(663d) Polymer-Degrading Potential of a Diverse Set of Environmentally Ubiquitous Microorganisms Using High-Throughput Biodegradation Testing

With the growing accumulation of plastic waste, great focus has been directed towards the development of polymers with short lifespans in the natural environment. One solution is the use of biodegradable polymers, functionally-useful structures with the ability to be enzymatically-broken down by microorganisms. To determine the effectiveness of these new polymers, a biodegradation test must be performed; however, these tests often take many months and are often unstandardized. Recently, a high-throughput method to determine biodegradability was developed to address this need using clear-zone assays, but this method uses a single species, P. lemoignei. To better reflect natural conditions and encompass the environmental enzymatic scope, this work expanded the method to new species. Initially, ununiform colony morphology made this expansion difficult, but it was found that colony shape can be controlled using media composition and richness. An exploration of culturing conditions and media compatibility was required, leading to the detailed screening of a set of minimal media on each species. In some cases, limited carbon availability encouraged polymeric breakdown, emphasizing the effect of culturing conditions on depolymerase expression. Using these new conditions, this method was used to determine the unexplored degrading capability of 20 polymer-degrading species on 13 commercial polymers. These results emphasize the difference in degrading-capability of key degraders while emphasizing the importance of microbial diversity in polymer biodegradation. Trends between polymer structure and specific microbial species are clearly evident with certain species favoring specific functional groups over others, and particular polymeric structures and classes are shown to be generally favored for degradation.