拉恩氏菌W25对缓冲容量的响应及其产酸特性

【目的】进一步了解拉恩氏菌W25的溶磷机理和对土壤缓冲容量的响应。【方法】在液体摇瓶培养过程中，采用调节培养液pH的方法研究模拟土壤的缓冲容量对拉恩氏菌W25溶磷量的影响；通过单因子试验和HPLC相结合的方法，研究不同碳源、磷源条件下W25的溶磷能力及产酸特性。【结果】拉恩氏菌W25在磷酸三钙培养液中培养120 h后有效磷含量达到最大值，培养液有效磷含量与培养液pH变化之间呈极显著负相关性(P<0.01)；W25在培养第48?96 h具有较强的缓冲能力，培养液有效磷含量加碱处理与未加碱处理差异不显著(P<0.05)，从第120 h开始，缓冲能力开始减弱，在168 h后基本丧失了缓冲能力；W25在不同碳源条件下溶磷能力差异显著(P<0.05)，依次为葡萄糖>乳糖>蔗糖>甘露醇>淀粉，不同磷源中培养液有效磷含量差异极显著(P<0.01)，依次为磷酸三钙>磷酸铁>磷酸铝>磷矿粉；不同碳源、磷源条件下W25培养液中有机酸的种类和浓度差异较大，W25溶磷能力的大小不仅与产酸的种类有关，而且也与产酸的浓度有关。【结论】研究结果为更深入研究拉恩氏菌溶磷机理提供条件，为拉恩氏菌的应用提供理论基础。

Solubilization ability of Rahnella sp. W25 under buffering condition and its acetic-producing characteristics

[Objective] Objectives of this study were to further understand the mechanism on phosphate solubilization of Rahnella sp. W25 and its solubilization ability under buffering condition. [Methods] Regulating pH of nutrient solution was conducted in the process of liquid shake flask culture to research the influence of buffer capacity on the phosphate solubilizing ability of Rahnella sp. W25 under simulation soil condition. Research the solubilizing ability and acetic-producing characteristics under different carbon and phosphorus sources condition though single factor text and HPLC. [Results] The result showed that the available phosphorus content reached up to its maximum after cultivated 120 h in the solution of tricalcium phosphate. The change of available phosphorus content and pH in solution showed significant negative correlation (P<0.01). At cultivated 48?96 h, strain W25 had stronger buffering capacity and the difference of available phosphorus content between regulating pH using and without using NaOH was not significant (P<0.05). Strain W25 weaken after cultivated 120 h and basically lost buffering capacity after cultivated 168 h. The solubilizing ability showed significant different under different carbon sources (P<0.05). The order of solubilization ability as follows: glucose>lactose>sucrose>mannitol>starch. It also showed extremely significant different under different phosphorus sources (P<0.01). The order was tricalcium phosphate>iron phosphate>aluminum phosphate>ground phosphate rock. The type and concentration of organic acids were dissimilar under different carbon and phosphorus sources conditions. The solubilization ability of strain W25 was both related to the type and concentration of organic acids. [Conclusion] Results of this study could provide the condition of deeply researching mechanism on phosphate solubilization and the theoretical basis of application of Rahnella sp..