Effect of aeration on the production of carotenoid pigments by Rhodotorula rubra-lactobacillus casei subsp. casei co-cultures in whey ultrafiltrate

Under intensive aeration (1.3 l/l min) the associated growth of Rhodotorula rubra GED2 and Lactobacillus casei subsp. casei in cheese whey ultrafiltrate (55 g lactose/l) proceeded effectively for both cultures with production of maximum carotenoids (12.4 mg/l culture fluid). For maximum amount of carotenoids synthesized in the cell, the yeast required more intensive aeration than the aeration needed for synthesis of maximum concentration of dry cells. Maximum concentration of carotenoids in the cell (0.49 mg/g dry cells) was registered with air flow rate at 1.3 l/l min, and of dry cells (27.0 g/l) at 1.0 l/l min. An important characteristic of carotenogenesis by Rhodotorula rubra GED2 + Lactobacillus casei subsp. casei was established--the intensive aeration (above 1.0 l/l min) stimulated beta-carotene synthesis (60% of total carotenoids).     

Beta-carotene-rich carotenoid-protein preparation and exopolysaccharide production by Rhodotorula rubra GED8 grown with a yogurt starter culture

The underlying method for obtaining a beta-carotene-rich carotenoid-protein preparation and exopolysaccharides is the associated cultivation of the carotenoid-synthesizing lactose-negative yeast strain Rhodotorula rubra GED8 with the yogurt starter culture (Lactobacillus bulgaricus 2-11 + Streptococcus thermophilus 15HA) in whey ultrafiltrate (45 g lactose/l) with a maximum carotenoid yield of 13.37 mg/l culture fluid on the 4.5th day. The chemical composition of the carotenoid-protein preparation has been identified. The respective carotenoid and protein content is 497.4 microg/g dry cells and 50.3% per dry weight, respectively. An important characteristic of the carotenoid composition is the high percentage (51.1%) of beta-carotene (a carotenoid pigment with the highest provitamin A activity) as compared to 12.9% and 33.7%, respectively, for the other two individual pigments--torulene and torularhodin. Exopolysaccharides (12.8 g/l) synthesized by the yeast and lactic acid cultures, identified as acid biopolymers containing 7.2% glucuronic acid, were isolated in the cell-free supernatant. Mannose, produced exclusively by the yeast, predominated in the neutral carbohydrate biopolymer component (76%). The mixed cultivation of R. rubra GED8 with the yogurt starter (L. bulgaricus 2-11 + S. thermophilus 15HA) in ultrafiltrate under conditions of intracellular production of maximum amount of carotenoids and exopolysaccharides synthesis enables combined utilization of the culture fluid from the fermentation process.     

Synthesis of carotenoids by<Emphasis Type="Italic"> Rhodotorula rubra</Emphasis> GED8 co-cultured with yogurt starter cultures in whey ultrafiltrate

Two cultures, a yeast (Rhodorula rubra GED8) and a yogurt starter (Lactobacillus bulgaricus 2–11+Streptococcus thermophilus 15HA), were selected for associated growth in whey ultrafiltrate (WU) and active synthesis of carotenoids. In associated cultivation with the yogurt culture L bulgaricus 2–11+S. thermophilus 15HA under intensive aeration (1.3 l^–1min^–1 air-flow rate) in WU (45 g lactose l^–1), initial pH 5.5, 30 °C, the lactose-negative strain R. rubra GED8 synthesized large amounts of carotenoids (13.09 mg l^–1 culture fluid). The carotenoid yield was approximately two-fold higher in association with a mixed yogurt culture than in association with pure yogurt bacteria. The major carotenoid pigments comprising the total carotenoids were -carotene (50%), torulene (12.3%) and torularhodin (35.2%). Carotenoids with a high -carotene content were produced by the microbial association 36 h earlier than by Rhodotorula yeast species. No significant differences were notd in the ratio between the pigments synthesized by R. rubra GED8+L. bulgaricus 2–11, R. rubra GED8+S. thermophilus 15HA, and R.rubra GED8+yogurt culture, despite the fact that the total carotenoid concentrations were lower in the mixed cultures with pure yogurt bacteria.     

