Algicidal activity of Achromobacter sp. (strain YZ) isolated from yellow sea: An assessment with bloom causing cyanobacterium Microcystis aeruginosa

Based on the bioassay-guided strategy, we isolated 6-six allelochemicals [cichoric acid (I), 1,3-dicaffeoylquinic acid (II), 4,5-dicaffeoylquinic acid (III), chlorogenic acid (IV), 1-hydroxy-2-phthoic acid (V), echinacoside (VI)] from the roots of Echinacea purpurea (L.) Moench. Their structures were identified by nuclear magnetic resonance (NMR) and electrospray ionization mass spectrometry (ESI-MS) spectroscopic data. The bioassays studies included allelopathic and algicidal activities to test the effects of extracts and isolated fractions against the test weeds (Amaranthus viridis L., Portulaca oleracea L. and Microcystis aeruginosa Kutzing). At 100 µg/mL, compound (II) inhibited the shoot length and germination of A. viridis and P. oleracea weeds with the germination RI of -0.95±0.04 and -0.95±0.02, respectively. Furthermore, compound (III) showed the strongest inhibition of root length of P. oleracea L. We also found that compounds I-VI have algicidal activity. The compound (I) at low inoculum (5.0×102 cells mL-1) and high inoculum (1.0×104 cells mL-1), showed the highest algicidal activity of 78 % and 87.67 % 6 h after the treatment at 5 µg mL-1 respectively.

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Isolation, identification, and algicidal activity of aerobic denitrifying bacterium R11 and its effect on Microcystis aeruginosa

Water Science & Technology ◽

10.2166/wst.2016.085 ◽

2016 ◽

Vol 73 (11) ◽

pp. 2600-2607 ◽

Cited By ~ 3

Author(s):

Jun-feng Su ◽

Si-cheng Shao ◽

Ting-lin Huang ◽

Fang Ma ◽

Kai Zhang ◽

...

Keyword(s):

Cell Density ◽

Microcystis Aeruginosa ◽

Bacterial Cell ◽

Algal Cell ◽

Algicidal Activity ◽

Algicidal Bacteria ◽

Rrna Gene ◽

Denitrifying Bacterium ◽

Cell Densities ◽

Water Blooms

Recently, algicidal bacteria have attracted attention as possible agents for the inhibition of algal water blooms. In this study, an aerobic denitrifying bacterium, R11, with high algicidal activity against the toxic Microcystis aeruginosa was isolated from lake sediments. Based on its physiological characteristics and 16S rRNA gene sequence, it was identified as Raoultella, indicating that the bacterium R11 has a good denitrifying ability at 30 °C and can reduce the concentration of nitrate-N completely within 36 h. Additionally, different algicidal characteristics against Microcystis aeruginosa were tested. The results showed that the initial bacterial cell density and algal cell densities strongly influence the removal rates of chlorophyll a. Algicidal activity increased with an increase in the bacterial cell density. With densities of bacterial culture at over 2.4 × 105 cell/mL, algicidal activity of up to 80% was obtained in 4 days. We have demonstrated that, with the low initial algal cell density (OD680 less than 0.220), the algicidal activity reached was higher than 90% after 6 days.

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