近江牡蛎肠道细菌及其产酶能力

从近江牡蛎肠道中分离出21株菌,其中, 9株为革兰阳性菌, 12株革兰阴性菌。为寻找能分泌多种酶的有益微生物,研究了它们蛋白酶、脂肪酶、淀粉酶、纤维素酶的产酶能力。结果表明,有61 .9%的菌株能分泌蛋白酶或淀粉酶(各有13株菌);有52. 4%的菌株能分泌脂肪酶(11株菌);有33. 3%的菌株能产纤维素酶(7株菌)。在这21株菌中,产4种酶的有5株菌,产3种酶的3株菌,产两种酶的5株菌,产1种酶的3株菌,不产酶的仅有5株菌。不产酶的菌株仅占细菌总数的23. 8%,而各种产酶菌则高达76. 2%,由此表明细菌在近江牡蛎对食饵消化过程的重要性。

Bacteria Isolated from Intestine of Ostrea vivularis Gould and Their Zymogenicities

To understand the role(s) of bacteria from the oyster intestine in the digestion of food and assimilation of nutrients, and to screen for the potentially beneficial strains for the future applications in the oyster farming industry, bacteria from Ostrea vivularis Gould intestine were isolated and their enzymeproducing capabilities were studied. In total, 21 strains of bacteria were isolated and Gram stain showed that 9 strains are Gram-positive while 12 are Gram negative. Casein, olive oil, starch and CMC were used as substrates for screening protease, lipase, amylase and cellulase respectively. Results showed that 61.9% of the intestinal bacterial strains were able to produce extracellularlly either protease or amylase (13 strains each), 52.4% of the strains were able to produce lipase (11 strains), and 33.3% of the strains capable of producing cellulase (7 strains). Among the 21 isolates, 5 were showed to produce all four enzymes, 3 three enzymes, 5 two enzymes, 3 one enzyme and only 5 isolates no enzymes detected at all. In other words, 76.2% (16/21) of the isolates were capable of producing enzymes whereas only 23.8% (5/21) of isolates were not being able to produce these four enzymes. Therefore, it can be concluded that bacteria in the intestine of Ostrea vivularis Gould play an important role in the digestion of food.