Exopolysaccharides produced by mixed culture of yeast Rhodotorula rubra GED10 and yogurt bacteria (Streptococcus thermophilus 13a + Lactobacillus bulgaricus 2-11)

AIMs: The studies of the production of exopolysaccharides by lactose-negative yeast and a yogurt starter co-cultivated in a natural substrate containing lactose may be considered of interest because they reveal the possibilities for high-efficiency synthesis of biopolymers by mixed cultivation. METHODS AND RESULTS: The mixed culture Rhodotorula rubra GED10 + (Streptococcus thermophilus 13a + Lactobacillus bulgaricus 2-11) was cultivated in cheese whey ultrafiltrate (WU) (44.0 g lactose l(-1)) at initial pH 6.0, 28 degrees C, under intensive aeration (air-flow rate 1.0 l l(-1) min(-1), agitation 220 rev min(-1)) in a MBR AG fermentor. The mixed culture manifested the highest activity for synthesis of exopolysaccharides (19.3 g l(-1)) and cell mass (21.0 g l(-1)) at the 84th hour. The yogurt starter synthesized neutral exopolysaccharides, while the mixed culture yeast + yogurt starter produced acidic exopolysaccharides containing uronic acid (6%). The neutral sugar composition was identified as mannose, glucose, galactose, xylose and arabinose. Mannose dominated in the polymer composition (83%) that was produced only by the yeast (97%). CONCLUSIONS: Lactose in the WU can be effectively utilized by a co-culture of lactose-negative yeast-yogurt starter for synthesis of exopolysaccharides. SIGNIFICANCE AND IMPACT OF THE STUDY: The present findings propose an alternative use of WU as a cost-effective carbohydrate substrate, and suggest that the lactose-negative yeast Rhodotorula rubra can have industrial application as producers of exopolysaccharides.     

Production of β-carotene by a mutant of Rhodotorula glutinis

Wild strains of Rhodotorula glutinis and R. rubra were investigated concerning their carotenoid production, proportion of beta-carotene and cell mass yield. R. glutinis NCIM 3353 produced 2.2 mg carotenoid/l in 72 h; and the amount of beta-carotene was 14% (w/w) of the total carotenoid content (17 microg/g cell dry weight). It was subjected to mutagenesis using UV radiation for strain improvement. Out of 2,051 isolates screened, the yellow coloured mutant 32 produced 120-fold more beta-carotene (2,048 microg/g cell dry weight) than the parent culture in 36 h, which was 82% (w/w) of the total carotenoid content. Mutant 32 was grown on different carbon and nitrogen sources. The best yield of beta-carotene (33+/-3 mg/l) was obtained when glucose and yeast extract were supplied as carbon and nitrogen sources, respectively. Divalent cation salts further increased the total carotenoid content (66+/-2 mg/l) with beta-carotene as the major component (55+/-2%, w/w).     

Effects of different fungal elicitors on growth, total carotenoids and astaxanthin formation by Xanthophyllomyces dendrorhous

Six fungal elicitors prepared from Rhodotorula rubra, Rhodotorula glutinis, Panus conchatus, Coriolus versicolor, Mucor mucedo, Mortieralla alpina M-23 were examined to determine their effects on the growth, total carotenoids and astaxanthin formation by Xanthophyllomyces dendrorhous. The results showed that different fungal elicitor could cause diversely stimulating effects. Among the fungal elicitors tested, the M. mucedo elicitor concentration of 30 mg l(-1) promoted the biomass and total carotenoids yield most remarkably, resulting in 69.81+/-6.00% and 78.87+/-4.15% higher than the control, respectively. At the concentration of 30 mg l(-1), R. glutinis elicitor stimulated the highest astaxanthin yield with a 90.60+/-5.98% increase compared to the control. The R. rubra elicitor concentration of 30 mg l(-1) resulted in the optimal total carotenoids and astaxanthin content to be 42.24+/-0.49% and 69.02+/-0.72% higher than the control, respectively. At the concentration of 30 mg l(-1), R. rubra elicitor gave the highest increase in the ratio of astaxanthin in total carotenoids by 18.85+/-0.11% of the control.     

