Enhancing the Methane Yield of Salicornia spp. via Organosolv Fractionation as Part of a Halophyte Biorefinery Concept

Abstract: The present research investigated the effect of organosolv pretreatment on two species of
salt-tolerant Salicornia spp. biomass, Salicornia dolichostachya and Salicornia ramosissima, for increasing
biomethane production through anaerobic digestion. The final biomethane yield of de-juiced green
fibers of Salicornia spp. from wet fractionation increased by 23–28% after organosolv treatment. The
highest methane yield of about 300 mL-CH4/gVS was found after organosolv treatment with 60%
v/v ethanol solution at 200 ◦C for 30 min, or at 180 ◦C for 30 or 60 min treatment time. Furthermore,
the methane production rate increased significantly, reducing the time until 95% of the final methane
yield was reached from 20 days to 6–10 days for the organosolv-treated biomass. This research shows
that the process of anaerobic digestion of halophyte biomass benefits from cascade processing of
Salicornia fibers in a biorefinery framework by sequential wet and organosolv fractionation for full
utilization of halophytic biomass.

Keywords: anaerobic digestion; organosolv pretreatment; methane production; biorefinery