Biochar-assisted dark fermentative biohydrogen generation: Statistical approach for integrated optimization of peach pomace hydrolysis and biochar production

Peach pomace (PP) was valorized into biochar (BC) and employed successfully to enhance biohydrogen production from PP hydrolysate (PPH) via dark fermentation. Box–Behnken Design (BBD) was applied to optimize BC production parameters, including temperature (300–650 °C), residence time (60–240 min), and heating rate (1–20 °C/min). The optimal BC was obtained at 650 °C, 88 min, and 20 °C/min, maximizing C C band transmittance and exhibiting favorable structural and surface properties. PP was hydrolyzed under optimized conditions (pH 5.8, 100 °C, 62 min), achieving 86% sugar recovery. Batch experiments were conducted under mesophilic conditions with varying BC and substrate concentrations. The maximum biohydrogen yield of 2.86 mmol H 2 /mmol total sugar and a production rate of 0.26 mmolH 2 /h were obtained at 1 g/L BC and 10 g/L total sugar concentration. The addition of BC markedly improved biohydrogen production by 1.65-fold compared to the control, clearly demonstrating that BC plays a crucial role in improving biohydrogen. • Peach pomace was converted to biochar to boost biohydrogen production. • C C band transmittance and minimum island size was achieved to get a good biochar. • Peach Pomace biochar and hydrolysate can be optimized effectively via BBD Method. • Dark biohydrogen fermentation was enhanced by 1.54-fold with biochar addition. • A hydrogen production yield of 2.86 mmol H 2 /mmol TS was obtained with biochar support.