Influence of carbohydrates and proteins concentration on fermentative hydrogen production using canteen based waste under acidophilic microenvironment

Functional role of biomolecules viz., carbohydrates and proteins on acidogenic biohydrogen (H2) production was studied through the treatment of canteen based composite food waste. The performance was evaluated in an anaerobic sequencing batch reactor (AnSBR) at pH 6 with five variable organic loading conditions (OLR1, 0.854; OLR2, 1.69; OLR3, 3.38; OLR4, 6.54 and OLR5, 9.85 kg COD/m3-day). Experimental data depicted the feasibility of H2 production from the stabilization of food waste and was found to depend on the substrate load. Among the five loading conditions studied, OLR4 documented maximum H2 production (69.95 mmol), while higher substrate degradation (3.99 kg COD/m3-day) was observed with OLR5. Specific hydrogen yield (SHY) vary with the removal of different biomolecules and was found to decrease with increase in the OLR. Maximum SHY was observed with hexose removal at OLR1 (139.24 mol/kg HexoseR at 24 h), followed by pentoses (OLR1, 108.26 mol/kg PentoseR at 48 h), proteins (OLR1, 109.71 mol/kg ProteinR at 48 h) and total carbohydrates (OLR1, 58.31 mol/kg CHOR at 24 h). Proteins present in wastewater helped to maintain the buffering capacity but also enhanced the H2 production by supplying readily available organic nitrogen to the consortia. Along with carbohydrates and proteins, total solids also registered good removal.

► Bioenergy generation along with treatment of canteen based food waste was studied during acidogenic fermentation process.
► The functional role of biomolecules viz., carbohydrates and proteins on acidogenic H2 production was evaluated.
► Study depicts the involvement of hexoses and pentoses on H2 production and proteins in maintaining the buffering capacity.
► COD, total carbohydrates, hexoses, pentoses, proteins and total solids showed good reduction during H2 production.
► Removal pattern of biomolecules with respect to VFA generation and pH variations on SHY was studied using surface plots.