Streptomyces alboflavus RPS and Its Novel and High Algicidal Activity against Harmful Algal Bloom Species Phaeocystis globosa

Abstract

Phaeocystis globosa blooms have frequently occurred along coastal waters and exerted serious impacts on ecological environments by releasing toxic hemolytic substances, forming nuisance foam, and causing oxygen depletion. An actinomycete strain RPS with high algicidal activity against P. globosa was isolated and identified as Streptomyces alboflavus, based on morphology, physiological and biochemical characteristics, and 16S rDNA sequence analysis. RPS lysed 95% of P. globosa within 48 h by releasing an extracellular active substance into the growth medium. The activity of RPS supernatant was sensitive to temperature at and above 50°C and insensitive to pH from 3 to 11. The molecular weight of the active substance was between 100 Da and 1000 Da, and approximately 90% of it was extracted by ethyl acetate. It was presumed that the active component efficiently inhibited the movement of P. globosa, caused the flagella to fall off the algae, and finally lysed the algal cells. RPS showed a wide target range against harmful algae. S. alboflavus RPS with high algicidal activity and such novel features of temperature and pH sensitivity, low molecular weight, algicidal process, and target range possesses great potential in the biological control of P. globosa blooms.

Characterization and effects of two algicidal isolates on antioxidase activities of Chlorella pyrenoidosa

“…Strain AM11 was isolated on PDA medium and cultured in Czapek' solution . Streptococcus enrichment (SE) medium was used to culture host algae (i.e., C. pyrenoidosa ) under white fluorescent light (50 μmol photons m −2 s −1 ) using a light period of 12 hours at 25°C .…”

“…All types of algicidal bacteria may generate various algicide and algicidal mechanisms . Many researchers support the hypothesis that indirectly algicidal bacteria could lyse or kill algae cell mainly through inhibition of the respiratory chain to inhibit synthesis of algae cell wall or spore formation .…”

The first evidence of deinoxanthin from Deinococcus sp. Y35 with strong algicidal effect on the toxic dinoflagellate Alexandrium tamarense

“…To test for algicidal activity, A. tamarense was inoculated into a 24-well cell plate, and the fluorescence intensity (RFU) of algae in each well was measured at an excitation wavelength of 440 nm and emission wavelength of 680 nm (Spectra max M2, Molecular Devices Corporation) and the result treated as algal biomass [34]. One red colored strain was isolated, which showed high algicidal activity, and this strain was designated Y35.…”

Algicidal Activity of Novel Marine Bacterium Paracoccus sp. Strain Y42 against a Harmful Algal-Bloom-Causing Dinoflagellate, Prorocentrum donghaiense

“…Considerable efforts have been devoted to the investigation of environmental conditions that regulate the occurrence and maintenance of P. donghaiense blooms and the cellular responses of this dinoflagellate to different conditions, such as N/P repletion, N/P depletion, different N/P substrates, acidification, and eutrophication (25)(26)(27)(28)(29). Although many algicidal bacteria have been identified and exploited in the control of Microcystis aeruginosa (5,7,14,17,30), Alexandrium tamarense (9,12,18,19), Phaeocystis globosa (8,11,16,(31)(32)(33), and Skeletonema costatum (34)(35)(36)(37), few studies have reported bacteria with algicidal effects against P. donghaiense. Therefore, an effective biocontrol method for the prevention and dissolution of P. donghaiense algal blooms must be developed.…”