一株具有溶藻特征的假单胞菌分离鉴定及其溶藻动力学研究

Isolation,Identification and Algae-lysing Kinetics of an Algicidal Bacteria Pseudomonas sp.

从田螺内脏中分离获得一株溶藻菌株(命名为W10),利用16S rDNA序列分析及生理生化特征对该菌株进行了鉴定,探究了其对铜绿微囊藻的作用方式、菌液及其无菌上清液在不同条件下的溶藻特性,并构建了溶藻动力学模型。结果表明:菌株W10归属于假单胞菌属(Pseudomonas sp.,GenBank ID为MN688696);W10溶藻式是通过分泌某些热稳定性差的溶藻物质间接作用于铜绿微囊藻,使其裂解、溶解;NA和淀粉培养基对W10菌株的培养效果无显著差异(P>0.05),二者显著优于改良基础培养基(P<0.05),但因NA培养基成分复杂,故确认淀粉培养基适宜于菌株W10培养;同一生长时期的菌液及其无菌上清液溶藻效果无显著差异(P>0.05),二者均表现为稳定期与衰亡期最高,二者无显著差异(P>0.05),然后依次是对数期和延滞期;当菌液与藻液体积比为1∶10时,W10菌液溶藻率最高为80.05%,而无菌上清液的溶藻效果与投加量呈正相关,在1∶2处理溶藻率最高为92.15%;当菌藻比1∶10以铜绿微囊藻为降解底物时,菌株W10的溶解作用遵循一级反应动力学。

An algicidal bacteria strain W10 was isolated from a snail's viscera and identified based on 16S rDNA gens and biochemical and morphological characteristics.The algae-lysing way of W10 and the effects of different conditions on the algae-lysing action were investigated to analyze the algicidal characteristics of strain W10 and its filtrate,and then built the algae-lysing kinetic model of W10.The results showed that strain W10 was identified as Pseudomonas sp.(Accession No.MN688696).And W10 indirectly attacked Microcystis aeruginosa by secreting algicidal substances with poor thermal stability.There was no significant difference of algicidal ratio(P>0.05)between NA and starch medium,both of which were significantly better than the modified basic medium(P<0.05).However,due to the complex composition of the NA medium,it was confirmed that the starch medium was suitable for cultivating W10.There was no significant difference of algicidal ratio(P>0.05)between W10 and its filtrate at the same growth phase.The algae lysing of W10 and its filtrate were highest in the stable growth phase and the decay growth phase.There was no significant difference of algicidal ratio(P>0.05)between the stable growth phase and the decay growth phase,followed by the logarithmic growth phase and the delay growth phase.Furthermore,when the volume ratio of W10 to Microcystis aeruginosa was 1∶10,the highest removal rate of W10 was 80.05%.But the algicidal effect of W10's filtrate was positively correlated with the dosage;the highest removal rate of W10's filtrate was 92.15%in the 1∶2 treatment.When the bacteria-algae ratio of 1∶10 and Microcystis aeruginosa was used as degradation substrates,the dissolution of Microcystis aeruginosa by W10 followed first-level kinetics.