Abstract :
[en] Utilization of dragon fruit (Hylocereus spp.) branch – a natural source accessible in great quantity, in biogas production targets not only to fulfill the enhancing demands for green energy but also to increase waste valorization as well as to improve the added-value of this fruit. However, there is a lack of research on the promising biogas production from this component. Thus, this study was aimed to employ the biochemical methane potential tests to analyze the optimized ratio between branches and pig dung (0, 25, 50, 75, and 100%), ratio between feedstock and inoculum (1:1, 1:1.5, 1:2, and 1:2.5 g/mL), ratio between solid mixture and water (1:1, 1:2, 1:3, 1:4, 1:5, and 1:6 g/mL), percentage of added seedings (0, 10, 20, and 30%), and incubating temperature (27, 35, and 50oC) for effective methane production. For all the mixtures of plant components, dungs, inoculum, seeding, and water, biogas productivity tended to intensify considerably in the first eight to fourteen days, culminated at peak during operating duration, and then began to diminish promptly in the next following days. Sole dragon fruit branches were fermented for 22 days until biogas yield was less than 1%, while sole manure and the mixtures of plant components and dungs were anaerobically digested for 17 to 21 days. The appropriate ratio between dragon fruit branches and pig dung, feedstock and inoculum, solid mixture and water, percentage of added seedings, and incubating temperature were 50% for dragon fruit branches and 50% pig dung, 1:2 g feedstock/mL inoculum, 1:5 g solid mixture/mL water, 20% added seedings, and around 27oC, respectively. At these optimized conditions, the accumulative biogas concentration was 2628 mL after 22 working days. To sum up, dragon fruit branches are potential for biogas production, and the optimal conditions could be used for further bigger model or pilot plant
