Establishment of the upstream processing for renewable production of hydrogen using vermicomposting-tea and molasses as substrate

•Vermicomposting-tea is an attractive methodology for producing biohydrogen at 25 °C.•Vermicomposting-tea fermentation requires neither salts nor vitamins.•Using molasses as a substrate contributes to the circular economy of this waste.•Upstream processing and optimization were established for scaling-up.•This consortium is capable of tolerating heat-shocks of up to 24 h. This study aimed to establish the optimal operational conditions for hydrogen production using vermicomposting-tea and sugarcane molasses as substrate. The experiments were carried out by triplicate in 110 ml serological bottles, a Box-Behnken design of experiments was performed in anaerobic dark conditions. The maximal hydrogen production (HP), hydrogen production rate (HPR), and hydrogen yield (HY) attained were 1021.0 mlL-1, 5.32 mlL-1h-1, and 60.3 mlLH2-1/gTCC, respectively. The statistical model showed that the optimal operational conditions for pH, molasses concentration, and temperature were 6.5; 30 % (v/v) and 25 °C. The bioreactor run showed 17.202 L of hydrogen, 0.58 Lh-1, and 77.2 mlH2gTCC-1 For HP, HPR, and HY. Chemometric analysis for the volatile fatty acids obtained at the fermentation showed that only two principal components are required to explain 90 % of the variance. The representative pathways for hydrogen production were acetic and butyric acids. This study established the operational conditions for the upstream processing amenable to pilot and industrial-scale operations. Our results add value to molasses within the circular economy for hydrogen production using a novel consortium from vermicompost.