(175h) High Production of Butyric Acid through Simultaneous Utilization of Mannitol and Sugars from Macroalgae and Rice Straw

Recently, biological production of butyric acid has been investigated using renewable biomass because of fossil fuel depletion. Seaweed biomass is a great potential feedstock for biochemical and biofuel production. C. tyrobutyricum ATCC 25755 was chosen among the tested 13 different Clostridium strains for butyric acid production from mannitol, a dominant carbohydrate in Saccharina japonica hydrolysate. When 0.5 ~ 2% (w/v) H₂SO₄ was used for S. japonica hydrolysate preparation, 1.5% acid-treated hydrolysate was more effective in butyric acid production than the other hydrolysates. Notably, the consumption of mannitol actively occurred only when acetic acid was present during the fermentation. By mixing S. japonica and rice straw to take advantage of glucose and acetic acid in rice straw, C. tyrobutyricum ATCC 25755 effectively consumed mannitol by utilizing acetic acid in hydrolysate and acetic acid derived from glucose with the enhanced butyric acid production. The results demonstrate the potential of butyric acid production from mixed biomass of macroalgae/lignocellulose overcoming the drawbacks of using single biomass.