磷细菌A_9最佳生长条件研究

Study on Optimal Fermentation Conditions of A_9 Phosphobacteria

磷细菌广泛分布在土壤、根际等生态环境中,研究解磷细菌最佳生长条件,对于开发利用磷细菌,提高磷素利用效率具有重要作用。从陕西杨凌葡萄根际土壤分离筛选获得一株无机磷菌A9,对A9采用摇瓶发酵培养、平板计数法,分别对碳源、氮源、装液量、培养时间4个单因素进行初步研究。结果表明,氮碳源是磷细菌生长不可缺的主要因素之一,麸皮为最佳碳源,蚕蛹粉为最佳氮源。氧是磷细菌生长不可缺少的因素之一,装液量不同反映对菌株供氧能力不同,确定A9最佳装液量为每250 mL三角瓶中装入75 mL。培养时间的长短决定磷细菌利用营养的多少,确定A9最佳培养时间为42 h。

Phosphobacteria are widely distributed in soil,rhizosphere and other ecological environment.Understanding the fermentation conditions of the bacteria in decomposing phosphates is helpful to apply them in improving P use efficiency.Phosphobacteria A9 was separated form the rhizospheric soil of grapes in Yangling,Shaanxi,and shake-flask cultured.Single-factor approaches were conducted to investigate fermentation effect of four factors included nitrogen source,carbon source,cultivated liquid capacity and cultivated time with the indicator of bacteria number.The results were as follows：（1） Carbon and nitrogen sources are the main factors for phosphobacteria growth.The optimal fermentation conditions of Phosphobacteria A9 are carbon source 2 g·mL^-1 bran,nitrogen source 4 g·mL^-1 powder of silkworm.（2） Oxygen is one of the main factors for phosphobacteria growth.The different cultivated liquid volume can reflect the oxygen capacities for bacteria.The optimal volume culture condition was 75 mL Phosphobacteria A9 in 250 mL flask.（3）The cultivated times are decided for nutrients utilizing of phosphobacteria.The optimal cultivated time of Phosphobacteria A9 is 42 h.