Characterization of Thermophilic Microorganisms in the Geothermal Water Flow of El Chichon Volcano Crater Lake

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 asGeobacillus jurassicusCHI(2)andGeobacillus stearothermophilusCHI(1). Results showed thatG. jurassicusCHI(2)is Gram-positive, able to ferment maltose, fructose and sucrose and to hydrolyze starch and casein; whileG. stearothermophilusCHI(1)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 forG. stearothermophilusCHI(1)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 genusGeobacillus; 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.