Algicidal activity of an actinomycete strain, Streptomyces rameus, against Microcystis aeruginosa.
An actinomycete strain (KKU-A3) with algicidal activity against Microcystis aeruginosa was isolated from soil in Khon Kaen Province, Thailand. Based on its phenotypic characteristics and 16S rDNA sequence, strain KKU-A3 was identified as Streptomyces rameus. Strain KKU-A3 also exhibited algicidal activity against the cyanobacteria Synechococcus elongatus, Cylindrospermum sp. and Oscillatoria sp. A mathematical and statistical technique was used to optimize the culture conditions and maximize its anti-Microcystis activity. The single factor experiments indicated that glucose and casein were the most effective carbon and nitrogen sources, respectively, and produced the highest anti-Microcystis activity. Response surface methodology indicated that the optimum culture conditions were 19.81 g/L glucose and 2.0 g/L casein at an initial pH of 7.8 and an incubation temperature of 30 °C. The anti-Microcystis activity increased from 82% to 95% under optimum conditions. In an internal airlift loop bioreactor, the removal of M. aeruginosa KKU-13 by the bacterium was investigated in batch and continuous flow experiments. In the batch experiment, KKU-A3 displayed maximum anti-Microcystis activity of 95% at day 7, whereas in the continuous flow experiment, KKU-A3 displayed maximum anti-Microcystis activity of 95% at day 10.
Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand E-mail: thesom@kku.ac.th.
Kanchariya
K
Phankhajon
Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand E-mail: thesom@kku.ac.th.
Anchana
A
Somdee
Department of Microbiology, Faculty of Science, Khon Kaen University, Khon Kaen, Thailand E-mail: thesom@kku.ac.th.
Theerasak
T
Somdee
D061046:Biological Control Agents; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal; D046931:Microcystis / Q000502:physiology*; D013302:Streptomyces / Q000235:genetics / Q000502:physiology*; D013785:Thailand; D014871:Water Microbiology
D061046:Biological Control Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal