Display omitted •First study exploring the effect of 3 key process parameters on the LD-DF of FVW.•Boosted H2 production at pH 7, 5% total solids and 1.8 g VSS/L cell concentration.•H2 production agreed with the lactate uptake and acetate and butyrate production.•Moderate H2 yield (50 mL/g VS) but an outstanding rate (976.4 mL/L-h) was achieved.•Lactate-based DF is a promising route to transform FVW into H2 at high rates. This study aims at investigating the influence of operational parameters on biohydrogen production from fruit-vegetable waste (FVW) via lactate-driven dark fermentation. Mesophilic batch fermentations were conducted at different pH (5.5, 6.0, 6.5, 7.0, and non-controlled), total solids (TS) contents (5, 7, and 9%) and initial cell biomass concentrations (18, 180, and 1800 mg VSS/L). Higher hydrogen yields and rates were attained with more neutral pH values and low TS concentrations, whereas higher biomass densities enabled higher production rates and avoided wide variations in hydrogen production. A marked lactate accumulation (still at neutral pH) in the fermentation broth was closely associated with hydrogen inhibition. In contrast, enhanced hydrogen productions matched with much lower lactate accumulations (even it was negligible in some fermentations) along with the acetate and butyrate co-production but not with carbohydrates removal. At pH 7, 5% TS, and 1800 mg VSS/L, 49.5 NmL-H2/g VSfed and 976.4 NmL-H2/L-h were attained.