Quorum-driven microbial consortium for Bioplastic production from agro-waste

Area of Science:

• Biotechnology
• Microbial Ecology
• Synthetic Biology

Background:

• Microbial consortia are vital in natural ecosystems.
• Polyhydroxyalkanoates (PHA) are biodegradable polymers with diverse applications.
• Agro-industrial residues present a sustainable feedstock for biopolymer production.

Purpose of the Study:

• To engineer a synthetic interkingdom microbial consortium for efficient PHA production.
• To utilize agro-industrial residues like Brewer's Spent Grain (BSG) and waste cooking oil (WCO) as feedstocks.
• To investigate the metabolic and genetic mechanisms underlying enhanced PHA accumulation.

Main Methods:

• Construction of a synthetic consortium using *Ophiostoma piceae* and *Pseudomonas putida* KT2440.
• Cultivation on BSG and WCO, with and without the quorum sensing molecule farnesol.
• Biochemical assays, microscopy, transcriptomics, and metabolomics analyses.
• Bioreactor scale-up experiments.

Main Results:

• *P. putida* accumulated up to 40.2% intracellular PHA, enhanced by farnesol.
• Farnesol increased *P. putida* proliferation and induced *phaG* gene expression while repressing *phaZ*.
• Trophic interactions involving citric acid and glycerol facilitated PHA synthesis.
• Bioreactor scale-up yielded 6.7 g·L^-1 PHA without substrate pretreatment.

Conclusions:

• The synthetic consortium effectively converts agro-industrial residues into PHA.
• Quorum sensing and inter-microbial trophic interactions are key to optimizing PHA production.
• The study lays the foundation for an industrial consolidated bioprocess (CBP) for sustainable PHA manufacturing.