Kenji Sakaguchi

Betaine as a Growth Factor for Pediococcus soyae

Besides P-factor, Pediococcus soyae requires betaine (glycine-betaine) as a specific growth promotant. The maximal growth is obtained with the supplementation of both betaine and P-factor to the synthetic medium, while betaine only gives the half-maximal growth. When the organism is cultured in 18% salted media, the addition of both betaine and P-factor is essential for the occurrence of growth. Thus, betaine is requisite for Ped. soyae as a growth promoting factor and also as a factor bestowing the osmotelerant ability.

Studies on the Activities of Bacteria in Soy Sauce Brewing: Part V. The Effects of Aspergillus sojae, Pediococcus soyae, Bacillus subtilis and Saccharomyces rouxii in Purely Cultured Soy Sauce Brewing

The soy koji mold Aspergillus sojae is purely cultured on the materials of soy koji, and soaked in the sterile concentrated sodium chloride solution (26%). To it, Ped. soyae and Sacch. rouxii are aseptically inoculated and their roles playing in soy sauce brewing are examined. Bacillus subtilis is added in the form of wheat bran culture into the purely cultured soy mash and its influencies are observed.The appropriate addition of the bran culture of Bac. subtilis favors for the development of necessary aroma, and eliminates the polypeptide-like turbidity in soy sauce. The growth of Ped. soyae in soy mash stimulates the formation of organic acids, and makes the mash acidic which is necessary for the sound fermentation, removes undesirable flavors, and adds the indispensable good flavors for soy sauce. But the rapid lowering of pH results in the depression of Aspergillus Alkaline Proteinase activities, followed by its inactivation, thus the percentage of solubilization of the protein material decreases. The...

Studies on the Activities of Bacteria in Soy Sauce Brewing:Part IV. Proteases, Transaminases of Pediococcus soyae , nov. sp., and its Numerical Transition in Soy Mash

The extracellular proteinase and peptidase of Pediococcus soyae is not found in its growing culture solution and culture filtrate. In the cell extract, weak activities of proteinase and peptidase are observed.Weak transaminase and reductive amination activities of producing glutamic acid from α-keto-glutaric acid are estimated in the resting cell suspension and also in the crude cell extract. The potent amino group doners are; alanine, leucine, lysine, aspartic acid and ammonium chloride.Starch fermentation by Ped. soyae strain d6 is confirmed.The numbers of lactic acid bacteria in soy koji are about 0.1–3 billion per gram and are much numerous than aerobic spore forming bacteria. The majority of them are salt sensitive Streptococci and Lactobacilli, but fewer salt tolerant Pediococcus soyae also exist. In the soy mash, salt sensitive lactic acid bacteria decrease rapidly within a period of two months. On the contrary, Ped. soyae grows well in the 18% salted mash, starting at 102–108/ml, reaching to 108–1...

Growth of Pediococcus soyae nov. sp. in Highly Concentrated Solutions of Inorganic Salts and Sugars: Studies on the Activities of Bacteria in Soy Sauce Brewing. Part VI

Pediococcus soyae nov. sp., which has an inherited salt tolerant nature, is grown in solutions of high osmotic pressure. When this strain is transferred from 0.5% salted medium to a new medium containing 18% sodium chloride, the viable counts of this organism firstly decrease from about one half to one-third of the inoculated cells, and then normal growth occurs. This indicates the occurrence of physiological adaptation at an early stage of growth.The growth of this lactic acid bacterium is observed in concentrated solutions of various inorganic salts. The solutions containing Na+, K+, Cl−, NO3− and SO4– – ions are not toxic for the organism, and the organism can grow in solutions of 133 atm. osmotic pressure, generally. However, Li+, Ca++, Mg++ and Br+ are, toxic for growth.In concentrated sugar solutions, this organism also propagates well, and growth is observed in the media containing 50% glucose or 60% sucrose, osmotic pressure being 105 and 84 atm., respectively. Therefore, Pediococcus soyae nov. sp...