Valorization of biodiesel-derived crude glycerol for simultaneous biosynthesis of biodegradable polyhydroxybutyrate and exopolysaccharide by the newly isolated Burkholderia sp. SCN-KJ.

This study demonstrated that Burkholderia sp. SCN-KJ is a promising novel species for the biovalorization of crude glycerol to polyhydroxybutyrate (PHB) and galactose-rich heteroexopolysaccharide (EPS). Whole-genome and genetic evolution analyses revealed separation of the different clades according to the ANIb and dDDH analyses, which confirmed that Burkholderia sp. SCN-KJ is a novel species. The highest PHB production from crude glycerol was 12.9 ± 0.4 g/L (72.9 ± 2.1 % w/w), with a productivity of 0.46 g/L/h and Y of 0.3 g/g at 28 h in a 10 L fermenter. The galactose-rich hetero-EPS began to be produced after nitrogen depletion, resulting in a concentration of 22.4 ± 0.2 g/L at 38 h. Examination of the carbon-to‑nitrogen ratio (C/N) showed that nitrogen-rich condition (C/N 20) was optimal for PHB production, whereas nitrogen-depleted condition promoted EPS production, showing two different extrema. The findings showed that Burkholderia sp. SCN-KJ has the potential to transform the landscape of biovalorization for sustainable production.