Conversion of tomato waste into a poly (3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate) by a mixed microbial community

Tomato waste (TW) originating from tomato processing is produced in large quantities and has a low cost, presenting as an interesting feedstock for biotechnological valorization into value-added bioproducts. This study explored the utilization of TW as feedstock to produce polyhydroxyalkanoates (PHA) by a mixed microbial community. The bioprocess encompassed acidogenic fermentation of TW with a maximum yield of 0.22 +/- 0.05 gFP/gVS. A maximum PHA content of 66.8 +/- 11.0 wt.% was reached in the accumulation assays, with a yield of 0.75 +/- 0.10 CmmolPHA/CmmolFP. The biopolymer was composed of 3-hydroxybutyrate (3HB), hydroxyvalerate (3HV) and hydroxyhexanoate (3HHx) with an average composition of 82:11:7 (3HB:3HV:3HHx, molar basis) and similar mechanical and thermal properties to other 3HB:3HV:3HHx terpolymers and comparable to high density polyethylene and polypropylene. These findings demonstrated that TW can be used to efficiently produce a PHA terpolymer with properties that render it suitable for replacing petrochemical-derived plastics.