Ethanol fermentation on seeds of seagrass Zostera marina was studied. The seeds were collected from the annual plant colony of Z. marina at Hinase Bay, Okayama. The seeds contained 83.5% carbohydrates including 48.1% crude starch on a dry weight basis, which is comparable to cereals such as wheat flour and corns. The seeds were saccharified with glucoamylase (50°C, 96 h) and 103.4 g/l concentration of glucose juice was obtained. The glucose juice was further fermented (23°C-35°C, 15 days) with Saccharomyces cerevisiae strains NBRC10217(T) and Kyokai 7-go, and ethanol was obtained at a 65.0 g/l (82.3 ml/l) level by monographic double-fermentation and at a 130.4 g/l (165.1 ml/l) level by parallel double-fermentation. Fermented products of seagrass seeds containing such a high ethanol concentration as the present study have potential to be utilized not only for biofuel but also for foods and beverages in the future. Culturing of seagrass seeds as a crop may enable development of a new marine fermentation industry.
Keywords: Aquatic bioresources; Ethanol fermentation; Saccharomyces cerevisiae; Seagrass seed; Zostera marina.
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