中文摘要：

[目的]探明羊八井地热田放线菌的数量、种类组成、拮抗活性和酶活性。[方法]采用稀释平板法对羊八井地热田底泥和水样放线菌进行分离,通过形态特征、培养特征和16S rRNA基因系统发育分析的方法研究样品中度嗜热放线菌的多样性,并对分离到的放线菌进行抑菌、酶活性及温度耐受试验。[结果]从羊八井温泉底泥和水样中分离到21株中度嗜热放线菌,分布于放线菌门放线菌纲3个亚目3个科3个属,即链霉菌属（Streptomyces）、拟诺卡氏菌属（Nocardiopsis）和小单孢菌属（Micromonospora）。21株中度嗜热放线菌中,14.2%的菌株具有纤维素酶活性,52.3%的菌株具有过氧化氢酶活性,28.6%的菌株具有硝酸盐还原活性,33.3%的菌株可产生硫化氢,只有1株菌对大肠杆菌（E.coil）有抑菌活性,21株中度嗜热放线菌最适生长温度为45~55℃,超过65℃都不能生长。[结论]羊八井地热田放线菌多样性较丰富,产酶特性良好,为开发利用地热环境放线菌资源奠定了基础。

英文摘要：

[Objective]The aim was to explore the quantity,composition,antagonistic activity and enzyme activity of actinomyccetes from geothermal field in Yangbajing.[Method]Thermophilic actinomycetes were isolated via plate dilution from the sediment and water of Yangbajing geothermal field in Tibet Province.Based on the morphology,cultural characteristics and 16 S rRNA sequence,diversity of thermophilic actinomycetes were studied,antibacterial activity,enzyme activity and temperature tolerance tests were conducted on isolates.[Result] The results showed that 21 isolates were identified and found to distribute into 3 genus：Streptomyce,Micromonospora and Nocardiopsis.Among those,14.2% produced cellulase,52.3% produced catalase,33.3% produced H2 S and 28.6% could reduce nitrate,and 1 strain had antibacterial activity against Escherichia coil.The optimal growth temperature range for strains was 45-55 ℃ and temperature over 65 ℃ totally blocked the growth.[Conclusion] The discovery of diverse thermophilic actinobacteria from Yangbajing geothermal field indicates a potential source for enzymes.This study lays a foundation for the exploration and utilization of thermophilic actinobacteria resource.