# Polydroxyalkanoates Production from Simulated Food Waste Condensate Using Mixed Microbial Cultures

## TL;DR

This study explores using food waste condensate to produce biodegradable plastics called PHAs with mixed microbes.

## Contribution

The novel approach uses simulated food waste condensate as a substrate for PHA production with mixed microbial cultures.

## Key findings

- Both reactors achieved over 95% soluble COD removal and stable biomass growth.
- Higher organic load increased PHA accumulation to 19.05% and produced PHBV polymers.
- Proteobacteria became dominant, indicating successful enrichment of PHA-producing microbes.

## Abstract

The growing environmental concerns associated with petroleum-based plastics require the development of sustainable, biodegradable alternatives. Polyhydroxyalkanoates (PHAs), a family of biodegradable bioplastics, offer a promising potential as eco-friendly substitutes due to their renewable origin and favorable degradation properties. This research investigates the use of synthetic condensate, mimicking the liquid fraction from drying and shredding of household food waste, as a viable substrate for PHA production using mixed microbial cultures. Two draw-fill reactors (DFRs) were operated under different feed organic concentrations (2.0 ± 0.5 and 3.8 ± 0.6 g COD/L), maintaining a consistent carbon-to-nitrogen ratio to selectively enrich microorganisms capable of accumulating PHAs through alternating nutrient availability and deficiency. Both reactors achieved efficient organic pollutant removal (>95% soluble COD removal), stable biomass growth, and optimal pH levels. Notably, the reactor with the higher organic load (DFR-2) demonstrated a modest increase in PHA accumulation (19.05 ± 7.18%) compared to the lower-loaded reactor (DFR-1; 15.19 ± 6.00%), alongside significantly enhanced biomass productivity. Polymer characterization revealed the formation of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), influenced by the substrate composition. Microbial community analysis showed an adaptive shift towards Proteobacteria dominance, signifying successful enrichment of effective PHA producers.