Resistance of Neochloris oleoabundans to six terpenes applicable as green contamination control agents

Microalgae are emerging sources for sustainable production of bioproducts and bioenergy. However, a problem with its reliable production is the biological contamination of cultures. There are several alternatives to mitigate this problem, such as using axenic cultures, concentrated inocula, or applying chemical control agents, which should be eco-friendly. Neochloris oleoabundans is an oleaginous green microalga with a high potential for biofuel production due to its ability to accumulate neutral lipids, mainly monounsaturated fatty acids. For this reason, the main objective of this article was to evaluate the toxicity of 6 natural terpenes with proven antibacterial activity (α-pinene, β-pinene, limonene, trans-cinnamaldehyde, linalool, and eugenol) towards cultures of this green microalgae, through toxicity analysis to obtain the lethal concentration 50 (LC50). The values for β-pinene and limonene were 17 and 16 ppm, respectively, lower than the levels obtained for α-pinene and trans-cinnamaldehyde, of 65 and 35 ppm, respectively. Eugenol and linalool showed LC50 levels above 250 ppm. These results show that selected terpenes do not present high toxicity against N. oleoabundans. Therefore, they can be a green alternative in the management of the cultures.