Microbial acclimatization to lipidic-waste facilitates the efficacy of acidogenic fermentation

•Microbial acclimatization improved lipidic-waste utilization in acidogenic fermentation.•Firmicutes, Bacteroidetes, and Cloacimonetes were abundant in the acclimatized microbiome.•Hydrogen productivity enhanced to 46 mL d−1 after acclimatization.•Hydrogenogenic acidogenesis and carboxylic chain elongation produced C4–C7 fatty acids.