Comparison of alkali and ionic liquid pretreatment methods on the biochemical methane potential of date palm waste biomass

[Display omitted] •An ionic liquid pretreated date palm waste biomass showed highest BMP efficiency.•Ionic liquid pretreatment highly deconstructed structural components of biomass.•Chemical composition and date palm waste biomass biodegradability were correlated.•Biomass chemical composition and morphologies strongly influencing methane yield.•Date biomass might be used as carbon-rich substrate for fermentable sugar recovery. Date palm waste biomass is a readily accessible agricultural waste biomass that may be used to produce biogas. Because the complex structure of date palm waste biomass prevents the embedded holo-cellulosic sugars from biodegrading, pretreatment is required to increase methane (CH4) yield. The present investigation aimed to comparatively determine the impact of alkali and ionic liquid pretreatment on the biochemical methane potential (BMP) of different types of date palm waste biomass. The findings revealed that ionic liquid pretreated Palm and Fruit bunch showed the highest BMP (321.67 mL CH4/g-TS) and substrate conversion efficiency (68.01%), respectively, over other biomass samples. In alkali pretreatment, the highest BMP and substrate conversion efficiency were detected with Palm (309.76 mL CH4/g-TS) and Spathe (62.09%). The high BMP and substrate conversion efficiency of date palm waste biomass may be harnessed for bioenergy production when this ionic liquid pretreatment technology is used.