Application of biosurfactant from Bacillus subtilis C9 for controlling cladoceran grazers in algal cultivation systems

Abstract

Open algal cultivation platforms often suffer crop losses to herbivorous grazers that have potential to devastate biomass production within a few days. While a number of studies suggest synthetic chemicals as control agents for voracious algal grazers, environmental and safety concerns associated with the use of these chemicals encourage the exploration of alternative biological control agents. We hereby propose the application of a biosurfactant produced by Bacillus subtilis C9 (referred to as C9-biosurfactant) for controlling cladoceran grazers commonly found in algal cultivation systems. The results indicated that C9-biosurfactant completely eradicated Daphnia pulex and Moina macrocopa within 24 hours when concentrations were equal to or exceeded 6 mg/L. Moreover, supplying C9-biosurfactant into the cultures of selected algal species with and without cladoceran grazers indicated no adverse effect of C9-biosurfactant on the growth and lipid productivity of algal crops, while cladocerans were selectively controlled by C9-biosurfactant even under the presence of their prey. These results thus indicate that C9-biosurfactant could be an effective biocontrol agent for cladoceran grazers at industrial algal cultivation.

Synergistic Inhibitory Activity of Bacillomycin D, Surfactin and Nisin against Thermoascus crustaceus, Neosartorya hiratsukae and Bacillus subtilis, Responsible for Cardboard Spoilage

“…The mass spectra of fraction 2 showed intense mass peaks at masses 1030.63, 1044.65 and 1058.67 which were attributed to sodium adducts of C13 surfactin, C14 surfactin and C15 surfactin, when compared with published studies 25 . Protonated peaks [M+H] + were present at m/z values 1008.63, 1022.65 and 1036.67, which differed by a mass difference of 14, corresponding to -CH 2 group.…”

Identification of Loliolide with Anti-Aging Properties from Scenedesmus deserticola JD052

“…Scenedesmus deserticola JD052 was cultured in BG11 medium in a 5 L photo-bioreactor (Sigma Aldrich, USA) for 7 days at 25°C, under continuous light (150 μmol m -2 s -1 ) [ 15 ] and an equivolume of the cellular culture was then divided into three photobioreactors. While one of three PBRs was maintained under the identical light condition as the preceding cultivation period, two reactors were subjected to post-treatment either under high light intensity (1,200 μmol m -2 s -1 ) or UVB radiation (30 μmol m -2 s -1 ) for 12 h to elucidate the influence of each post-treatment on the accumulation of anti-UV compounds.…”

Biotechnologies for bulk production of microalgal biomass: from mass cultivation to dried biomass acquisition

“…They usually act as predators of microalgae, reducing algal concentration and production to low levels in few days. The common predatory species in the microalgal mass cultivation are ciliate [ 127 ], rotifer [ 109 ], cladocera [ 128 ], and copepod [ 129 ]. A study has reported that the presence of Brachionus rubens reduced the biomass production of C. sorokiniana by up to 99.8%, leading to the collapse of the algal culture [ 107 ].…”