There have been many kinds of fermentation technology and products since ancient times. For example, fermented food items from soybean are common in the East Asian countries of China, Korea and Japan, while those from fish are common in Southeast Asian countries 5 . Despite the long history of fermentation technology, fermented food items produced from algae have yet to be developed (Fig. 1). Many studies were conducted on methane fermentation of seaweeds during the 1970s and 1980s 1, 2, 6 . However, methane fermentation is a technology for supplying energy, not for foods and food production.Macroalgae (macrophytes) can be divided into four groups: brown algae (Phaeophyta), red algae (Rhodophyta), green algae (Chlorophyta), and seagrass (Magnoliophyta). Carbohydrates are the major component of seaweeds and seagrass (ca. 50-70% on a dry basis) 11,29 , containing mostly polysaccharides to construct algal tissue. For example, brown algae contain alginate and fucoidan as major components. Red algae contain galactan (e.g. agar, carrageenan) as a major component. Green algae and seagrasses contain cellulose and hemicellulose as major components. These major algal polysaccharides are known to be unfavorable substrates for fermentation. This may be one of the reasons why algal fermentation technology has yet to be developed. However, it was recently reported that seaweed could be used as a substrate for lactic acid and ethanol fermentation, provided that the algal tissue was saccharified with cellulase enzymes. This finding opened the possibility of obtaining foods and related items from algal fermentation 17,18,19 . This manuscript reviews past studies on the lactic acid fermentation of algae 17,22 . It also refers to other kinds of algal fermentation that are now being developed, such AbstractMany kinds of fermented products are now being consumed as food and dietary items, although those produced from algae have yet to be developed. A recent observation that seaweed could be used as a substrate for lactic acid fermentation opened the possibility of obtaining such products as foods, diets and fertilizers by algal fermentation. This manuscript reviews past studies on the lactic acid fermentation of algae. Both macroalgae (seaweeds) and microalgae can be used as the materials for lactic acid fermentation, as successful fermentation has been observed regarding all the seaweed species tested to date. Saccharification by cellulase treatment is considered a significant element for inducing algal fermentation. The addition of a starter culture of lactic acid bacteria and salt also promotes successful fermentation. A wide range of Lactobacillus species can be used for inducing algal fermentation, with Lactobacillus brevis, Lactobacillus casei and Lactobacillus plantarum in particular showing a superior ability to dominate in seaweed fermentation cultures. A starter culture of halophilic lactic acid bacteria that is now being developed will make it possible to prepare algal fermented products containing a high (>10%) salt con...

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The effects of soy sauce koji and the lactic acid bacterium, Tetragenococcus halophilus , were studied on the fermentation of fish sauce prepared from Chinese silver carp. The fish sauce prepared without koji and the lactic acid bacterium contained low levels of organic materials, total nitrogen, and organic acids. The use of koji was effective in increasing these qualitative parameters and further improved the amino acid score of the fish sauce. Addition of T. halophilus had an effect on lowering the pH value during the initial period of fermentation when the soy sauce koji was also supplemented. In contrast, T. halophilus -like bacteria were found to be predominant for all tanks fermented under the different starting conditions. Although it was not examined whether the T. halophilus -like bacteria observed after fermentation were the same as the starter-bacterium or not, it was suggested that T. halophilus plays an important role in the successful fermentation of silver carp fish sauce. Sensory evaluation conducted with Japanese and Chinese panelists also suggested the superiority of the use of koji for fermentation of silver carp fish sauce.

This is the first report of lactic acid and ethanol fermentation in seaweed, which is expected to provide a new material for food and dietary applications.

Japanese eating habits are characterized by the consumption of various food materials such as cereals, vegetables, fish, shellfish, marine algae and meat. Therefore, properties of functional substances in food materials may be enhanced or lessened by the combination of various food materials. In the present study, we examined how the combination of wakame and fish containing polyunsaturated fatty acids, which are typical Japanese food materials, affected rat lipid metabolism. Rats were fed one of four diets [control diet (C), AIN-76 diet with 5 g/100 g rapeseed oil; wakame diet (W) containing 19.1 g/100 g Undaria pinnatifida (wakame) dried powder in the C diet; fish oil diet (FO), AIN-76 diet with 4.1 g/100 g fish oil; wakame-fish oil diet (W + FO), the FO diet containing 19.1 g/100 g dried wakame powder] for 4 wk. We measured the concentration of lipids in serum and liver and hepatic activities of enzymes involved in fatty acid metabolism. The W diet, FO diet and W + FO diet significantly reduced the concentration of triacylglycerols in the serum and liver compared with the C diet. This decrease in the concentration of hepatic triacylglycerol was greatest in rats fed the W + FO diet. The activity of glucose-6-phosphate dehydrogenase, which is involved in fatty acid synthesis in the liver, of rats fed the W, FO and W + FO diets was lower than that in rats fed the C diet. However, the activities of malic enzyme and fatty acid synthetase did not differ among the four groups. In contrast, the W diet and W + FO diet increased the serum concentration of beta-hydroxybutyrate. Further, the activity of 3-hydroxyacyl-CoA dehydrogenase, which is involved in fatty acid beta-oxidation in the liver, was greater in rats fed the W diet (42%), the FO diet (154%) and the W + FO diet (381%) than in those fed the C diet. Because the decrease in the concentration of triacylglycerol in the liver was greatest when rats were fed wakame and fish oil at the same time (W + FO diet), we conclude that there was a synergistic process affecting fatty acid beta-oxidation in the liver. These results suggest that the simultaneous consumption of fish (fish oil) and wakame decreases the concentration of triacylglycerol in the serum and liver.