Black soldier fly larval oil as a renewable substrate for tailored PHA production

Black soldier fly larvae (BSFL; Hermetia illucens) are environmentally friendly source of protein and also contain a significant amount of oil (BSFLO). BSFLO was compared with palm oil (PO) and crude palm kernel oil (CPKO) as new carbon sources for polyhydroxyalkanoate (PHA) synthesis using three Cupriavidus necator strains: H16 (wild type), Re2058/pCB113, and Re2160/pCB113 recombinants. BSFLO contained a relatively high amount of lauric acid (C12:0, 26.2%) and was suitable for cell growth and PHA synthesis. C. necator H16 produced more than 80 wt% poly(3-hydroxybutyrate) [P(3HB)] homopolymer with a cell dry weight (CDW) ranging from 8.52 to 9.26 g/L. To produce poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)], Re2058/pCB113 showed a higher CDW (8.35–9.07 g/L) with 69.2–73.9 wt% P(3HB-co-3HHx), which exhibited Re2160/pCB113 with a CDW of 3.24–3.64 g/L and 65 wt% P(3HB-co-3HHx). The 3HHx composition of the PHA produced by all three strains utilizing BSFLO ranged from 0 to 28 mol%. The average molecular weight (Mw) of the PHA was between 1.6 × 105 and 15.1 × 105 Da, and the melting temperature (Tm) ranged from 81 °C to 171 °C. BSFLO is a potential feedstock for PHA synthesis and can be used in combination with other oils to regulate the 3HHx molar fraction.