The subcellular distribution of carotenoids in light-grown Verticillium agaricinum

Hyphae of light-grown V. agaricinum (Link) Corda contain many lipid bodies. The hypae were disrupted and the membranes immediately pelleted by a 48 000 g spin for 30 min. The major part (90%) of the carotenoids was found in a lipid layer on top of the supernatant. Carotenoids extracted from the lipid layer in diethyl ether had an absorption maximum at 488 nm. On the basis of spectra in different organic solvents the main component was tentatively. Thin layer chromatography of extracted and saponified carotenoids revealed the presence of one major and one minor component.
The 48 000 g pellet contained 80% of the NAD⁺-dependent malate dehydrogenase (marker for mitrochondria), 25% of the antimycin-resistant NADH-cytochrome c reductase (marker for mitochodria and endoplasmic reticulum) and 10% of the proteins and the carotenoids. The latter were different from the carotenoids in the lipid layer in that the absorption maximum was at 471 nm in diethyl ether.
Further fractionation of the 48 000 g pellet showed the presence of carotenoids in both mitochondria and endoplasmic reticulum (ER) all with an absorption maximum at 471 nm. On a thin layer plate these carotenoids migrated in one band coinciding with the minor band of the lipid layer. On a continous Percoll gradient two main areas of mitochodrial activity (1.068 and 1.063 g ml⁻¹) were clearly separated from the ER (1.059 g ml⁻¹). The carotenoid content was about 0.6 and 0.7–1.0 μg (mg protein)⁻¹ for mitochondria and ER, respectively, equivalent to 1–2 carotenoid molecules per 1000 lipid molecules. The possible role of these membrane-bound carotenoid molecules is discussed.     

Production of beta-carotene by a Rhodotorula glutinis mutant in sea water medium

Mutant 32, derived from Rhodotorula glutinis NCIM 3353 produced 76-fold more beta-carotene than the parent strain. In the growth medium prepared in seawater, the total carotenoid content and dry cell mass was 86 mg/l and 16 g/l, respectively, as compared to 70 mg/l and 12 g/l obtained with a medium prepared in distilled water. A 2-fold increase in beta-carotene with simultaneous 2.3-fold decrease in torulene content was also observed. When grown in seawater medium at pH 6.0, 83 +/- 5% carotenoids could be extracted from the cells without any mechanical disintegration.     

Improvement of carotenoid-synthesizing yeast Rhodotorula rubra by chemical mutagenesis

A mutant Rhodotorula rubra with enhanced carotenoid-synthesizing activity for synthesizing total carotenoids and beta-carotene was obtained by N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis. When co-cultivated with yogurt starter bacteria (Lactobacillus bulgaricus + Streptococcus thermophilus) in whey ultrafiltrate it produced 15.7 mg total carotenoids l(-1) culture fluid or 946 microg total carotenoids g(-1) dry cells of which 71% was beta-carotene. Grown as a monoculture in glucose substrate, the mutant shown 1.4 times lower carotenoid-synthesizing activity, and the relative share of beta-carotene in the total carotenoids was lower (63%). The individual pigments torulene and torularhodin were identified, whose mass fractions were (29% and 7%) and (24% and 4%), respectively, for the mutant grown as a monoculture and as a mixed culture with the yogurt bacteria.     

Effect of temperature changes on the production of yeast pigments co-cultivated with lacto-acid bacteria in whey ultrafiltrate

Rhodotorula glutinis 22P when co-cultivated with Lactobacillus helveticus 12A in a whey ultrafiltrate synthesizes maximum cell mass and carotenoid concentrations (31.9 g/l and 8388 g/l, respectively) at 30°C. The change in the growth temperature conditions of both cultures influences the carotenogenesis by yeast and the proportion of individual pigments forming up the carotenoids.     

