Optimization and characterization of PHA from isolate Pannonibacter phragmitetus ERC8 using glycerol waste

Area of Science:

• Biotechnology
• Polymer Science
• Microbial Engineering

Background:

• Polyhydroxyalkanoates (PHAs) are biodegradable polymers offering a sustainable alternative to petrochemical plastics.
• High production costs currently hinder widespread industrial adoption of PHAs.
• Utilizing waste streams for PHA production can significantly reduce manufacturing expenses.

Purpose of the Study:

• To optimize polyhydroxyalkanoate (PHA) production using Pannonibacter phragmitetus ERC8.
• To investigate the use of glycerol waste as a cost-effective carbon source for PHA synthesis.
• To enhance PHA yield through statistical experimental design and bioreactor scale-up.

Main Methods:

• Screening of low-cost substrates including glycerol waste, food waste, mutton tallow, whey, sugarcane bagasse, and corn steep liquor for PHA accumulation.
• Optimization of key fermentation parameters such as glycerol waste concentration, BHM concentration, and inoculum density using Response Surface Methodology (RSM).
• Validation of the optimized model and scale-up of PHA production in a laboratory-scale bioreactor.

Main Results:

• Pannonibacter phragmitetus ERC8 demonstrated potential for PHA accumulation using various low-cost substrates.
• Optimized conditions yielded a maximum PHA concentration of 1.36 g/L after 96 hours.
• Scale-up in a 5L bioreactor achieved a PHA production of 1.87 g/L.
• NMR spectroscopy confirmed the PHA composition as a heteromonomer of (R)-3-hydroxybutyrate and medium-chain-length 3HA monomers.

Conclusions:

• Glycerol waste is a viable and cost-effective carbon source for PHA production by Pannonibacter phragmitetus ERC8.
• The optimized fermentation process significantly enhances PHA yield.
• The study demonstrates a scalable and economical approach for producing PHAs, promoting their industrial application as biodegradable polymers.