The article provides significant advancements in the understanding of polystyrene (PS) degradation by microorganisms, yet a few areas require further clarification and refinement.
In Figure 1, the degradation rate differences between solid and liquid states are visually compelling. However, the quantification relies heavily on weight loss, which might overlook non-degraded PS fragments or byproducts. It would be beneficial for the authors to include data from complementary techniques, such as high-resolution microscopy or mass spectrometry, to confirm complete degradation.
Regarding Figure 3, the analysis of carbon binding energy using XPS is well-illustrated. However, the absence of functional group detection in the FT-IR analysis for solid-state PS, despite XPS indicating oxidation, raises questions about the consistency of the findings.
The identification of proteins expressed during PS degradation, especially the novel bands observed in liquid-state reactions, is a highlight of the study. Nevertheless, the role of these proteins in the degradation pathway remains speculative. Functional validation through knockout or overexpression experiments would strengthen the proposed mechanisms.
Lastly, the exclusion of degradation byproducts in the analysis is a critical oversight. These products could influence the environmental feasibility and safety of the proposed degradation system. A thorough analysis of byproducts would provide a more holistic view of the process’s environmental implications.