Physiological response of the green microalgae Dunaliella tertiolecta against imidazolium ionic liquids [bmim][BF4] and/or [omim][BF4]: the role of salinity on the observed effects

Abstract

The ability of two widely used imidazolium-based ionic liquids (ILs) to affect the physiological behavior of the green alga Dunaliella tertiolecta treated in culture media with different salinities (30 and 35‰) was investigated. Algae species were exposed to 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF 4 ]), 1-octyl-3-methylimidazolium tetrafluoroborate ([omim][BF 4 ]), and their binary mixture [bmim][BF 4 ]-[omim][BF 4 ] (ratio 1:1) for 96 h, in f/2 medium with different salinities (30 and 35‰). Every 24 h, the growth rate (μ) and the percent inhibition (% I) as well as the concentrations of carotenoids (in terms of carotene content) and chlorophyll a (Chl a) were determined. According to the results, the culture media salinity plays a key role in IL-mediated inhibitory effects on algae. In both salinities, ILs can act against algal growth rate rather than Chl a synthesis, merely due to the existence of a cross-linking with carotenoids, whose enhancement prior or in parallel with Chl a synthesis could play an important role against their growth restriction.

Effect of Organic Solvents on Microalgae Growth, Metabolism and Industrial Bioproduct Extraction: A Review

“…IL molecules consist of the cationic and the anionic part [ 47 , 110 , 111 , 112 , 113 , 114 , 115 , 116 , 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 ]. ILs containing cations in a form of imidazolium (IM), pyrrolidinium (Pyr[r]) or pyridinium (Py) rings, that possess alkyl and methyl side groups (1-alkyl-3-methylimidazolium, [C n MIM] + ; 1-alkyl-1-methylpyrrolidinium, [C n MPyrr] + ; 1-alkyl-3-methylpyridinium, [C n MPy] + ).…”

“…Alkyl chain of cation group plays an important role in toxicity of ILs. Inhibitory ability of ILs increases when the alkyl chain of the cation part is longer due to increased chain lipophilicity, thereby interacting with phospholipid bilayers or hydrophobic domains of membrane proteins, causing alterations in cell membranes and an increase in membrane permeability [ 113 ]. For example, [C 8 MIM]BF 4 showed a few orders higher toxicity against Scenedesmus rubescens , than [C 4 MIM]BF 4 [ 114 ].…”

“…Increase in salinity was reported to decrease inhibitory effect of [C n MIM]Cl on Chlorella , Oocystis and Cyclotella growth, due to complexation of inorganic anions and alkylimidazolium cations, resulting in a limited contact between ILs and microalgal cell surface [ 127 ]. A change in salinity also influenced the effect of [C n MIM]BF 4 on Dunaliella tertiolecta growth, as well as carotenoid and chlorophyll a content in cells [ 113 ]. On the other hand, a decrease in salinity did not alter the effect of [C 4 MIM]Cl on Skeletonema marinoi [ 128 ].…”

“…Chlorophyll and carotenoid contents were also reported to increase in Dunaliella tertiolecta cells exposed to ILs. Those pigments possess antioxidant properties, and they can be thus synthetized in abundance to cope with oxidative stress [ 113 ]. Euglena gracilis , a strain capable of alterating cell shape, was observed to release chloroplasts and shift its growth towards heterotrophism, upon exposure to ILs [ 123 ].…”

Effects of imidazolium chloride ionic liquids and their toxicity to Scenedesmus obliquus

“…systems (Deng et al, 2015;Kumar et al, 2011) and the enantioselective toxicities of chiral ILs to aquatic algae (Chen et al, 2014). The role of carrier solvent (acetone, salinity) on the induced toxicity, and the binary mixture of ILs were studied (Tsarpali et al, 2015a(Tsarpali et al, , 2015bTsarpali and Dailianis, 2015). The quantitative structure-activity relationship (QSAR) was also adopted to study the toxicity of ILs (Das andRoy, 2014, Peric et al, 2015).…”