Experimental and Computational Insights into Polyurethane Plastic Waste Conversion to Microbial Bioplastic

Area of Science:

• Biotechnology
• Environmental Microbiology
• Polymer Science

Background:

• Polyurethane plastic waste (PUPW) poses significant environmental challenges.
• Microbial production of bioplastics like polyhydroxyalkanoates (PHA) offers a sustainable alternative.
• Identifying efficient microbial strains and optimizing their growth conditions are crucial for PHA synthesis.

Purpose of the Study:

• To optimize fermentation conditions for maximum PHA yield from PUPW.
• To investigate the potential of Pseudomonas rhizophila S211 for PHA bioproduction.
• To explore the enzymatic capabilities of P. rhizophila S211 for PUPW degradation.

Main Methods:

• A seven-factor Hoke experimental design and response surface methodology were employed.
• Optimization of fermentation parameters including pH, temperature, NaCl, PUPW concentration, inoculum size, and incubation time.
• Genomic analysis of P. rhizophila S211 to identify PUPW-degrading enzymes and computational elucidation of polyurethanase properties.

Main Results:

• The highest PHA yield of 0.80 g/L was achieved under optimized conditions: pH 8, 35°C, 5% NaCl, 1% PUPW, 15% inoculum, monoculture of P. rhizophila S211, and 6 days incubation.
• The Hoke design model accurately predicted experimental results, validated by analysis of variance.
• Genomic and in-silico analyses predicted the presence of necessary enzymatic machinery in P. rhizophila S211 for PUPW conversion.

Conclusions:

• P. rhizophila S211 is a promising microorganism for converting polyurethane plastic waste into PHA bioplastics.
• Optimized fermentation conditions significantly enhance PHA yield.
• Integrated experimental and computational approaches confirm the microbial potential for bioremediation and bioplastic production from plastic waste.