title: Effect of temperature and temperature shock on the stability of continuous cellulosic-hydrogen fermentation.
abstract: Three continuous stirred tank reactors (CSTR) were operated under mesophilic (37 ± 1°C), thermophilic (55 ± 1°C) and hyper-thermophilic (80 ± 1°C) temperatures for 164 days to investigate the effect of temperature and temperature shock on the cellulosic-dark hydrogen fermentation by mixed microflora. During steady state condition, the sudden decreases in the fermentation temperature occurred twice in each condition for 24h. The results show that the 55 ± 1 and 80 ± 1°C presented stable hydrogen yields of 12.28 and 9.72 mmol/g cellulose, respectively. However, the 37 ± 1°C presented low hydrogen yield of 3.56 mmol/g cellulose and methane yield of 5.4 mmol/g cellulose. The reactor performance under 55 ± 1 or 80 ± 1°C appeared to be more resilient to the sudden decreases in the fermentation temperature than 37 ± 1°C. The experimental analysis results indicated that the changing in soluble by-products could explain the effect of temperature and temperature shock, and the thermophilic temperature is expected having a better economic performance for cellulosic-hydrogen fermentation.
authors.affiliation: Department of Environmental Science, Graduate School of Environmental Studies, Tohoku University, Aoba-ku, Sendai 9808579, Japan.
authors.forename: Samir I
authors.initials: SI
authors.lastname: Gadow
authors.forename: Hongyu
authors.initials: H
authors.lastname: Jiang
authors.forename: Ryoya
authors.initials: R
authors.lastname: Watanabe
authors.forename: Yu-You
authors.initials: YY
authors.lastname: Li
mesh_terms: D057919:Biological Oxygen Demand Analysis; D002482:Cellulose / Q000737:chemistry*; D005285:Fermentation; D006859:Hydrogen / Q000737:chemistry*; D013696:Temperature
chemical_list: D006859:Hydrogen; D002482:Cellulose
keywords: Bio-hydrogen; Cellulose; Continuous mode; Dark fermentation; Temperature shock