Characterizations and Phylogeny of Thermostable Cellulolytic Bacterial Isolates
Fifty two cellulolytic thermophilic microorganisms were analyzed for their physiological characterization and phylogenetic systematics. Based on 16S rDNA sequence analysis, 3 strains from DCB and 4 novel isolates from southern Taiwan are close related to the genera of Bacillus and Geobacillus respectively. Among 4 new Geobacillus strains, strain T4, a Gram negative, motile, aerobically growing sporulating rod, can secrete thermostable endoglucanase. When strain T4 was grown in CMC medium, the cellulolytic enzyme activity in culture supernatants was stable up to 70¢XC. Based on 16S rDNA sequence analysis, DNA G+C content, phenotypic and physiological characteristics, as well as DNA-DNA hybridization, strain T4 was classified as Geobacillus thermoleovorans T4 (DSM 14791 = CCRC 17200). Furthermore, a phylogenetic tree of 20 related microorganisms was also constructed based on their thermostable cellulase amino acid sequences. Our sequence analysis shows that cellulases belonging to the large family of glycoside hydrolases (GHs) can be divided into four subfamilies: TC-1 (GH family 12 group), TC-2 (bacterial group £L in which fungal species Thermoascus aurantiacus fits), TC-3 (bacterial group £L£L), and TC-4 (GH family 1 group). Together with the 16S rDNA sequence analysis of strain T4 and 10 related microorganisms, strain T4 has a close phylogenetic relationship with subfamily TC-4 but far from subfamily TC-1.
Advisor:Chi-Hsin Hsu; Chan-Shing Lin; Jong-Kang Liu; Hsiu-Ping Pearl Lin; Hui-Liang Wang
School:National Sun Yat-Sen University
School Location:China - Taiwan
Source Type:Master's Thesis
Keywords:geobacillus thermoleovorans 16s rdna
Date of Publication:08/24/2004