Biohydrogen and biogas production from mashed and powdered vegetable residues by an enriched microflora in dark fermentation

This study conducted the utilization of vegetable residues by an enriched microflora inoculum to produce biohydrogen via anaerobic batch reactor. Dark fermentation processes were carried out with 3 kinds of vegetable residue substrates including broccoli (Brassica oleracea var. italica.), onion (Alium cepa Linn.), and sweet potato (Ipomoea batatas (L.) Lam). Vegetable wastes were pretreated into 2 forms, i.e. mashed and powdered vegetable, prior to the fermentation. The substrate used for the biohydrogen production were vegetable residues and inoculumat the vegetable residues/inoculum ratio of 1:1 (based on TS). The digestion processes were performedunder 120 rpm speed of shaking bottle in the incubator with control temperature of 35 degrees C. In thiswork, the maximum hydrogen production was achieved by anaerobic digestion at mashed onion with bioreactor inoculum that produced total hydrogen of 424.1 mL H-2 with hydrogen yield and hydrogen concentration of 151.67 mL H-2/g VSa(dded) and 43.54%, respectively. In addition, the hydrogen production continues took only 7 days for the vegetables blended with the bioreactor inoculum. Finally, it was found that the high potential of degradation of vegetable wastes an enriched microflora in dark fermentation also showed alternative solution to eliminate agricultural wastes to produce green energy. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study utilized enriched microflora to produce biohydrogen from vegetable residues through dark fermentation. Mashed onion substrate with bioreactor inoculum achieved the maximum hydrogen production within 7 days. The research suggests that utilizing enriched microflora for vegetable waste treatment is a potential pathway for green energy production.