侧孢短芽孢杆菌溶藻活性代谢产物部分特性的研究

Research on some characteristics of the extracellular algae-lysing components from Brevibacillus laterosporus

研究了不同因素对侧孢短芽孢杆菌（Brevibaci Uuslaterosporus）无菌滤液溶藻效果的影响，并对无菌滤液进行了紫外光谱扫描分析，探讨侧孢短芽孢杆菌溶藻活性代谢产物的物质特性、探究物质的组成成分．结果显示：无菌滤液分别经不同温度、pH值、蛋白酶和紫外照射时间处理后，均仍具有极为显著的溶藻能力（P〈0．01），溶藻实验7d后颤藻（Oscillatoria sp．）叶绿素a质量浓度的平均下降率分别为：58．65％、63．88％、61．50％和62．61％，藻体干重的平均下降率分别为：39．77％、39．30％、36．49％和37．02％，表明溶藻活性代谢物质具有耐酸、耐碱、耐高温、抗蛋白酶水解、抗紫外辐射的特性；同时，分别在4、28℃环境中贮存28d的无菌滤液，始终保持着极高的溶藻活性，溶藻实验7d后颤藻叶绿素a质量浓度的平均下降率分别为：50．84％和60．39％，藻体干重的平均下降率分别为：37．82％和37．54％，说明该物质的结构极其稳定，在环境中可长久存在；另外，加热与未加热处理的无菌滤液的紫外光谱最大吸收峰都在290～300nm之间．分析表明，溶藻活性代谢产物极大程度上属于具有极强稳定性的肽类物质．

In this study, the influences of different factors on algicidal effects of the sterile filtrate of Brevibacillus laterosporus were detected and the ultraviolet spectrum scanning analysis of the sterile filtrate were done to find the characteristics and compositions of the extracellular algae-lysing components of the bacterium. The results showed that algicidal abilities of the sterile filtrate of bacterial suspensions were all highly significant （p 〈 0.01 ） after the treatments by different temperatures, pH value, proteases and ultraviolet radiation exposure times. The average descent rates of the chlorophyll-a concentrations of Oscillatoria were 58.65%, 63.88%, 61.50% and 62.61%, and the average descent rates of the algal dry weights were 39.77 %, 39.30%, 36.49 % and 37.02%, respectively, in 7 days later. It indicated that the extracellular algae-lysing components from Brevibacillus laterosporus had the special characteristics of resistances to strong acid and alkali, high temperature, enzymolysis and ultraviolet radiation. Mean- while, the sterile filtrate of bacterial suspensions, stored at temperatures of 4℃ and 28℃ for 28 days separately, still maintained a high algae-lysing activities all the time. The average descent rates of the chlorophyll-a concentration of Oscillatoria were 60.84% and 60.39% ,and the average descent rates of the algal dry weights were 37.82% and 37.54% ,respectively, in 7 days later. These illustrated that the structure of the algae-lysing components from Brevibacillus laterosporus were extremely stable and the components could exist for a long time in the environment. In addition, the results of the maximum absorption peak of ultraviolet spectrum of the sterile filtrate of bacterial suspensions, treated by heating and without heating respectively, were all between 290 and 300nm. Therefore, it speculates that the algae-lysing components belonged to peptides which had strong stability.