Preliminary Research on the Isolation of Algicidal Bacteria and Enhanced Biofilm Reactor to Algae Control

摘要

Entrophication occurs worldwide frequently and causes seriously impact on environment and damage to human health.It has become one of the most urgent aquatic environmental problem,and several techniques have been applied to algae control.Because its advantages of economics,convenience and safety,biological methods has been attracting more and more attentions.Recently,we focused on the study of algae-lysis bacteria as well as enhanced-biofilm reactor,which will provide theorical bases for algae control in the lakes and reservoirs.We took the A.flos-aquae as a host and established the method to isolate the alage-lysing bacteria from algae blooms of Dianchi Lake.A 3-step process was carried out,including plaque-forming,pure cultivation on the SM medium and the test of algae-lysis effect.As a result,10 bacterial strains were isolated.On the basis of isolation experiment,we conducted an indoor experiment to investigate the inhibitory effect of biofilm reactors to two typical bloom-forming algae in China-A.flos-aquae and M.aeruginosa.We made three different kinds of biofilm reactor with sponge as the biological packing,including Biofilm reactor (BR),Rice straw enhanced-biofilm reactor (RSBR) and Alage-lysing bacteria enhanced-biofilm reactor (ABBR).All of the three reactors were of great use for lysing A.flos-aquae and M.aeruginosa,the inhibition ratio of which were all above 93％ after 5 days' treatment.The result indicated that the inhibitory effect of RSBR was better than that of BR.After 3 days' treatment with the flow rate of 20 mL/min,the inhibition ratios of them were,respectively 68.0％ and 75.8％ to A.flosaquae,and 56.0％,80.4％ to M.aeruginosa.Furthermore,the alage-lysing bacteria did enhance the ABBR to behave the best capability.Under the same condition,the inhibition ratios of the RSBR and ABBR were respectively 68.5％,81.3％ and 24.3％,61.4％.These reactors were more effective to A.flos-aquae than to M.aeruginosa.This investigation shows that the abilities of alage-lysing bacteria and enhanced-biofilm reactor are significant to the algae-inhibition.The use of alage-lysing bacteria and enhanced-biofilm reactor will be a good trial,and provide a new method to control the algae blooms water environment in our country,especially for Dianchi Lake.