(686d) Engineering and Systems Biology of Robust Gut Microbial Communities for Polyolefin Degradation

Plastics are versatile, resilient and economical materials that account for up to 10% of all petroleum usage. That same environmental resilience, however, is a significant carbon sink for dwindling fossil fuel feedstocks at end of life. Moreover, plastics wastes pose a significant threat to plant, animal, and human health life due to mismanagement and uneconomical processes for their capture and recycling. Biological plastics upcycling presents a sustainable and economically viable alternative to reuse waste carbon from plastics due to their operation at ambient conditions, biocatalytic flexibility on mixed waste streams, and product selectivity. However, no known microbial systems process plastics waste at industrially relevant rates. To address this, we study and develop microbial consortia from the digestive tracts of yellow mealworms (larvae of Teneberio molitor) that degrade plastics much faster than microbes found in soil and marine environments. Gut extracts from the yellow mealworm are able to reduce polyethylene molecular weight by up to 3 orders of magnitude due in part to the concerted actions of its gut microbiome. Gut microbial isolates from mealworms fed a plastic-rich diet oxidize and modify polyethylene in isolation, but do not degrade or metabolize polyethylene as the sole carbon source, underscoring the need for rich microbial interactions for plastics biodegradation. We are able to recreate metabolic activity on plastics when microbial isolates are cultivated with fungi due to fungal secretion of a biofilm to facilitate microbial colonization of microplastic particles. More importantly, these synthetic consortia display novel physical linkages and mechanical processing of the plastics by the fungi to support bacterial growth. Synthetic consortia development is supported by classical microbiological approaches, systems biology analyses, and affinity-based probes that mimic polyolefin substrates for community enrichment. In this talk, I will discuss the structure of robust polyolefin degrading microbial communities and our efforts to elucidate microbial strains and guilds responsible for these phenotypes. In so doing, we establish design rules for efficient plastics degradation by synthetic microbial consortia.