Isolation of Keratanase-Producing Bacteria from Natural Habitats

A study was undertaken to isolate new strains of bacteria that produce keratan sulfate-hydrolyzing endoglycosidase (keratanase) at reasonable high rate in usual culture medium. Firstly, screening was made on all the bacteria capable of growing on the synthetic medium containing keratan sulfate as the sole carbon source, and 658 isolates were thus obtained from marine, freshwater and land environments in Japan. These isolates were cultured in keratan sulfate-containing peptone medium, and the cultures obtained were assayed for keratanase activity. Out of 658 isolates, only 22 isolates were found to produce appreciable amounts of keratanase in the presence of keratan sulfate. The chosen bacteria were transferred to the peptone medium without any supply of keratan sulfate, and the cultures obtained were then assayed for keratanase activity. It was found that in the absence of keratan sulfate some bacteria produced more whereas others produced less keratanase. Strain no. F-179 from Flavobacterium sp. possessed the highest productivity of keratanase among all the isolates. Finally, the keratanase from strain no. F-179 was purified, and its enzymatic properties were examined. It was concluded that this organism may be a good source of keratanase

Isolation of Keratanase-Producing Bacteria from Natural Habitats

A study was undertaken to isolate new strains of bacteria that produce keratan sulfate-hydrolyzing endoglycosidase (keratanase) at reasonable high rate in usual culture medium. Firstly, screening was made on all the bacteria capable of growing on the synthetic medium containing keratan sulfate as the sole carbon source, and 658 isolates were thus obtained from marine, freshwater and land environments in Japan. These isolates were cultured in keratan sulfate-containing peptone medium, and the cultures obtained were assayed for keratanase activity. Out of 658 isolates, only 22 isolates were found to produce appreciable amounts of keratanase in the presence of keratan sulfate. The chosen bacteria were transferred to the peptone medium without any supply of keratan sulfate, and the cultures obtained were then assayed for keratanase activity. It was found that in the absence of keratan sulfate some bacteria produced more whereas others produced less keratanase. Strain no. F-179 from Flavobacterium sp. possessed the highest productivity of keratanase among all the isolates. Finally, the keratanase from strain no. F-179 was purified, and its enzymatic properties were examined. It was concluded that this organism may be a good source of keratanase

白蓮の練り製品化

A test for the utilization of silver carp as a raw material of fish sausage products has been carried out. The results obtained are as follows: (1) The recovery yield from silver carp to frozen surimi was 25%. Bleaching with 0.1% sodium citrate and then with 0.1% CaCl_2 was shown to be effective in increasing gel strength of the surimi. No significant protein denatured was observed during the storage of the surimi at -20℃ for at least 3 months. (2) The quality ranked second to the walleye pollack surimi, based on gel strength, coler, press moisture and so on. (3) The greatest gel strength (2255g･cm)of silver carp surimi was obtained at 60℃ at which the walleye pollack surimi usually shows the lowest gel strength. However, the maximal gel strength (2331g･cm)was obtained by two step heating (setting at 40℃ for 30 min and then heating at 90℃ for 30 min). (4) Silver carp surimi was proved to be a potential raw material for fish sausage products.白蓮を原料として冷凍すり身を作るための諸条件及びすり身の諸性質について,検討した.1.-20℃貯蔵中,白蓮すり身ゼリー強度の急激な低下は認められなかった.2.白蓮すり身の品質はスケトウダラすり身の2級品に相当すると判断された.3.白蓮すり身の加熱によるゲル形成能はスケトウダラすり身と著しく異なり,一段加熱では60℃加熱が最も高いゼリー強度(2255g･cm)を示し,二段加熱では,40℃で坐らせたすり身が最大ゼリー強度(2331g･cm)に達した.また,白蓮は坐りにくく戻りにくい魚種に分類された.4.白蓮は魚肉ソーセージの原料として利用可能と判断された

A Test for the Utilization of Silver Carp as a Raw Material of Fish Sausage Products

A test for the utilization of silver carp as a raw material of fish sausage products has been carried out. The results obtained are as follows: (1) The recovery yield from silver carp to frozen surimi was 25%. Bleaching with 0.1% sodium citrate and then with 0.1% CaCl_2 was shown to be effective in increasing gel strength of the surimi. No significant protein denatured was observed during the storage of the surimi at -20℃ for at least 3 months. (2) The quality ranked second to the walleye pollack surimi, based on gel strength, coler, press moisture and so on. (3) The greatest gel strength (2255g･cm)of silver carp surimi was obtained at 60℃ at which the walleye pollack surimi usually shows the lowest gel strength. However, the maximal gel strength (2331g･cm)was obtained by two step heating (setting at 40℃ for 30 min and then heating at 90℃ for 30 min). (4) Silver carp surimi was proved to be a potential raw material for fish sausage products.白蓮を原料として冷凍すり身を作るための諸条件及びすり身の諸性質について,検討した.1.-20℃貯蔵中,白蓮すり身ゼリー強度の急激な低下は認められなかった.2.白蓮すり身の品質はスケトウダラすり身の2級品に相当すると判断された.3.白蓮すり身の加熱によるゲル形成能はスケトウダラすり身と著しく異なり,一段加熱では60℃加熱が最も高いゼリー強度(2255g･cm)を示し,二段加熱では,40℃で坐らせたすり身が最大ゼリー強度(2331g･cm)に達した.また,白蓮は坐りにくく戻りにくい魚種に分類された.4.白蓮は魚肉ソーセージの原料として利用可能と判断された