| Summary: | Three novel hydrogen-generating strains, ST1, ST4, and ST5, were isolated from the rumen of cow in Vietnam, and respectively identified as <em>Clostridium beijerinckii</em> ST1, <em>Clostridium bifermentans</em> ST4, and <em>Clostridium butyricum</em> ST5, based on 16S rDNA gene sequence analysis and physiobiochemical characteristics. The dark fermentative hydrogen production of these isolated <em>Clostridium</em> strains was performed and characterized in both pure- and co-cultures from various carbon sources including sucrose, glucose, lactose, xylose, molasses, cassava stumps, and rice distillers wet grains with soluble. The highest hydrogen production was achieved from a co-culture with three <em>Clostridium</em> strains. To optimize the operational conditions of temperature, time, and substrate concentration for the high-level production of hydrogen, response surface methodology in a Box-Behnken design was used. The results revealed a maximum hydrogen production of 1.13 ± 0.015 L H<sub>2</sub>/L medium by the three-strain co-culture under the following fermentation conditions: 11.63 g/L sucrose, 36.1 °C, in 51.13 h.
|
|---|