New at-line flow cytometric protocols for determining carotenoid content and cell viability during Rhodosporidium toruloides NCYC 921 batch growth

Abstract

a b s t r a c tRhodosporidium toruloides NCYC 921 batch growth was monitored as a means to evaluate the yeast biomass potential as a source for the production of carotenoids and other lipids.Carotenoid content, cell viability and size were assessed by multiparameter flow cytometry. The saponifiable lipid fraction was assayed by gas-liquid chromatography.The carotenoid production increased during the stationary phase, reaching 78 g/g while the total fatty acid content attained 32% (w/w) at the end of the fermentation. The fatty acid profile was suitable for biodiesel purposes.As the yeast cells entered the stationary phase, the proportion of cells with depolarised mitochondrial membrane and cells with permeabilised cytoplasmic membrane increased, attaining 65% and 14%, respectively. Nevertheless, a high proportion of cells (82%) showed esterase activity.These results demonstrated that flow cytometry can be a powerful at-line technique to monitor the total carotenoids and cell viability during the yeast growth, being useful for the yeast process optimisation at lab and pilot scales.

Combined mutagenesis of Rhodosporidium toruloides for improved production of carotenoids and lipids

“…More interestingly, wild-type R. toruloides also produces carotenoids that give colonies a red phenotype. As carotenoids are high value products, co-production of carotenoids may contribute to improve the technoeconomics of microbial lipid technology (Parreira et al 2015;Freitas et al 2014). Indeed, a few attempts have employed Rhodosporidium and related genera for production of carotenoids which are useful as natural food colorants and feed additives in aqua culture (Nasrabadi and Razavi 2011;Ruhiyat et al 2015).…”

A new combined approach to improved lipid production using a strictly aerobic and oleaginous yeast

“…toruloides CECT 1499 (this study), R. toruloides Y4[13], R. toruloides NCYC 921[67], R. glutinis/S. toruloides CECT 1499 (this study), R. toruloides Y4[13], R. toruloides NCYC 921[67], R. glutinis/S.…”

Role of flow cytometry for the improvement of bioprocessing of oleaginous microorganisms

“…It has been recommended that FSC and SSC scattering can be potentially used to monitor microbial physiological state. Two different studies reported the physiological state of R. glutinis and R. toruloides using flow cytometry . During the exponential phase of the cultivation, two well‐defined individual peaks were observed in the FSC/SSC plot for R. glutinis , one peak indicating the matured cells and another indicating budding cells while average fluorescent reading of FSC/SSC was increased for R. toruloides but no division in the major peak.…”

“…That is, during exponential phase, the budding pattern and proportion of R. glutinis differ from R. toruloides . Therefore, the average and pattern of FSC/SSC signals for exponential phase (of both R. glutinis and R. toruloides ) was a balance between the proportion of budding cells and new small cells . Since it is hard to conclude how a cell can behave at a particular growth phase, it is important to carry out the correct control experiments for each organism analysed.…”

“…In addition to lipid content, cell size and viability determination in oleaginous yeast, estimation of carotenoid content was also successfully demonstrated in pink yeast R. toruloides by FACS Calibur (BD, Franklin Lakes, NJ). R. toruloides is well known for the production of β‐carotene, torulene, and torularhodin . Since carotenoid can emit autofluorescence, all four detector channels FL1, FL2, FL3, and FL4 were used for the measurement of autofluorescence in R. toruloides .…”