Techno-economic evaluation and life-cycle assessment of poly (3-hydroxybutyrate) production within a biorefinery concept using sunflower-based biodiesel industry by-products

This study presents techno-economic evaluation of a biorefinery concept using biodiesel industry by-products (sunflower meal and crude glycerol) to produce poly(3-hydroxybutyrate) (PHB), crude phenolic extracts (CPE) and protein isolate (PI). The PHB production cost at two annual production capacities ($12.5/kg for 2,500 t PHB/ year and $7.8/kg for 25,000 t PHB/year) was not cost-competitive to current PHB production processes when the revenues derived from co-products were not considered. Sensitivity analysis projected the economic viability of a biorefinery concept that could achieve a minimum selling price of $1.1/kg PHB similar to polypropylene. The annual PHB production capacity and the identification of marketable end-uses with respective market prices for the co-products CPE and PI were crucial in attaining process profitability. Greenhouse gas emissions (ca. 0.64 kg CO2-eq/kg PHB) and abiotic depletion potential (61.7 MJ/kg PHB) were lower than polypropylene. Biorefining of sunflower meal and crude glycerol could lead to sustainable PHB production.