Study on Hydrogen Production Potential Utilizing Leachate from Aerobic Bio-Leaching Bed Fed with Napiergrass and Kitchen Waste

Abstract Cellulose hydrolysis is rate-limiting step in bioprocess and a long hydraulic retention time is necessary for microbial digestion in anaerobic digester. Solid-State fermentation is suitable for fungi growth and can accumulate cellulolytic enzymes. Accordingly, a total working volume of 90-L with 5-layers aerobic bio-leaching bed(ABLB) which introduced aerobic fungi and bacteria was adopted to facilitate the hydrolysis of napiergrass and hydrogen production potential was evaluated in this study. Napiergrass was chopped into 1∼2 cm and mixed with kitchenwaste, compost as nutrient supplement and inoculum respectively. The crisscrossed mixture was packed and pH controlled tap water was flowed through each layer. One through leaching was performed in the 1 st Run, and the contact time of leachate with biomass was 2.2 hr. Cellulose conversion efficiency was 27%. As the contact time increased to 21hr in 2 nd Run, cellulose conversion efficiency also improved to 50%. In order to increase the contact time, leachate was recirculated for 7 days in 3 rd Run. At a contact time of 212 hr, 66% cellulose conversion efficiency was achieved. The residue and the leachate after ABLB treatment revealed improvement of hydrogen production potential in subsequent batch test. DGGE fingerprint showed Candia , Fusarium , Aspergillus were sustained in the reactor.