库布齐沙地生物土壤结皮中解磷菌的分离鉴定及解磷能力

Identification and isolation of phosphorus-solubilizing bacteria of biological soil crusts in Kubqi sandland and their phosphorus-solubilizing capability

解磷菌对生物土壤结皮（Biological soil crusts，BSCs）中不同形态磷之间的转化起重要的生物驱动作用. 以无机磷和有机磷培养基分离筛选库布齐沙地BSCs中的解磷菌，基于16S rRNA基因进行分类鉴定；采用钼锑钪比色法测定菌株解无机磷能力；采用钒钼比色法测定其解植酸磷能力，以植酸酶活性表示. 结果共分离得到33株可在无机磷（磷酸钙）培养基上生长迅速的细菌，以Bacillus属和Sphingomonas属为主；其中18株菌可以使PVK培养基变色，解无机磷能力较强，达0.422-3.531 mg/mL；这18株菌中有15株可在植酸钙培养基上生长，其植酸酶活力为2.45-20.84 IU/mL，主要为Sphingomonas属.

Phosphate-solubilizing bacteria （PSB） play a fundamental biological role in the transformation of different phosphorus forms in biological soil crusts （BSCs）. To investigate the community composition of PSB in BSCs of Kubqi sandland and capability to dissolve phosphorus, inorganic and organic phosphorus medium was used to isolate phosphorus-solubilizing bacteria. A preliminary identification was based on the 16S rRNA gene; spectrophotometry of molybdate-antimony-scandium and vanadium-ammonium-molybdate were used to measure the inorganic and organic phosphorus-solubilizing capabilities, respectively; the organic phosphorus-solubilizing ability was indicated by phytase activity. The results showed that a total of 33 phosphorus bacteria were isolated from BSCs in Kubqi sandland, which grew rapidly on inorganic phosphorus medium, and were dominated by Bacillus and Sphingomonas; among them, 18 strains changed the color of PVK medium with inorganic phosphorus solubilizing capability of 0.422–3.531 mg/mL; 15 of the 18 strains grew on phytate-Ca medium with phytase activity of 2.45–20.84 IU/mL, and Sphingomonas was dominant. This study preliminarily revealed the composition and ability of PSB in BSCs of Kubqi sandland, which provides a basis for understanding and using desert PSB for other applications.