Petursdottir S K, Kristjansson J K
Department of Biotechnology, Technological Institute of Iceland, Reykjavík.
Extremophiles. 1997 May;1(2):94-9. doi: 10.1007/s007920050020.
Mesophilic, moderately halophilic bacteria were isolated from a silica-rich geothermal lake, the Blue Lagoon in Iceland. The isolates are strictly aerobic, but reduce nitrate to nitrite, and are oxidase- and catalase-positive. The nonsporeforming and nonmotile Gram negative rods are 0.6-0.8 microm in diameter and variable in length (9-18 microm), and contain gas vacuoles. The GC content in their DNA is 66.15%. The minimum, optimum, and maximum temperatures for growth are 22 degrees C, 45 degrees C, and 50 degrees C, respectively. The isolates do not grow without added salt in the medium and can grow at up to 7% NaCl (w/v). The optimal salinity for growth is 3.5%-4% NaCl. The pH range for growth is 6.5-8.5, with the optimal pH at 7.0. At optimal conditions the bacterium has a doubling time of 80 min. The main cytochrome is a membrane-bound cytochrome c with an alpha-peak at 549nm. Sequencing of 16S rRNA from the type strain ITI-1157 revealed it to be a proteobacterium of the alpha-subclass with the closest relatives being Roseobacter litoralis and Paracoccuss kocuri. The new isolates do not contain bacteriochlorophyll a and are considered to represent a new genus and a new species, Silicibacter lacuscaerulensis.
嗜温、中度嗜盐细菌是从冰岛富含二氧化硅的地热湖——蓝湖中分离出来的。分离出的细菌严格需氧，但能将硝酸盐还原为亚硝酸盐，氧化酶和过氧化氢酶呈阳性。这些不形成芽孢、无运动性的革兰氏阴性杆菌直径为0.6 - 0.8微米，长度可变（9 - 18微米），并含有气泡。其DNA中的GC含量为66.15%。生长的最低、最适和最高温度分别为22℃、45℃和50℃。分离出的细菌在培养基中不添加盐就无法生长，在高达7% NaCl（w/v）的条件下能够生长。生长的最适盐度为3.5% - 4% NaCl。生长的pH范围是6.5 - 8.5，最适pH为7.0。在最佳条件下，该细菌的倍增时间为80分钟。主要细胞色素是一种膜结合细胞色素c，其α峰在549nm处。对模式菌株ITI - 1157的16S rRNA进行测序表明，它是α亚类的变形杆菌，与滨海红杆菌和科氏副球菌亲缘关系最近。新分离出的细菌不含细菌叶绿素a，被认为代表一个新属和一个新物种，即蓝湖硅杆菌。
