Shirley Wong, Postdoctoral Fellow presents:
Towards valorization of food waste to bioplastic in Pseudomonas alloputida
Abstract:
Annually, over a billion tonnes of food is wasted, where it largely ends up in landfills and massively contributes to the emission of greenhouse gases. To improve global sustainability, this low-value carbon resource can instead be converted into high-value bio-based products. Microbial valorization of food waste has been validated for many applications, from biofuels to bioplastic polymers like polyhydroxyalkanoates (PHAs). Much effort has gone into processing heterogenous food waste towards such applications, such as anaerobic digestion to produce short-chain fatty acids (scFAs), a group of industrially-relevant fatty acids that can be used as building blocks for other bioproducts. Pseudomonas alloputida is a highly promising PHA producer but its ability to metabolize scFAs is limited.
To improve the capacity of PH production on scFAs and, therefore, enable its upcycling of food waste into high-value bioplastic, we are using functional metagenomics to mine exogenous carbon utilization pathways from the environment. Environmental microbial communities represent rich, untapped reservoirs of novel genes and metabolic pathways. Here, we present community analyses of compost and soil microbiomes enriched for utilization of short (C2-C5) versus medium chain fatty acids (C8 and C9) under conditions conducive to PHA accumulation. We are furthermore constructing metagenomic libraries from the enriched cultures using the broad-host-range cosmid pJC8, with an average insert size of 33 kb. The metagenomic libraries will enable us to functionally screen for, identify, and isolate exogenous metabolic pathways that could support scFA-PHA conversion by P. alloputida. Additionally, we further characterize the ability of engineered P. alloputida to use VFAs in bioplastic production, demonstrating its use in food waste valorization.
