CAJ | 학술논문

【目的】研究海洋环境中产脂肪酶菌株的形态、生理生化特性及其所产胞外脂肪酶的酶学性质。【方法】以三丁酸甘油酯作为唯一碳源，利用平板涂布法从黄海胶州湾海泥中筛选到一株产脂肪酶的菌株，对其进行形态、生理生化和分子水平的鉴定，并对其产生的脂肪酶的部分酶学性质进行研究。【结果】产脂肪酶的菌株为薄壁芽孢杆菌属（Gracilibacillus）成员，命名为 Gracilibacillus sp．DN-X7。酶学性质研究表明：对该菌所产脂肪酶的最适作用温度、pH 和 NaCl 质量浓度分别为60℃、pH 9.0和30 g／L。稳定性试验表明，该酶具有良好的耐热、耐碱和盐稳定性。甘氨酸甜菜碱的存在能够显著提高酶的热稳定性，60℃保温30 min 酶活力仍保持46％以上。底物特异性试验结果表明 DN-X7菌株所产酯裂解酶是脂肪酶，能够分解不同种类的甘油酯和植物油。【结论】分离得到了一株能够产耐热、耐盐的碱性脂肪酶的海洋细菌。
【목적】연구해양배경중산지방매균주적형태、생리생화특성급기소산포외지방매적매학성질。【방법】이삼정산감유지작위유일탄원，이용평판도포법종황해효주만해니중사선도일주산지방매적균주，대기진행형태、생리생화화분자수평적감정，병대기산생적지방매적부분매학성질진행연구。【결과】산지방매적균주위박벽아포간균속（Gracilibacillus）성원，명명위 Gracilibacillus sp．DN-X7。매학성질연구표명：대해균소산지방매적최괄작용온도、pH 화 NaCl 질량농도분별위60℃、pH 9.0화30 g／L。은정성시험표명，해매구유량호적내열、내감화염은정성。감안산첨채감적존재능구현저제고매적열은정성，60℃보온30 min 매활력잉보지46％이상。저물특이성시험결과표명 DN-X7균주소산지렬해매시지방매，능구분해불동충류적감유지화식물유。【결론】분리득도료일주능구산내열、내염적감성지방매적해양세균。
Abstrzct:[Objective]A marine-derived bacteria producing extracellular lipase was isolated and i-dentified.The enzymatic properties of the bacteria-produced lipases were characterized.[Method]In this study,tributyrin was used as the sole carbon source.Serial dilution technique was used to isolate microorganisms from marine sediment samples in Jiaozhou Bay of the Yellow Sea on solid agar plates.One of the isolates which produce the highest level of lipase was identified based on morphological,physio-biochemical characteristics and 16S rRNA gene sequence analysis.Moreo-ver,some enzymatic properties of the bacteria-produced lipases were characterized.[Results]The marine-derived bacterium which produce extracellular lipase belonged to Gracilibacillus genus and was designated as Gracilibacillus sp.DN-X7.The result of enzymatic properties showed that the optimal temperature,pH and NaCl concentration of producing lipases were 60 ℃,9.0 and 3%, respectively.The enzyme was adapted to high temperature (<50 ℃),alkaline condition (7.0 -12.0)and a wide range of NaCl concentrations.Addition of glycine betaine significantly improved the themostability of the enzyme.The enzyme retained more than 50% of its maximum activity after 1 h at 60 ℃ in the presence of glycine betaine.Tests of substrate specificity revealed that it was lipase,rather than esterase.The lipase can hydrolyze different kinds of triglycerides and plant oil.[Conclusion]A bacterium that can produce salt-tolerant,thermostable and alkaline li-pases was isolated.