Abstract: With used molasses as substrate, this paper studied its zymolytic characteristics by a novel hydrogen-producing strain Ethanoligenens sp. B49, and the effects of nitrogen nutritional condition on the hydrogen yield. The results showed that B49 could use molasses as the substrate for its cell growth when the COD was within the range of 10.3-20.6 g·L^-1, and the cell growth rate and hydrogen yield increased with increasing COD. When the COD of molasses was above 20.6 g·L^-1, the growth of Ethanoligenens sp. B49 was limited , and the hydrogen yield was decreased gradually with increasing COD. When the COD of molasses was up to 41.2 g·L^-1, cell growth was restrained. The feasible COD of molasses for Ethanoligenens sp. B49 was 20.6 g·L^-1, and the addition of organic nitrogen could significantly increase the hydrogen production by Ethanoligenens sp. B49 via molasses fermentation. The effect of added organic nitrogen was decreased in the order of yeast extract>beef extract>peptone>carbamide, and the optimal concentration of yeast extract for B49 growth and hydrogen yield was 4 g·L^-1. At the optimal concentrations of molasses and yeast extract, the hydrogen yield was increased from 44.82 mmol·L^-1 to 78.97 mmol·L^-1, with an increment of 76.2%.

Key words: Tree ring, Atmosphere, ¹³C, Model