Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The papr title is "Advances in biopolymers: a comprehensive review of the circular economy" which many reviews with similar titels were publishe between 2020 -2025.

In addition paper has serious issue and I think they submited wrong file, such as the following, and it is better they corect it properly and resubmit the paper.

1. Table 1 summarizes the characteristics of the main biological polymers, as well as their advantages and disadvantages is missed in the text, in addition need to explain what is the summary of this comparison.

2.  table 2 legend is wrong “Table 2. This is a table. Tables should be placed in the main text near to the first time they are cited.” And has serious problem and need to reedit such as Hydrogel are groups of biopolymer such as gelatin, alginate,….. Also it is not mentioned in the text.
3. Figures quality is not proper and if they are own  elaboration, why they cited papers
4. citationthe In-Text Citations (like  Smith, 2023) don't align with the rules of the Reference List at the end( [1]).

Author Response

Dear reviewer,

In the next lines, the authors explain the corrections made to the manuscript, in accordance with the comments received.

Comments 1: Table 1 summarizes the characteristics of the main biological polymers, as well as their advantages and disadvantages is missed in the text, in addition need to explain what is the summary of this comparison.

Response 1. The explanation of Table 1 was added in the paragraph immediately below the table, on lines 113-125.

Comments 2. Table 2 legend is wrong “Table 2. This is a table. Tables should be placed in the main text near to the first time they are cited.” And has serious problem and need to reedit such as Hydrogel are groups of biopolymer such as gelatin, alginate,….. Also it is not mentioned in the text.

Response 2. The title of Table 1 was corrected in the numbering and the correct title was added to it.

Comments 3. Figures quality is not proper and if they are own  elaboration, why they cited papers.

Response 3. Quality of figures was improved. The title of figures was corrected and revised.

Comments 4. Citation the In-Text Citations (like  Smith, 2023) don't align with the rules of the Reference List at the end( [1]).

Response 4. The citation format was modified according to the journal's author guidelines.

Sincerely,

The author and co-authors

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript titled “Advances in biopolymers: a comprehensive review of the circular economy” by Hernández-Hernández, E.; et al. is a Review work where the authors addressed the most recent advances in the field concerning the design of the next-generation of green-friendly customized biopolymers suitable for many Industry manufacturing sector applications. This is a topic of growing interest and the manuscript is generally well-written.

However, it exists some points that need to be addressed (please, see them below detailed point-by-point) to improve the scientific quality of the submitted manuscript paper before this article will be consider for its publication in Sustainability.

1) Introduction. “Global bioplastic production reached 2.4 millions tons in 2021 (…) Biopolymers (…) are used in different applications” (lines 35-38). Could the authors provide quantitative data insights according to the relative percentages in the use of biopolymers indicating the specific application in different manufacturing Industry sectors as depicted in the Table 2. This will significantly aid the potential readers to better understand the significance of this devoted research and complement the content of the current subsection number 4.

 

2) “Plastic materials (…) negative impact on the environment, because of the big volume of residues generated. The current production suggests that in 2050 the planet will reach approximately 34 billion tons (…) Petroleum (…) causing harmful processes and pollution to the soil and water bodies for many years to come” (lines 45-56). Here, some data details concerning the economic impact related to recycling processes of plastic-based materials will also benefit to the potential readers.

 

3) Types of biopolymers from biological origin. “An example of biological polymers (…) such as lignin and phenolic compounds, which have a negative impact on nature” (lines 85-87). Here, even if I agree with this statement furnished by the authors, it should be also remarkable to discuss how depending on lignin structuration [1] can lead to a panoply of sustainable biopolymer composites for many applications [2]. This will strengthen the relevance to invest resources in this field.

[1] https://doi.org/10.1039/d5nr03153b

[2] https://doi.org/10.1016/j.clema.2024.100279

 

4) “While (…) polybutylene succinate polymers (…) attractive to the packaging industry” (lines 104-107). First, the abbreviation derived from the term “polybutylene succinate” (PBS) should be defined. Then, the discussion should be also expanded with other alternative polymer matrices as polybutylene adipate co-terephtalate. The properties and applications of PBS- and PBAT-based biopolymers should be also depicted in the Table 2 (line 110).

