| dc.description.abstract | Biohydrogen as gas produced from the activity of microorganisms is an environmentally friendly alternative energy because the production process does not require large energy and combustion results only in the form of water vapor and heat without producing waste that can pollute the environment. This research aims to produce H2 through fermentation with sweet sorghum (Sorghum bicolor (L.) Moench) as a main substrate using Enterobacter aerogenes ADH-43 in continuous mode at packed bed bioreactor. This research was conducted by the anaerobic fermenting E. aerogenes ADH-43 in medium containing about 4.27% total sugar in the anaerobic packed bed reactor that was operated in batch mode at first stage to find the value of specific growth rate of cells which was them used to determine the dilution rate (D). Dilution rates tested in this study were: D = 0.10, 0.15 and 0.20/ h. During fermentation the temperature was controlled at 37 ± 1oC. Cultivation were carried out until steady state in which the amount of H2 produced, pH, and OD (optical density) were constant. Fermentation at each D was carried out with three replications. Observations and analysis were done by measuring pH, OD, cell dry weight, total sugar, reducing sugar content, organic acid content and the amount of gas. In batch mode, H2 flow rate obtained was 8.26 L H2/L substrate and yield of 3.79 mol H2/ mol total sugar, whereas in continuous mode D = 0.15/ h was found to be optimum with a yield of 0.67 mol H2/ mol total sugar and H2 production of 10.56 ml H2/ min (1.41 L H2/ L h; 62.84 mmol / L h). As a comparison using molases as a main substrate, D=0,15/ h produced a smaller yield of 0.46 mol H2/ mol total sugar and H2 production was 7.79 ml H2/ min (1.04 L H2/ L h and 46.42 mmol H2/ L h). | en |
