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The main objective of this study was to investigate culture substrates, stress conditions and cold-adaptive cellular lipid products of potential industrial interest associated with the short-term environmental adaptation by an Antarctic snow microalga. Viable culture lines of the Antarctic snow microalga Chlamydomonas sp. (DPA-02 strain) were obtained after two years storage period at -4 oC without light source. The dark- adapted Chlamydomonas sp. exhibited high sensitivity to light, growing optimally on Bristol media under a light level of 10 μmol m-2 s-1 and a temperature of 12 ± 2°C. The snow microalga yielded 93% of its lipid content as saturated fatty acids, 67% of which was palmitic acid (C16:0). The study also showed the significant alteration of the microalga’s lipid profile by modifying the culture’s growing conditions, resulting in a significant increase in PUFA’s independently of the culture temperature, from about 10% to 70%, when the culture was subjected to continuous darkness over a one-month period. The growth rate of the microalga decreased with increase in NaCl concentration in the growing medium. Further, the microalga was found to be sensitive to the physical matrix on which it grew, showing a higher mortality rate when exposed to a low-temperature shock on a solid medium different than snow or ice. These results provided unprecedented insights into cryoprotective strategies employed by snow microalgae to survive under the severe environmental conditions of Antarctica.

The main objective of this study was to investigate culture substrates, stress conditions and cold-adaptive cellular lipid products of potential industrial interest associated with the short-term environmental adaptation by an Antarctic snow microalga. Viable culture lines of the Antarctic snow microalga Chlamydomonas sp. (DPA-02 strain) were obtained after two years storage period at -4 oC without light source. The dark- adapted Chlamydomonas sp. exhibited high sensitivity to light, growing optimally on Bristol media under a light level of 10 μmol m-2 s-1 and a temperature of 12 ± 2°C. The snow microalga yielded 93% of its lipid content as saturated fatty acids, 67% of which was palmitic acid (C16:0). The study also showed the significant alteration of the microalga’s lipid profile by modifying the culture’s growing conditions, resulting in a significant increase in PUFA’s independently of the culture temperature, from about 10% to 70%, when the culture was subjected to continuous darkness over a one-month period. The growth rate of the microalga decreased with increase in NaCl concentration in the growing medium. Further, the microalga was found to be sensitive to the physical matrix on which it grew, showing a higher mortality rate when exposed to a low-temperature shock on a solid medium different than snow or ice. These results provided unprecedented insights into cryoprotective strategies employed by snow microalgae to survive under the severe environmental conditions of Antarctica. Resumen: El principal objetivo de este estudio fue investigar la variación de lípidos totales en relación a la adaptación al frío, sustratos de cultivo y condiciones de estrés, intentando homologar la adaptación ambiental a corto plazo de microalgas antárticas fotosintéticas. Cultivos de la microalga de nieve antártica Chlamydomonas sp. (cepa DPA-02) fueron obtenidos después de dos años de almacenamiento a -4°C y sin fuente de luz. Chlamydomonas sp. (DPA-02) exhibió alta fotosensibilidad, creciendo óptimamente en medio Bristol bajo un nivel de luz de 10 μmol m-2 s-1 y una temperatura de 12 ± 2°C. Las microalgas de las nieves produjeron el 93% de su contenido de lípidos como ácidos grasos saturados, el 67% de los cuales era ácido palmítico (C16:0). El estudio también mostró la alteración significativa del perfil lipídico de la microalga al modificar las condiciones de crecimiento del cultivo, resultando en un aumento significativo de PUFAs independientemente de la temperatura del cultivo, este incremento fue desde un 10% a un 70% aproximadamente cuando el cultivo fue sometido a oscuridad continua durante un período de tiempo de un mes. Adicionalmente, la tasa de crecimiento de la microalga disminuyó con el aumento de la concentración de NaCl en el medio de cultivo. Igualmente, se encontró que la microalga era sensible a la matriz física en la que crecía, mostrando una mayor tasa de mortalidad cuando se exponía a un shock de baja temperatura en un medio sólido distinto de la nieve o el hielo. Estos resultados proporcionan nuevos antecedentes sobre las estrategias crio- protectoras empleadas por microalgas de nieve para sobrevivir bajo las severas condiciones ambientales de la Antártida.

Smarandache's function is defined thus:S( n) = is the smallest integer such that S( n)! is divisible by n.