三株溶藻细菌溶藻活性代谢产物的初步研究

Preliminary study on algae-lysing active metabolites of three algae-lysing bacteria

已知3株溶藻细菌L7、L8和L18的活性代谢产物具有明显的溶藻效果。为获得较高活性和浓度的目标产物,研究了培养基、碳源、氮源对溶藻效果的影响;为考察溶藻活性代谢产物保存和应用的环境条件,研究了其热、酸稳定性。在牛肉膏蛋白胨、淀粉、查氏和高氏1号4种培养基里,淀粉培养基最适宜用于获得溶藻活性代谢产物。以淀粉培养基为基础,碳、氮源组合依次为淀粉+(NH4)2SO4、淀粉+(NH4)2SO4,葡萄糖+KNO3时,3株溶藻细菌的溶藻活性代谢产物溶藻活性最高。这一结果为目标产物的分离奠定了物质背景。3株溶藻细菌溶藻活性代谢产物均具有良好的热稳定性,经热处理后,对叶绿素a的去除率仍高于73%。L7的无菌滤液调至pH值4.0或2.5,2h后丧失溶藻活性;L8和L18的无菌滤液调至pH值4.0,2h后未丧失溶藻活性,调至pH值2.5,2h后丧失溶藻活性。上述结果为溶藻活性代谢产物的分离奠定了基础。

It＇s known that the active metabolites of three algae-lysing bacteria L7, L8 and LI 8 have great lytic effect on Anabaena flos-aquae. For getting target products with higher activity and concentration, the effects of culture media, carbon sources and nitrogen sources on algae-lysing were studied. And to find out the condition of conservation and application of the algae-lysing active metabolites, their thermal and acid stability were studied. Among the culture medium, which were Beef Extract Peptone, Starch（starch soluble 10 g, K2HPO4 1 g, NaCI I g, MgSO4·7H20 1 g, （NH4）2SO42 g, pure water 1 L, pH 7.0-7.2 ）, Czapek and Gause＇s NO. 1 medium, the second one was the most suitable. Base on Starch medium, if the carbon and nitrogen source were starch ＋ （NH4）2SO4 for L7 and L8, and glucose＋ KNO3 for L18, the metabolites have the highest algae-lysing activity. The active metabolites of three algae-lysing bacteria have well heat stability. After heat treatment, which was in water bath of 50 ℃, 70 ℃, 90 ℃, or in autoclave of 121 ℃, I. I kg·cm^-3＇s pressure respectively for 20 min, the removal rate of Chla still exceeded 73%. Adjusting asepsis filtrate of L7 to pH4.0 or 2.5, it lost its algae-lysing activity in 2 hours. To L8 and L18, they kept their algae-lysing activity after adjusted to pH 4.0 2 hours, but lost them after adjusted to pH 4.0 2 hours. The results all above lay the foundation for the separation of algae- lysing active metabolites.