초록
To achieve more stable bio-hydrogen (bioH<SUB>2</SUB>) production from non-food feedstocks, stable feedstock preparations of marine biomass and an efficient bioH<SUB>2</SUB> system using marine bacteria under saline conditions are two important key technologies that needed to be developed. Vibrio tritonius strain AM2, which was isolated from the gut of a marine invertebrate, was cultured under various conditions in marine broth (at initial 2.25% (w/v) NaCl) supplemented with mannitol, a seaweed carbohydrate, to evaluate its hydrogen production. The maximum molar yield of bioH<SUB>2</SUB> was recorded as 1.7 mol H<SUB>2</SUB>/mol mannitol at pH 6 and 37 <SUP>o</SUP>C. The mannitol-grown cells had higher yields of bioH<SUB>2</SUB> than the glucose-grown cells in the pH range 5.5-7.5. Compared to glucose, mannitol might be a better substrate for bioH<SUB>2</SUB> production using strain AM2. Fermentation product profiling revealed that strain AM2 might be utilising the formate-hydrogen pathway for bioH<SUB>2</SUB> production. Furthermore, strain AM2 was able to produce hydrogen from powdered brown macroalgae containing 31.1% dry weight of mannitol. The molar yield of hydrogen reached 1.6 mol H<SUB>2</SUB>/mol mannitol contained in the seaweed feedstock. In conclusion, strain AM2 has the ability to produce hydrogen from mannitol with high yields even under saline conditions.