Microbial communities for plastic degradation: Role of metabolic complementarity in functional enhancement

Microbial communities for plastic degradation: Role of metabolic complementarity in functional enhancement

Abstract

Plastic pollution has rapidly transitioned from being a simple aesthetic inconvenience to a severe global problem. The durability of plastic material and low recycling rates have created numerous waste management challenges. This resulted in its accumulation in many different aquatic and terrestrial environmental niches. Some common,
and most environmentally damaging plastic waste disposal methods include incineration, ocean waste disposal and landfilling. In the past decade, biological and enzymatic routes for plastic disintegration have gained attraction as more sustainable options for waste management. Furthermore, these options have the potential to generate useful building blocks to be used as carbon source in bioprocessing, thus contributing to circular economy.

Biodegradation is the overarching term that describes the physicochemical transformation of polymers through the action of microorganisms which lead to the breaking down of long polymer chains into simple building blocks and subsequent formation of new biomass. While there are various global initiatives to harness this potential into a promising strategy, it is a very challenging task because the available natural molecular mechanisms for microbial degradation of synthetic compounds are sparse and work inefficiently.

Here we demonstrate the role of metabolic complementarity in addressing a complex biodegradation challenge. A naturally self-assembled microbial community was shown to grow on single source polyethylene as well as on complex single-use biological-grade laboratory waste as its sole carbon source. This community was able to accumulate meaningful amounts of biomass within a timeframe of four weeks and was identified to be heavily predominated (>80%) by Paenibacillus as shown in metagenomic analysis. Paenibacillus isolates from the community were then tested for their ability to utilise the carbon from plastics. The monoculture displayed a complete loss of function to propagate on plastic material implicating that the genus assumed a complementary role as part of the community. Our results show that metabolic interactions among these partners determine the extent and the ability of establishing a meaningful interdependent mechanism for effectively utilising plastic as carbon source. Community dominance, functional necessity and functional sufficiency were independent parameters, any of which cannot singlehandedly predict the performance of this microbial ecosystem in plastic
degradation.

BIOGRAPHY
Duygu Dikicioglu is an Associate Professor in Digital Bioprocess Engineering at the UCL Department of Biochemical Engineering. She is an Associate Member of the Institution of Chemical Engineers, a Member of the Society for Biological Engineering, and of the International Metabolic Engineering Society. Her research focuses on integrating systems biology, systems engineering and digital technologies for designing, understanding and improving cell systems and bioprocesses that utilise these systems. She also works in the digital space of automation and robotics, data structuring and standardisation, data driven and mechanistic modelling of systems, and data driven and hybrid process control for biosciences and bioindustries.