Abstract
This experiment was carried out to elucidate the thermotolerant properties of a thermophilic bacterium which was isolated from soils of the hot springs area and selected for the ${\beta}$-galactosidase production. This bacterium was identified as a strain belong to the genus Thermus. Biochemical and physiological characteristics of this strain were studied, including the investigation of the fatty acid composition of its neutral fats. The results obtained were summarized as follows. 1. 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 the temperature below $43^{\circ}C$. 2. No growth was obtained in the medium which contained more than 1.0% of sodium chloride. 3. The tolerable concentration of antibiotics were 10mg of penicillin G per ml of medium and 0.5mg of chloramphenicol per ml respectively. 4. This strain had auxotrophilic requirements for calcium-pantothenate and pyridoxin-HCl as an essential factor and for niacin as a stimulative factor. 5. Yellow pigment was released into the liquid culture of this strain, which showed maximum absorption at 420 nm. 6. Fatty acid composition of neutral fats of the strain was 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%; and others unidentified, 10.7%.
고온균(高溫菌)의 생리적(生理的) 특성(特性)과 내열기구(耐熱機構)에 관한 기초자료(基礎資料)를 얻고자 온천토양(溫泉土壤)에서 ${\beta}$-galactosidase를 생산(生産)하는 고온균(高溫菌)을 분리(分離)하여 동정(同定)하고, 몇가지 주요(主要)한 생리적(生理的) 특성(特性)을 검토(檢討)하였으며, 그의 균체지방산(菌體脂肪酸) 조성(組成)을 gas chromatography로 분석(分析)하여 다음과 같은 결과(結果)를 얻었다. 1. ${\beta}$-galactosidase를 생산(生産)하는 공시(供試) 균주(菌株)는 Thermus속(屬)으로 동정(同定)되었다. 2. 분리선정(分離選定)한 균주(菌株)의 최적(最適) 생육온도(生育溫度)는 $65^{\circ}C$이었고, $37^{\circ}C$에서 생육(生育)하지 않는 절대(絶對) 고온균(高溫菌)이었으며 최적(最適) pH는 6.5내외(內外)이었다. 3. NaCl에 대(對)한 내성(耐性)은 NaCl 1% 이상(以上)에서 생육(生育)하지 못했다. 4. 공시균주(供試菌株)의 항생물질(抗生物質) 내성(耐性)은 Penicillin G는 $10{\mu}g/m{\ell}$, Chloramphenicol은 $0.5{\mu}g/m{\ell}$이었다. 5. Vitamin 요구성(要求性)은 Ca-pantothenate와 pyridoxine-HCl을 절대적(絶對的) 생육인자(生育因子)로 요구(要求)하였고 niacin을 자극적(刺戟的) 생육인자(生育因子)로 요구(要求)하였다. 6. 공시균주(供試菌株)는 최대(最大) 흡수파장(吸收波長)이 420nm 부근(附近)의 색소(色素)를 생성(生成)하였고 그의 생성능(生成能)은 약(弱)하였다. 7. 공시균주(供試菌株)의 균체 지방산(脂肪酸) 조성(組成)은 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.