Nanostructured complex of reduced graphene oxide adorned with magnetite as an adsorbent for inhibitor compounds in wood hydrolysates

Abstract Lignocellulosic biomass is an abundant and renewable feedstock for biofuels, biochemicals and biomaterials. To make this recalcitrant biomass more susceptible to hydrolysis and microbial conversion a pretreatment is required. Many pretreatments have resulted in high sugar yields; however, they can generate microbial inhibitory compounds in the fermentation step. Therefore, the detoxification of hydrolysates is necessary. This study shows that reduced graphene oxide adorned with magnetite nanoparticles (rGO-MNPs) can adsorb inhibitory compounds such as furfural. Adsorption tests were performed in both aqueous solutions (furfural and furfural-glucose) and wood hydrolysate. rGO-MNPs (20 mg) removed 68% of furfural when it was alone, 49% of furfural when it was mixed with glucose and 20% of furfural in the wood hydrolysate. Among the adsorption of furfural in wood hydrolysate, rGO-MNPs adsorbed other lignin derivate compounds. Finally, no toxic effect of rGO-MNPs on R. toruloides-1588 was observed during the fermentation using detoxified wood hydrolysate.