Research On Typical Odorous Compounds From Algae Metabolites And The Variation Rule

At present,eutrophication of lakes is becoming more and more serious.Blooming aglae consume dissolved oxygen in water,release some metabolites smelling disgusting.Off-flavor problems caused by algae-producing odorous compounds have been of the focuses in drinking water industry and aquaculture.Therefore,research on the relevance between off-flavor problems and the metabolites from algae has great significance.Water and algae samples were determined using solid-phase microextraction coupled with gas chromatography-mass spectrometry technology(SPME-GC/MS).In this study,the screened metabolites wereβ-Cyclocitral,β-Ionone,Indole and these compounds in samples were quantitative analysed.Relevances between algae andβ-Cyclocitral,β-Ionone,Indole were studied according to polder experiment and algae decomposition experiment.In the algae decomposition experiment,the contents ofβ-Cyclocitral,β-Ionone were decreasing with the time.At the high culture temperature,the decomposition rates ofβ-Cyclocitral,β-Ionone are higher than that at the low culture temperature:the decomposition rates ofβ-Cyclocitral were 98.6%,99.93%,99.96%at the temperature of 15℃,25℃,35℃, and the decomposition rates ofβ-Ionone were 87.6%,89.6%,94.2%respectively.The decomposition velocities of these two compounds in algae samples were faster than that in mud and algae mixed samples,the residual contents after decomposing in algae samples were also lower than that in mud and algae mixed samples because of the role of micro-organisms in mud and algae mixed samples.Decomposition of algae produced a lot of Indole in algae sample,the higher the culture temperature,the greater the content of Indole.25℃and 35℃were the best conditions for the degradation of Indole in mud and algae mixed samples.From the polder experiment,the contents ofβ-Cyclocitral,β-Ionone in water were incresing with the increasing of algae content.The contents of the two odorous metabolites were decreasing with the gradual death of algae.The degradation rate ofβ-Cyclocitral in water samples from four groups of polder experiment could reach 99%;the degradation rate ofβ-Ionone was the lowest:83.5%in the group which algae content was the lowest,and the three other groups could reach 94.8%～96.9%.Analysis results of water samples from Tai Lake indicated that the contents ofβ-Cyclocitral,β-Ionone were the largest in August when the algae breed.On Meiliang Bay and intake of Nanquan Water Plant,the contents ofβ-Cyclocitral were 1.4μg/L,4.2βg/L,andβ-Ionone contents were 0.24μg/L,1.5μg/L. Analysis results of water samples before filtration and after filtration from Tai Lake and polder indicated that:the existence form ofβ-Cyclocitral andβ-Ionone were particulate form mainly,the contents ofβ-Cyclocitral andβ-Ionone dissolved in water were extremely low.