Effect of Mixotrophy on Lipid Content and Fatty Acids Methyl Esters Profile by Chromochloris zofingiensis Grown in Media Containing Sugarcane Molasses

Lipid content and fatty acid methyl ester profile by Chromochloris zofingiensis under chemical and metabolic stress

“…A relationship between dried biomass concentration and ABS was established by building a regression equation, which allowed calculating the biomass of the sample once obtained the value of ABS reading. The detailed procedure adopted for the gravimetrical determination of the dry biomass has been reported in a previous work carried out by our team [22].…”

“…The latter were collected and freeze-dried at − 80 °C for about 24 h. The extraction of lipids was carried out on the freeze-dried biomass which had been previously lyophilized (Lio1000P, 5 Pascal, Trezzano s/N, MI, Italy). The detailed steps of the lyophilization process are reported in Vitali et al [22]. Broadly, two extractive solutions are required, one chloroform/methanol mix and a chloroform + sodium chloride solution, which contribute to get a final volume ratio of about 2:2:1.8 (chloroform/ methanol/water).…”

“…A modified protocol reported by Lage and Gentili [34] was adopted for FAME determination starting from lyophilized biomass. The detailed procedure is reported in Vitali et al [22]. Briefly, toluene and 1% H 2 SO 4 in anhydrous methanol were used to improve the methylation of non-polar lipids and their trans-methylation, respectively.…”

“…The extraction of FAMEs was then performed with a 5% NaCl + hexane extractive solution, and after phase separation, the organic phase was quantitatively analyzed by a 7820A Gas Chromatograph (Agilent Technologies, Palo Alto, CA, USA) coupled to a 5977B Mass Spectrometer (Agilent Technologies, Palo Alto, CA, USA). Data on GC-MS system, capillary column, gas carrier, injector, and detector temperature as well as mode of operation for the chromatogram were reported elsewhere [22]. The individual FAMEs were identified and quantified by using a standard reference solution based on a Supelco 37 Component FAME Mix® (Sigma-Aldrich, Saint Louis, MO, USA), tricosanoic acid methyl ester (TAME) internal standard solution, and hexane.…”

“…Besides the production of the carotenoid astaxanthin, C. zofingiensis emerges as a potential accumulator of lipids for the production of biodiesel when exposed to suitable stressful conditions such as high light [20] and nitrogen deprivation [21]. Another appealing aspect noteworthy is the ability of C. zofingiensis to modulate its metabolism shifting from an initial photoautotrophy or heterotrophy into a mixotrophic mode, increasing in this way the production of biomass and lipids by coupling two different trophic modes of cell growth [22,23]. Therefore, based on its ability to growth under these multitrophic culture conditions as well as on its high-density growth, scalability, and tolerance to a wide range of environmental stresses (primarily pathogens and pollutants), C. zofinginesis can represent a desirable robust strain for biotechnological applications [18,24,25].…”