Abstract
This experiment was carried out to elucidate the thermotolerant properties of a thermophilic bacterium which isolated from soils of the hot springs area and selected for the $\beta$-galactosidase production. Biochemical and physiological characteristics of this strain were studied, including the investigation on the fatty acid composition for its neutral fats. The results obtained were summarized as follows. 1. This bacterium was identified as a strain belong to the genus Thermus. 2. Optimal temperature and pH for growth of this strain were $65^{\circ}C$ and pH 6.5 respectively, and it was found to be an absolute thermophilic bacterium which could not grow at 37$^{\circ}C$. 3. No growth was obtained in the medium which contained more than 1.0% of sodium chloride. 4. The tolerable concentration of antobiotics were 10$\mu\textrm{g}$ of penicillin G per $m\ell$ of medium and 0.5$\mu\textrm{g}$ of chloramphenicol per $m\ell$ respectively 5. This strain had autotrophilic requirements for calcium-pantothenate and pyridoxine-HCO as an-essential factor and for niacin as a stimulative factor. 6. Fatty acid composition of neutral fats of the strain was palmitic acid. 60.20%; lauric acid, 11.8%; myristic acid, 7.56%, behenic acid, 4.25%; capric acid, 1.77%; stearic acid, 2.13%; arachidic acid, 1.53%; and others unidentified, 10.7%.
고온균의 생리적 특성자 내열기구에 관한 기초 자료를 얻고자 온천토양에서 $\beta$-galactosidase를 생산하는 고온균을 분리하여 동정하고 몇가지 주요한 생리적 특성을 검토하였으며 그의 균체 지방산 조성을 gas chromatography로 분석하여 다음과 같은 결과를 얻었다. 1. $\beta$-galactosidase를 생산하는 공시균주는 Thermus sp. 으로 동정되었다. 2. 분리선정한 균주의 최적 생육온도는 $65^{\circ}C$이었고, 37$^{\circ}C$에서 생육하지 않는 절대고온균 이었으며 최적pH는 6.5내외이었고 pH에 민감하였다. 3. NaCl에 대한 내성은 NaCl 1% 이상에서는 생육하지 못했다. 4. 항생물질에 대한 내성은 penicillin G는 10$\mu\textrm{g}$/$m\ell$, chloramphenicol은 0.5$\mu\textrm{g}$/$m\ell$ 이었다. 5. Vitamin 요구성은 Ca-pantothenate와 pyridoxine-HCI를 절대적 생육인자로 요구하였고niacin을 자극적 생육인자로 요구하였다. 6. 공시균주의 균체 지방산 조성은 palmitic acid 60.20%, lauric acid 11.80%, myristic acid 7.56%. behenic acid 4.25%, Capric acid 1.77%, stearic acid 2.13%, arachidic acid 1.53% 이었다.