RESPONSE OF TRACHYDISCUS MINUTUS (XANTHOPHYCEAE) TO TEMPERATURE AND LIGHT¹

Abstract

The effects of different temperatures and light intensities on growth, pigments, sugars, lipids, and proteins, as well as on some antioxidant and proteolytic enzymes of Trachydiscus minutus (Bourr.) H. Ettl, were investigated. The optimum growth temperature and light intensity were 25°C and 2 × 132 μmol photons · m(-2 ) · s(-1) , respectively. Under these conditions, proteins were the main biomass components (33.45% dry weight [dwt]), with high levels of carbohydrates (29% dwt) and lipids (21.77% dwt). T. minutus tolerated temperatures between 20°C and 32°C, with only moderate changes in cell growth and biochemical composition. Extremely low (15°C) and high (40°C) temperatures decreased chl and RUBISCO contents and inhibited cell growth. The biochemical response of the alga to both unfavorable conditions was an increase in lipid content (up to 35.19% dwt) and a decrease in carbohydrates (down to 13.64% dwt) with much less of a change in total protein content (in the range of 30.51%-38.13% dwt). At the same time, the defense system of T. minutus was regulated differently in response to heat or cold treatments. Generally, at 40°C, the activities of superoxide dismutase (SOD), catalase (CAT), and proteases were drastically elevated, and three polypeptides were overexpressed, whereas the glutathione reductase (GR) and peroxidase (POD) activities were reduced. In contrast, at 15°C, all these enzymes except GR were suppressed. The effect of light was to enhance or decrease the temperature stress responses, depending on intensity. Our studies demonstrate the broad temperature adaptability of T. minutus as well as the potential for the production of valuable algal biomass.

Trace concentrations of iron nanoparticles cause overproduction of biomass and lipids during cultivation of cyanobacteria and microalgae

“…Similar values were obtained by Gigova et al (2012) who studied the effect of temperature and light intensity on the same T. minutus strain. They reported that low temperature (about 15°C), which represents a stress condition for this microorganism, increased lipid accumulation to 35 %.…”

“…They reported that low temperature (about 15°C), which represents a stress condition for this microorganism, increased lipid accumulation to 35 %. On the other hand, pronounced growth inhibition was found under these conditions (Gigova et al 2012).…”

Accumulation of energy reserves in algae: From cell cycles to biotechnological applications

“…In Scenedesmus obliquus, the final lipid store content varied between 18% and 40% of DW at temperatures between 20 o C and 27.5 o C. In general, storage starch and lipids are synthesized at all temperatures in the suboptimal range, but the final lipid or starch content is highest at the optimal temperatures favored for biomass growth (Breuer et al, 2013;Gigova et al, 2012;Roleda et al, 2013).…”

Microalgae as a Feedstock for Biofuel Precursors and Value-Added Products: Green Fuels and Golden Opportunities

“…RuBisCO; see Nakamura and Miyachi 1982b). Although the detailed effect of temperature on carbohydrate content remains unclear, a few authors demonstrated a stimulation of carbohydrate synthesis when the temperature was increased to an optimal range (Oliveira et al 1999;Gigova et al 2012). On the other hand, Renaud et al (2002) reported a lack of relation between temperature and carbohydrate contents for Isochrysis sp., Rhodomonas sp., Cryptomonas sp., Chaetoceros sp., and Prymnesiophyte alga.…”