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Propionate-oriented kitchen waste fermentation for polyhydroxyalkanoate production by mixed microbial cultures
Xiaolei Zhang1, Yingxue Sun2, Shaoping Luo2
1School of Ecology and Environment, Harbin Institute of Technology (Shenzhen), Shenzhen 518055, PR China; Shenzhen Key Laboratory of Water Resource Utilization and Environmental Pollution Control, Shenzhen 518055, PR China.
Bioresource Technology
|July 31, 2026
Summary
Kitchen waste fermentation can produce polyhydroxyalkanoates (PHA) using mixed microbial cultures (MMCs). Optimizing volatile fatty acid (VFA) composition, particularly increasing propionate, enhances PHA production efficiency and microbial performance.
Area of Science:
- Biotechnology
- Environmental Science
- Microbiology
Background:
- Kitchen waste fermentation offers a sustainable, low-cost carbon source for polyhydroxyalkanoate (PHA) production.
- Volatile fatty acid (VFA) composition significantly impacts PHA production by mixed microbial cultures (MMCs), but optimal conditions are not fully understood.
Purpose of the Study:
- To investigate the influence of different VFA compositions (acetate, propionate, butyrate) on PHA-producing microbial enrichment and production performance.
- To explore glycerol-assisted kitchen waste fermentation for enhanced propionate formation and subsequent PHA production.
- To identify limiting factors in actual kitchen waste fermentation for PHA production.
Main Methods:
- Comparison of MMC performance with acetate-, propionate-, and butyrate-dominant VFAs.
- Optimization of glycerol-assisted kitchen waste fermentation conditions (pH, temperature).
- Analysis of PHA content, productivity, carbon conversion efficiency, and microbial community dynamics.
Main Results:
- Propionate-dominant VFAs demonstrated superior substrate-switching adaptability and biomass retention, leading to the highest PHA productivity (0.94 g PHA/(L·d)).
- Optimized glycerol-assisted fermentation achieved ~41% propionate in VFAs, resulting in 42.5% PHA content and 48.3% carbon conversion efficiency.
- Elevated nutrient and salinity levels in actual fermentation broth limited performance compared to simulated conditions.
Conclusions:
- Increasing the propionate fraction in VFAs is a viable strategy for enhancing MMC-based PHA production.
- Glycerol-assisted kitchen waste fermentation is a promising approach for propionate-oriented PHA production.
- Addressing nutrient and salinity limitations in real waste streams is crucial for further optimizing PHA yields.
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