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The waste product from salted Undaria pinnatifida (sea mustard) processing was fermented to produce bioethanol by Saccharomyces cerevisiae KCCM 1129 at laboratory and pilot development unit (PDU) scales. Thermal acidic hydrolysis of salted U. pinnatifida was conducted with 75 mM HSO at 121℃ for 60 min and the addition of 1.4 KNU/mL Termamyl 120L. A total monosaccharide concentration of 19.3 g/L and 32.2% conversion from 59.9 g/L total carbohydrate using 130 g dw/L salted U. pinnatifida were achieved. Ethanol fermentations in 5 and 500 L fermenters were carried out to produce 8.5 g/L of ethanol with an ethanol yield (Y) of 0.44 at 24 h and 7.9 g/L with Y of 0.41 at 18 h, respectively. The fermentation time of the PDU-scale reaction was reduced due to differences in the impeller type and geometry of the fermenters. [ABSTRACT FROM AUTHOR]

Seaweed resources can be used as raw materials to produce bioethanol, a renewable biofuel, to overcome fossil fuel depletion and environmental problems. Red seaweeds possess high amount of bioethanol-producible carbohydrates. Among 55 species tested, the carrageenophyte Kappaphycus alvarezii (also known as cottonii) was selected as the best resource for bioethanol production. This species is one of the most abundant and easily cultured red seaweeds. The main components of carrageenan are d-galactose-4-sulfate and 3,6-anhydro- d-galactose-2-sulfate, which are potentially fermentable d-typed carbohydrates. The seaweed powder was hydrolyzed with 0.2 M sulfuric acid and fermented with brewer's yeast. The ethanol yield from the K. alvarezii hydrolysate was 0.21 g g-galactose, which corresponded to a 41% theoretical yield. It revealed a relative ethanol production of 66% comparing to that of pure galactose. [ABSTRACT FROM AUTHOR]