溶藻菌R1的分离鉴定以及对栅藻共处代谢的影响

Identification of algicidal bacterium R1 and its influence on the metabolism of scenedesmus in a co-culture

摘要:

【目的】分离并鉴定溶藻菌和栅藻，并对溶藻菌抑制栅藻的机理进行分析。【方法】溶藻菌分离采用高氏一号培养基，经多次划线纯化而得；溶藻菌鉴定采用生理生化性质判定；栅藻分离和鉴定主要采用镜检和《中国常见淡水浮游藻类图谱》完成；溶藻菌对栅藻的影响分析测定包括：测定栅藻叶绿素a变化、水体中溶解氧变化、藻细胞数目变化、藻蛋白表达变化、抑藻特殊物质测定等。【结果】共分离出4株溶藻菌(R1?R4)，通过对其理化性质测定初步判定均属于芽孢杆菌属(Bacillus sp.)，其中溶藻菌R1对栅藻生长的影响最明显，其对栅藻叶绿素a的抑制率为65%、溶解氧最低达6.5 mg/L，远低于栅藻单独培养下的10.4 mg/L；栅藻单独培养条件下的蛋白质表达为0.845 7 mg/L，与溶藻菌R1共培养时栅藻蛋白表达仅有0.192 6 mg/L；傅里叶红外光谱(FTIR)测定表明溶藻菌对栅藻细胞结构产生影响；相差显微镜对溶藻菌R1-栅藻共培养动态观察图可以看出，溶藻菌R1对栅藻的生长具有明显的抑制作用。【结论】从影响栅藻细胞结构、栅藻蛋白表达、栅藻光合作用等方面进行了分析，为揭示溶藻菌对栅藻抑制的机理提供了一定的理论基础。

Abstract:

[Objective] objectives of this study were to isolate and identify algicidal bacteria and scenedesmus, then analyze the inhibition mechanism on scenedesmus by algicidal bacteria. [Methods] Streak culture and physio-chemical properties were used to purify and identify algicidal bacteria respectively. The methods in “Microscopy and Chinese common freshwater planktonic algae” were used to isolate and characterize scenedesmus. The items including chlorophyll a, DO, scenedesmus cells, alga protein expression, special matter of algal inhibition were analyzed to clarify the influences of algicidal bacteria on scenedesmus. [Results] Four algicidal bacteria (R1?R4) were isolated and identified their genus of Bacillus sp. based on their physi-chemical properties. Algicidal bacteria R1 was proved for its most inhibition effects on scenedesmus. The inhibition of chlorophyll a was 65%; DO was 6.5 mg/L, far below to 10.4 mg/L obtained by the sole-culture of scenedesmus; The alga protein was only 0.192 6 mg/L and also far below to 0.845 7 mg/L of the normal alga protein expression without the inhibition of algicidal bacteria R1. FTIR results showed algicidal bacteria R1 could influence scenedesmus cell structure. The obvious inhibition of algicidal bacteria R1 on scenedesmus was also proved through phase contrast microscope during their co-culture process. [Conclusion] The inhibition mechanism of algicidal bacteria on scenedesmus including scenedesmus cell structure changes, scenedesmus protein and scenedesmus photosynthesis so on have been analyzed.