 

5) Composite materials made with biopolymers. “3.1. Main processes used to obtain biopolymers” (lines 137-204). Some information details concerning the reaction yields of the processes described in this subsection need to be stated.

 

6) Advantages and disadvantages of biopolymers of biological origin. This section discusses about the circular economy related to the biopolymers of biological origin. Could the authors provide further data insights regarding the life cycle assessment (LCA) and  life cycle cost (LCC) environmental footprints?

 

7) “7. Conclusions” (lines 454-495). This section perfectly remarks the most relevant outcomes found by the authors in this field, the promising future prospectives and also the potential future action lines to pursue the topic covered in this work. No actions are requested from the authors.

Author Response

Dear reviewer,

In the next lines, the authors explain the corrections made to the manuscript, in accordance with the comments received.

Comments 1: Introduction. “Global bioplastic production reached 2.4 millions tons in 2021 (…) Biopolymers (…) are used in different applications” (lines 35-38). Could the authors provide quantitative data insights according to the relative percentages in the use of biopolymers indicating the specific application in different manufacturing Industry sectors as depicted in the Table 2. This will significantly aid the potential readers to better understand the significance of this devoted research and complement the content of the current subsection number 4.

Response 1. Quantifiable data was added to complement the information already mentioned.

Comments 2: “Plastic materials (…) negative impact on the environment, because of the big volume of residues generated. The current production suggests that in 2050 the planet will reach approximately 34 billion tons (…) Petroleum (…) causing harmful processes and pollution to the soil and water bodies for many years to come” (lines 45-56). Here, some data details concerning the economic impact related to recycling processes of plastic-based materials will also benefit to the potential readers.

Response 2. Quantifiable data was added to complement the information already mentioned.

Comments 3: Types of biopolymers from biological origin. “An example of biological polymers (…) such as lignin and phenolic compounds, which have a negative impact on nature” (lines 85-87). Here, even if I agree with this statement furnished by the authors, it should be also remarkable to discuss how depending on lignin structuration [1] can lead to a panoply of sustainable biopolymer composites for many applications [2]. This will strengthen the relevance to invest resources in this field.

Response 3. Information was expanded on the effects of lignin structure on the characteristics of biopolymers.

Comments 4: “While (…) polybutylene succinate polymers (…) attractive to the packaging industry” (lines 104-107). First, the abbreviation derived from the term “polybutylene succinate” (PBS) should be defined. Then, the discussion should be also expanded with other alternative polymer matrices as polybutylene adipate co-terephtalate. The properties and applications of PBS- and PBAT-based biopolymers should be also depicted in the Table 2 (line 110).

Response 4. Abbreviations and grammar issues were corrected, in addition to reviewing the wording and adjusting the translation.

Comments 5: 5) Composite materials made with biopolymers. “3.1. Main processes used to obtain biopolymers” (lines 137-204). Some information details concerning the reaction yields of the processes described in this subsection need to be stated.

Response 5: Performance-related data was added in each case.

Comments 6: 6) Advantages and disadvantages of biopolymers of biological origin. This section discusses about the circular economy related to the biopolymers of biological origin. Could the authors provide further data insights regarding the life cycle assessment (LCA) and  life cycle cost (LCC) environmental footprints?

Response 6: Although the topic is centered on the production of bio-based polymers, it does not address issues central to life cycle analysis; it is more focused on biodegradability and ecological and economic production.

Comments 7: “7. Conclusions” (lines 454-495). This section perfectly remarks the most relevant outcomes found by the authors in this field, the promising future prospectives and also the potential future action lines to pursue the topic covered in this work. No actions are requested from the authors.

Response 7: No action was taken.

Sincerely,

The author and co-authors

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript can be accepted.