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- RE: Questions on the paper
We have serious concerns about discrepancy between the description of the paper and the fact withdrawn from data.
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Our questions are shown below.
1. No information for the source of the PET film (1.9% crystallinity; lcPET) or the method to make the unusual PET film. It is well known that degradability is highly affected by crystallinity.
2. Fig. 1C: miscalculation
The weight of PET film (20150.2 mm) was described as 60 mg. However, as described in the Supplementary materials, the specific density of PET used was 1.3378 g/cm3 (approx. 1.34), giving a calculated weight of approximately 80.4 mg. Also, in Fig. S1 and Fig. 1H, the size and weight of PET film were described as 20150.2 mm and 60 mg, respectively.
3. Fig. 1C and 1H: measurement of weight loss
In our knowledge, to measure the weight of a film slip, it is necessary to remove the attached microbes on the surface, wash, and dry at least overnight at an appropriate temperature. Even for removing the enzyme from the surface, for example, dilute sodium bicarbonate and non-ionic surfactant are used (Oda et al. 2018). Typically a more powerful treatment is required to remove microbes, especially in the case of Ideonella sakaiensis or the consortium no. 46 that have cell appendages. The process to remove microbes was not described. In addition, was the film returned to the same test tube for further incubation? Based on the miscalculations described in 2, how could you obtain the reaso...Competing Interests: One of our research subjects is PET hydrolase from a thermophilic actinomycete. Therefore, we carefully read the paper including supplementary information and were led to the questions described above.