Production of β-Carotene by a Newly Isolated Rhodotorula Glutinis UCP1555 Strain and Cytotoxic Effect Evaluation

Carotenoids have attracted greater attention due to the beneficial role on human health. It is an essential nutrient and has some biological functions such as species-specific coloration, photoprotection, light absorbing, which is an important component because of its role as precursor of vitamin A. In this study was performed the production of fl-Carotene by Rhodotorula glutinis UCP/WFCC 1555 in presence and absence of blue and white using LED （light-emitting diodes） and evaluation of the cytotoxic effect. The production was investigated in low cost medium constituted by different concentrations of CG （crude glycerin） and CSL （corn steep liquor） from the CCD （Central Composite Design） and the identification and yield of the β-Carotene was investigated by chromatographic profile （HPLC）. Additionally, the fl-Carotene produced was tested to evaluate its cytotoxic effect in human tumor cells MCF-7 （breast cancer） and HL-60 （promyelocytic leukemia） and healthy cells of macrophages. The results showed that in the medium composed by 6% glycerin and 0.6% corn steep liquor, in the absence of light, occurred the maximum production of total carotenoids with values of 160μg·g-1 and these 100.60μg·g-1 correspond to the β-Carotene that showed ability in inhibit cell growth in several tumor cells such as MCF-7 cells （breast cancer） and HL-60 （promyelocytic leukemia）.

Influence of Agitation and Aeration on Single Cell Oil Production by Rhodotorula glutinis from Glycerol

In the present study, the yeast Rhodotorula glutinis has been assessed with the aim of producing microbial lipids from glycerol under different aeration conditions. For such a purpose, experiments were carried out in shake flasks, under different conditions of agitation (150 to 250 rpm) and aeration (2.5 to 5.0 of flask volume-to-medium volume ratio). Furthermore, their influence on fermentative parameters (lipid and cell concentration, biomass yield;lipid yield;and lipid volumetric productivity) has been investigated using a 22 full factorial design. The statistical analysis has revealed a strong influence of both variables on substrate consumption, lipid accumulation, cell growth and lipid productivity. As a whole, results suggest that higher aeration levels provide greater cell and lipid concentrations, and lipid volumetric productivity. The best results (4.5 g/L of lipids and QP = 0.95 g/L⋅day) were achieved at the highest aeration (5.0 flask volume-to-medium volume ratio) and agitation (250 rpm) levels. Their fatty acid profile showed that oleic acid was produced in greater quantity (53.5%), followed by linoleic acid (18.7%), palmitic acid (6.8%) and stearic acid (9.9%). The microbial oil presented viscosity of 39.3 cP at 50°C and free fatty acid content of 1.93% ± 0.08%. These are significant results and contribute to establishing operational conditions that maximize single-cell oil production from glycerol by Rhodotorula glutinis, i.e. an alternative source as renewable raw material for lipid-based biorefineries.

Utilization of Soluble Starch by Oleaginous Red Yeast Rhodotorula glutinis

Starch containing wastewaters from the food and feed industry have been identified as potential cheap carbon sources for the production of microbial lipids. Due to its high potential lipid content the oleaginous yeast Rhodotorula glutinis is often used for fermentations in this field. Moreover it is investigated in the context of microbial carotenoid production, which also requires a cheap source of carbon. Thus, the ability of R. glutinis (ATCC 15125TM) to degrade and utilize soluble starch for the production of lipids has been assessed in this study. While glucose and fructose were readily consumed from the medium, starch was only slightly reduced in one treatment. The yield of fatty acid methyl esters (FAME) was graduated corresponding to the initial sugar contents, with the highest FAME yield (1.5 g·L-1) at the highest initial sugar content. In the treatment that contained starch as single carbon source, no FAME production was realized. Accordingly, if starchy wastewaters should be used for microbial cultivation with R. glutinis, an enzymatic or chemical pretreatment for starch hydrolysis should be applied, to increase the availability of this carbon source.

Biocontrol Efficacy of Three Antagonistic Yeasts Against Penicillium expansum in Harvested Apple Fruits

Three antagonistic yeasts, Trichosporon pullulans (Lindner.) Diddens and Lodder, Cryptococcus laurentii (Kuffer.) Skinner and Rhodotorula glutinis (Fresen.) F. C. Harrison, selected from over 50 yeasts on apple fruits, were investigated of their biocontrol efficacy against blue mould rot caused by Penicillium expansum Link in apple fruits. T. pullulans was identified to be a new yeast antagonist and was the most effective at inhibiting blue mould rot in the three yeasts. The effects of different concentrations of the three yeasts and addition Of nutrients, as well as combination with calcium on controlling blue mould rot in apples were presented in the paper. The results indicated that the higher the yeast concentrations, the more effective the yeasts on biocontrol activity. Addition of nutrients reduced the biocontrol capacity of the yeasts. Combination of 0.18 mol/L CaCl2 with C. laurentii cell suspensions could significantly enhance its effect to P. expansum in apple fruits, while the efficacy of calcium on biocontrol activity of T. pullulans or R. glutinis was not remarkable.