Diversity Of Cultured Thermophilic Anaerobes In Hot Springs Of Yunnan Province

Thermophilic anaerobes are Archaea and Bacteria that grow optimally at temperatures of 50℃or higher and do not require the use of O2 as a terminal electron acceptor for growth. Study on the thermophilic anaerobes will help to understand how life can thrive under extreme conditions.Meanwhile thermophilic anaerobes are important resources for the potential application and development of thermophilic enzyme.The diversity of cultured thermophilic anaerobes from hot springs (pH6.5-7.5; 70-94℃) in Rehai of Tengchong, Balazhang of Longlin, Eryuan of Dali,Yunnan, China was studied in this thesis.50 strains were obtained from the hot springs mentioned above using Hungate anaerobic technique. Based on their special characterization,30 strains were selected for analysis of their 16S rDNA sequences. Phylogenetic analysis showed that 28 strains belonged to the members of five genera:Caldanaerobacter, Calaramator, Thermoanaerobacter, Dictyoglomus and Fervidobacterium, which formed five branches on the phylogenetic tree. Members of Caldanaerobacter were found widely distributed in hot springs. Besides,2 strains of methanogenic archaea were obtained. The majority of the isolates were the known species that have been published previously. However,7 strains of them were possibly to determine as the novel species for their lower 16S rDNA sequence similarites with the other described anaerobes (less than 97%), and their morphology, physiological and biochemical characteristics, G+C mol% and phylogeny were further studied.In summary, this was the first time that the diversity of cultured thermophilic anaerobes from hot springs in Yunnan was systemically studied. The strains isolated in this work could enrich the resource of thermophilic anaerobes, and would be beneficial to further study of their diversity, distribution among different regions and the potential application of thermophilic enzyme.