Oil palm empty fruit bunch to biofuels and chemicals via SO2–ethanol–water fractionation and ABE fermentation.

Highlights: [•] Oil palm empty fruit bunches (OPEFB) are fractionated by SO2–ethanol–water mixture. [•] Fractionation of OPEFB feedstock produces cellulosic fibers and spent liquor. [•] Spent liquor contains dissolved hemicellulose sugars (mostly monomers) and lignin. [•] Fractionation and sugar hydrolysis is hindered by the high cation content of OPEFB. [•] Acidic leaching of OPEFB only partly removes cations; more intense deashing needed. [Copyright &y& Elsevier]