Algal biochar mediated detoxification of plant biomass hydrolysate: Mechanism study and valorization into polyhydroxyalkanoates

In this study, fourteen types of biochar produced using seven biomasses at temperatures 300 degrees C and 600 degrees C were screened for phenolics (furfural and hydroxymethylfurfural (HMF)) removal. Eucheuma spinosum biochar (EB-BC 600) showed higher adsorption capacity to furfural (258.94 +/- 3.2 mg/g) and HMF (222.81 +/- 2.3 mg/g). Adsorption kinetics and isotherm experiments interpreted that EB-BC 600 biochar followed the pseudo-first -order kinetic and Langmuir isotherm model for both furfural and HMF adsorption. Different hydrolysates were detoxified using EB-BC 600 biochar and used as feedstock for engineered Escherichia coli. An increased polyhydroxyalkanoates (PHA) production with detoxified barley biomass hydrolysate (DBBH: 1.71 +/- 0.07 g PHA/L), detoxified miscanthus biomass hydrolysate (DMBH: 0.87 +/- 0.03 g PHA/L) and detoxified pine biomass hydrolysate (DPBH: 1.28 +/- 0.03 g PHA/L) was recorded, which was 2.8, 6.4 and 3.4 folds high as compared to undetoxified hydrolysates. This study reports the mechanism involved in furfural and HMF removal using bio-char and valorization of hydrolysate into PHA.