their impact on the livestock industry. The materials section is detailed, but it lacks precision regarding the storage duration of distiller's grains and the potential impact on sample quality. Additionally, the methodological choices are described without justification, and some methods are mentioned without appropriate references. Finally, the article does not separate the results from the discussion (with only a results section where the results are also discussed), which is a significant flaw for clarity. A clear separation between these sections is crucial for assessing the quality of the article, as it is required for journal publications.
Author Response
Please check the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsThe crrent study explored the feasibility of converting distillers’ grains into feed protein. Three different microorganisms (fungus, yeast, and LAB) were used at different stages to hydrolyze crude cellulose and protein. The highest sugar concentration of 36.9 mg g⁻¹ was obtained after pretreatment with Aspergillus niger. In the microaerophilic stage, the natural exchange of oxygen achieved the best true protein enhancement (from 10.8% to 16.4%) among the three oxygen supply modes. Exogenous supplementation with lactic acid bacteria had a positive impact on feed protein preservation and flavor enhancement. The submission can be accepted after major revision.
- What is the purpose of removing crude cellulose from grain waste? Can this be achieved through rumination? A comparison must be made.
- The enzyme activities at all stages, including cellulase, protease, and amylase, should be presented.
- What is the pH change after LAB supplementation?
- Figure 2: A more thorough discussion of Day 2 is expected.
- The significance of differences should be indicated in all figures and tables.
- Is there a plan to conduct an animal study? What are the potential benefits of the new fermented feed?
Minor revision is needed.
Author Response
Please check the attachment
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe author has successfully addressed several points raised in the article, which is appreciated. However, the results section remains poorly structured and creates confusion with the discussion. It is essential to improve this section by organizing it more clearly and in line with the expected standards for a scientific article.
Additionally, it would be preferable to update the references, prioritizing those published in the last three years to reflect recent advancements in the field.
Author Response
Please check the attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsI am happy with the revision now.
Comments on the Quality of English LanguageI am happy with the revision now.
Author Response
Please check the attachment
Author Response File: Author Response.docx
