山口红树林根际土壤可培养细菌多样性及其活性筛选

为探讨广西山口红树林土壤可培养细菌的多样性，采用纯培养分离技术对采集的25个红树林样品进行可培养细菌多样性分析，挑选117株菌株进行16S rRNA基因测序并构建系统发育树分析。结果表明117株菌株分别属于9个纲20个目27个科35个属，9个纲包括α-变形菌纲（21.37%）、β-变形菌纲（1.71%）、γ-变形菌纲（12.82%）、δ-变形菌纲（0.85%）、噬纤维菌纲（0.85%）、鞘脂杆菌纲（0.85%）、黄杆菌纲（2.56%）、放线菌纲（27.35%）、芽孢杆菌纲（31.62%）。优势属为芽孢杆菌属，占所有菌株的28.20%，此外α-变形菌纲、γ-变形菌纲、黄杆菌纲和放线菌纲中发现了7株潜在的新物种。分离菌株的产酶活性检测表明，山口红树林根际土壤蕴含丰富的产淀粉酶、蛋白酶、葡聚糖、纤维素酶和几丁质酶等生物活性酶的菌株，其中芽孢杆菌纲的产酶菌株数最为丰富。初步研究结果表明广西山口红树林土壤可培养细菌资源丰富，新物种资源多样，是农业微生物开发应用的重要资源库。

Screening the diversity and activity of culturable bacteria isolated from mangrove rhizosphere soil at Shankou

Distribution of culturable bacteria in the Guangxi Shankou mangrove rhizosphere sediments was investigated in this study. 25 sediment samples collected from Guangxi mangrove rhizosphere sediments were used for bacterial diversity research by using the culture dependent method. 117 isolates were selected for further study. Phylogenetic analysis based on the partial 16S rRNA sequences clustered the 117 isolates into 9 classes, 20 orders, 27 families and 35 genera. 9 classes include Alphaproteobacteria(21.37%), Betaproteobacteria(1.71%), Gammaproteobacteria(12.82%), Deltabacteria(0.85%), Cytophagia(0.85%), Sphingobacteria (0.85%), Flavobacteria(2.56%), Actinobacteria(27.35%) and Bacilli(31.62%). The dominant genus was Bacillus, in which takes a great proportion of 28.20%. Additionally, 7 potential novel species from Alphaproteobacteria, Gammaproteobacteria, Flavobacteria and Actinobacteria were obtained. The results showed that bacteria producing amylase, protease, glucanase, cellulase and chitinase were abundant in the rhizosphere sediments of Shankou mangrove. Bacilli produced the most multiple enzymes. The preliminary study indicates that population diversity of culturable bacteria was abundant in the Guangxi Shankou mangrove rhizosphere sediments, and this worth further studies.