Comprehensive Techno-environmental Evaluation of a Pilot-Scale PHA Production from Food Waste in China

Polyhydroxyalkanoates (PHAs), a biodegradable
plastic that might
replace petroleum-based plastics, can be recovered from organic waste
using mixed microbial cultures (MMCs). Research in this field has
been ongoing for about 25 years and is now in a critical commercialization
period. However, few pilot-scale studies are available to analyze
its technical feasibility and environmental impact. We ran an MMC
PHA production pilot plant for 6 months using local food waste as
the feedstock. The traditional three-stage process achieved PHA content
of 47.91 ± 1.91% dry cell weight and volumetric productivity
of 9.94 ± 0.01 g/L·d, while a novel rapid proliferation
stage was built in, the PHA content and productivity could reach 41.39
± 2.39% cell dry weight and 20.02 ± 0.01 g/L·d, respectively.
Life cycle assessment using field data showed that greenhouse warming
potential was much more than five times that of the known literature,
and the fossil depletion potential was 10.30 (scenario #1)/7.59 (scenario
#2) times higher than petroleum-based polyethylene (PE) plastic. However,
establishing a resource–energy–water union instead of
an isolated plant could achieve environmental benefits compared to
PE plastic. This techno-environmental analysis provides emerging MMC
PHA producers worldwide with a valuable reference for further development
opportunities and market planning.