Biodegradability of woody film produced by solvent volatilisation of Japanese Beech solution

Abstract

To address the problem of marine pollution from discarded plastics, we developed a highly biodegradable woody film, with almost the same components as wood, from the formic acid solution of ball-milled wood. We found that the woody film was not easily degraded by cultured solution of hand bacteria (phylum Proteobacteria was dominant). However, the film was easily biodegraded when in cultured solution of soil (Firmicutes, especially class Bacilli, was dominant) for 4 weeks at 37 °C, or when buried in the soil itself, both under aerobic conditions (Acidobacteria and Proteobacteria were dominant) for 40 days at room temperature and under anaerobic conditions (Firmicutes, especially family Ruminococcaceae, was dominant) for 5 weeks at 37 °C. Moreover, when film was buried in the soil, more carbon dioxide was generated than from soil alone. Therefore, the film was not only brittle but formed of decomposable organic matter. We showed that the film does not decompose at the time of use when touched by the hand, but it decomposes easily when buried in the soil after use. We suggest that this biodegradable woody film can be used as a sustainable raw material in the future.www.nature.com/scientificreports www.nature.com/scientificreports/ were then purified and pooled for sequencing. Sequencing was performed using the Illumina MiSeq platform at Kanazawa University. The raw sequence data were analysed following Hewawasam et al. 27 . Data were clustered to each operational taxonomic unit (OTU) at the 97% similarity level, and the assignment of OTUs was carried out using Greengenes 28 and PyNAST 29 .Creation of heat maps. Data were analysed in R 30 and R Studio (R-Tools Technology, Ontario, Canada).The R and R Studio can be downloaded from the following URL: https://cran.r-project.org/, https://rstudio.com/ products/rstudio/download/. We used the version 3.5.3 for R, and 1.1.463 for R Studio.The OTUs with a low frequency of appearance were excluded, and the samples with a small number of total reads were excluded. Subsequently, the "rarefy" function was performed with the package "vegan" 31 in order to compare samples with different numbers of reads. Heat maps are used for visualisation in data analysis and can be created from R's "heatmap" function. In this study, the heat map was generated using the package "heatmap3" 32 , which allows customisation of heat maps.