An innovative strategy to enhance the ensiling quality and methane production of excessively wilted wheat straw: Using acetic acid or hetero-fermentative lactic acid bacterial community as additives

•Ensiling EWS with acetic acid or heterofermentative LAB addition was first studied.•Ensiling EWS with additives enhanced acetic acid fermentation.•Ensiling EWS with additives preserved hemicellulose and cellulose content.•Ensiling EWS with additives changed the homo-fermentation to hetero-fermentation.•Ensiling EWS with additives improved the methane yield by 17.7–23.9%.