Physio-chemical pretreatments for improved methane potential of Miscanthus lutarioriparius

•Miscanthus is a potential feedstock for methane production.•Methane yields from Miscanthus waste increased with decreasing particle sizes.•Pre-treatments led improvements in both sCOD and methane yields.•Mild alkaline pre-treatment was most efficient in enhancing methane yield and rate.•Competition for biomass for food/feed is avoided by converting Miscanthus to methane.