This study reports for the first time the isolation, identification and characterization of lipase-producing thermophilic strain from the geothermal water of the El Chichon volcano crater lake. Two strains were identified by 16S rRNA sequencing as Geobacillus jurassicus CHI2 and Geobacillus stearothermophilus CHI1. Results showed that G. jurassicus CHI2 is Gram-positive, able to ferment maltose, fructose and sucrose and to hydrolyze starch and casein; while G. stearothermophilus CHI1 showed to be Gram-variable, able to ferment maltose and fructose and to hydrolyze starch. Colonies of both strains presented irregular shape, umbilicated elevation of gummy texture and cells presented flagellar movement to survive in fluids with high temperature and mass gradients due to complex phenomena of heat and mass transfer present in the geothermal fluids. Lipase production for G. stearothermophilus CHI1 was also evaluated. It was found that this strain possesses a growth associated with extracellular lipase production with a high activity of 143 U/mL at 8.3 h of incubation time, superior to the activities reported for other microorganisms of genus Geobacillus; for this reason, it can be said that the thermal flow of the El Chichon volcano crater lake can be a useful source of lipase-producing thermophilic bacteria.

中文翻译：

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El Chichón 火山口湖地热水流中嗜热微生物的特征

本研究首次报道了从 El Chichon 火山口湖地热水中分离、鉴定和表征产脂肪酶的嗜热菌株。通过16S rRNA测序鉴定出两种菌株为侏罗地芽孢杆菌CHI2和嗜热脂肪地芽孢杆菌CHI1。结果表明，G. jurassicus CHI2 为革兰氏阳性菌，能够发酵麦芽糖、果糖和蔗糖，水解淀粉和酪蛋白；而 G. stearothermophilus CHI1 显示为革兰氏变异，能够发酵麦芽糖和果糖并水解淀粉。由于地热流体中存在复杂的传热和传质现象，两种菌株的菌落都呈现出不规则的形状，脐状隆起的胶状纹理和细胞呈现出鞭毛运动以在具有高温和质量梯度的流体中存活。还评估了 G. stearothermophilus CHI1 的脂肪酶生产。发现该菌株具有与胞外脂肪酶产生相关的生长，在 8.3 小时的孵育时间具有 143 U/mL 的高活性，优于报道的其他土芽孢杆菌属微生物的活性；因此，可以说 El Chichon 火山口湖的热流可以成为产生脂肪酶的嗜热细菌的有用来源。