Isolation Of Thermophiles And Screening Of Thermozymes From The Hotsprings Of Mid-West-China And Purification Of A Thermostable Cellulase

Thermophiles and the enzymes from them, which are known as thermozymes, have recently attracted much attention because of their potential in industrial application and their general value in scientific research. The ecological distribution of thermophiles, the industrial application of thermozymes, the structure and molecular diversity of cellulase, as well as the activity assays are reviewed here. Our research foused on the isolation of thermophiles and the screening of thermozymes, from the hotsprings of Mid-West-China, the purification of a thermostable cellulase was also proceeded.A total of 47 culturable thermophilic strains, which have been mainly divided into two genus Anoxybacillus and Geobacillus according to the phylogenetic analysis of the 16S rDNA sequences, have been isolated from the hotsprings. Only one which secretes red pigment is classed into Meiothermus. These results suggest that thermophilic bacilli are predominant in the environment with moderate high temperature. 85% of the 158 thermophiles appear to be able to synthese thermozymes and most of them produce multienzyme system which has great potential in industrial application. Moreover, the enzyme production is distinct both intraspecifically and interspecifically. Three thermophiles showed positive in the plate screening of cellulase. According to the comparative results of the stability of enzyme production and the characteristics of the crude cellulase, one of them named XJT16 have been chosen for the further research. XJT16 is identified as one strain of the species Geobacillus stearothermophilus, which is supported by its partial physiological charateristics and 16S rDNA sequence analysis. The research on the partial purified cellulase from XJT16 indicates that it may be an endoglucanase. Further studies are still needed according to the results of SDS-PAGE which showed multiple protein bands.