Biovalorization of lignin derived compounds with molasses as co-substrate for polyhydroxyalkanoate production

The bioconversion of 15 lignin-derived compounds (LDCs) into polyhydroxyalkanoate (PHA) was studied in the present study. PHA accumulating strain Burkholderia sp. ISTR5 was employed for the bioconversion of LDCs. Burkholderia sp. ISTR5 (R5) efficiently bioconverted LDCs into PHA. Due to low PHA yield on LDCs, the co-metabolism with agro-industrial waste molasses was studied, and it showed a considerable increase in the PHA production. With the supplementation of molasses, ∼20% increment in PHA production was observed on different LDCs. The highest increase in PHA percentage (w/w cell dry weight) after the addition of molasses was observed on 4-hydroxybenzoic acid (4-HBA) by 23%, followed by benzoic acid (22%) and gallic acid (21%). The Highest PHA accumulation was observed on p-coumaric acid (270 mg/L) followed by 4-HBA (260 mg/L) and gallic acid (256 mg/L). Produced PHA was characterized to be poly (hydroxybutyrate-co-hydroxyvalerate) (PHBV). The co-metabolism methodology considerably increased the PHA production and will be beneficial for setting up an agro-based efficient biorefinery.