The natural microbial consortium from many sources widely used for hydrogen production. Type of substrate and operating conditions applied on the biodigesters of the natural consortium used as inoculum impact the variation of species and number of microbes that induce biogas formation, so this study examined the effect of different inoculum source and its combination of biohydrogen production performance. The hydrogen producing bacteria from fruit waste digester (FW), cow dung digester (CD), and tofu waste digester (TW) enriched under strictly anaerobic conditions at 37OC. Inoculums from 3 different digesters (FW, CD, and TW) and its combination (FW-CD, CD-TW, FW-TW, and FW-CD-TW) were used to test the hydrogen production from melon waste with volatile solids (VS) concentration of 9.65 g/L, 37°C and initial pH 7.05 ± 0.05. The results showed that individual and combined inoculum produced the gas comprising hydrogen and carbon dioxide without any detectable methane. The highest cumulative hydrogen production of 743 mL (yield 207.56 mL/gVS) and 1,132 mL (yield 231.02 mL/gVS) was shown by FW and FW-CD-TW, respectively. Butyric, acetate, formic and propionic were the primary soluble metabolites produced by all the cultures, and the result proves that higher production of propionic acid can decrease hydrogen yield. Clostridium perfringens and Clostridium baratii prominently seen in all single and combination inoculum. Experimental evidence suggests that the inoculum from different biodigesters able to adapt well to the environmental conditions and the new substrate after a combination process as a result of metabolic flexibility derived from the microbial diversity in the community to produce hydrogen. Therefore, inoculum combination could be used as a strategy to improve systems for on-farm energy recovery from animal and plant waste to processing of food and municipal waste.Article History: Received February 5th 2018; Received in revised form May 7th 2018; Accepted June 2nd 2018; Available onlineHow to Cite This Article: Amekan, Y., Wangi, D.S.A.P., Cahyanto, M.N., Sarto and Widada, J. (2018) Effect of Different Inoculum Combination on Biohydrogen Production from Melon Fruit Waste. Int. Journal of Renewable Energy Development, 7(2), 101-109.https://doi.org/10.14710/ijred.7.2.101-10

An essential component in sustainable energy development is the production of bioenergy from waste. The most successful bioenergy technology worldwide is anaerobic digestion (AD), which is a microbially-mediated process of organic feedstock conversion into energy-rich compounds (volatile fatty acids (VFA) and biogas) for renewable energy generation. AD is deployed in a range of situations including systems for on-farm energy recovery from animal and plant waste to the processing of food and municipal solid waste (with the additional benefit of land-fill reduction).Anaerobic digesters rely on a diverse microbial community working syntrophycally through a series of interrelated biochemical processes.Each stage in anaerobic digestion is carried out by different microbial groups. Thus, to optimise energy recovery from the AD process, the microbial community must have stable performance over time, balancing the various metabolic functions and taxonomic community composition in digesters. Complicating this balance, it has been found that the presence of ammonia, sulphate, and hydrogen sulphide in substantial concentrations often cause failure in the AD process. Thus, these substances cause adverse shifts in microbial community composition and/or inhibit bacterial growth, that influencing AD performance.  ©2020. CBIORE-IJRED. All rights reserved

Biohydrogen (H2) production has the potential to provide clean, environmentally friendly, and cost-effective energy sources. The effect of increasing oxidative stress on biohydrogen production by acid-treated anaerobic digestion microbial communities was studied. The use of varying amounts of hydrogen peroxide (H2O2; 0.1, 0.2, and 0.4 mM) for enhancing hydrogen production from melon fruit waste was investigated. It was found that H2O2 amendment to the H2-producing mixed culture increased hydrogen production. Treatment with 0.4 mM H2O2 increased cumulative H2 output by 7.7% (954.6 mL/L), whereas treatment with 0.1 mM H2O2 enhanced H2 yield by 23.8% (228.2 mL/gVS) compared to the untreated control. All treatments showed a high H2 production rate when the pH was 4.5 – 7.0.  H2O2-treated samples exhibited greater resilience to pH reduction and maintained their H2 production rate as the system became more acidic during H2 fermentation. The application of H2O2 affected the volatile fatty acid (VFA) profile during biohydrogen fermentation, with an increase in acetic and propionic acid and a reduction in formic acid concentration. The H2O2 treatment positively affects H2 production and is proposed as an alternative way of improving H2 fermentation.

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