Metabolic engineering of high carotenoid potato tubers containing enhanced levels of beta-carotene and lutein

In order to enhance the carotenoid content of potato tubers, transgenic potato plants have been produced expressing an Erwinia uredovora crtB gene encoding phytoene synthase, specifically in the tuber of Solanum tuberosum L. cultivar Desiree which normally produces tubers containing c. 5.6 microg carotenoid g(-1) DW and also in Solanum phureja L. cv. Mayan Gold which has a tuber carotenoid content of typically 20 microg carotenoid g(-1) DW. In developing tubers of transgenic crtB Desiree lines, carotenoid levels reached 35 microg carotenoid g(-1) DW and the balance of carotenoids changed radically compared with controls: beta-carotene levels in the transgenic tubers reached c. 11 microg g(-1) DW, whereas control tubers contained negligible amounts and lutein accumulated to a level 19-fold higher than empty-vector transformed controls. The crtB gene was also transformed into S. phureja (cv. Mayan Gold), again resulting in an increase in total carotenoid content to 78 microg carotenoid g(-1) DW in the most affected transgenic line. In these tubers, the major carotenoids were violaxanthin, lutein, antheraxanthin, and beta-carotene. No increases in expression levels of the major carotenoid biosynthetic genes could be detected in the transgenic tubers, despite the large increase in carotenoid accumulation. Microarray analysis was used to identify a number of genes that were consistently up- or down-regulated in transgenic crtB tubers compared with empty vector controls. The implications of these data from a nutritional standpoint and for further modifications of tuber carotenoid content are discussed.     

Responses of Chlorophyll Fluorescence and Carotenoids Biosynthesis to High Light Stress in Rice Seedling Leaves at Different Leaf Position

In the present study, we investigated the changes of photosynthesis, chlorophyll fluorescence and the content of carotenoid pigments in rice ( Oryza sativa L.) seedling leaves and their responses to high light. The results showed that the rate of photosynthesis, the contents of individual and total carotenoids and the pool size of xanthophyll cycle decreased with age increasing of the leaf. When the leaves were exposed to high light for 2 h, the qN of mature leaf (5th leaf) increased more significantly than that of younger (6th leaf) and older leaves (3rd and 4th leaf). Comparing with the leaves before exposure to high light, the excitation pressure on PSⅡ (1-qP) increased by 44%, 57%, 19% and 45% in the 3rd, 4th, 5th and 6th leaf under high light, respectively. The highest content of carotenoids and the greatest conversion of violaxanthin to zeaxanthin were found in the 5th leaf, and it was consistent with the 5th leaf exhibiting the strongest resistance to high light. Our results suggested that the ability of rice leaf to resist photoinhibition is related to the level of carotenoids and the ability of carotenoids biosynthesis.      

微生物诱导子对霉素PT95菌株菌核生物量和类胡萝卜素产率的影响

菌核是许多丝状真菌形成的一种休眠体。我们从土壤中分离到一株经鉴定属于Ｐｅｎｉｃｉｌｌｉｕｍｔｈｏｍｉｉｓｅｒｉｅｓ的ＰＴ95青霉菌株 ,该菌株能在固态培养基上形成大量坚硬的砂粒状的菌核 (直径约 30 0 μｍ)。ＰＴ95菌株的菌核与众不同之处在于可以积累以β 胡萝卜素为主的类胡萝卜素[1 ] 。菌核的形成 ,除了遗传因素外 ,还受多种因素影响 ,例如生长环境中的温度、水势 (Ｗａｔｅｒｐｏｔｅｎｔｉａｌ)、有机物成分等[2～ 4] 。Ｈａｗｋｅｒ[5] 认为对真菌的营养生长 (Ｖｅｇｅｔａｔｉｖｅｇｒｏｗｔｈ)有利的物质也对菌核生长有…     

Optimization of carotenoid production from hyper-producing Rhodotorula glutinis mutant 32 by a factorial approach

AIMS: Optimization of carotenoid production by a mutant of Rhodotorula glutinis. METHODS: The growth and carotenoid production was optimized in shake flasks using a two-level, three-variable factorial design. RESULTS: The volumetric carotenoid production could be increased to 129 +/- 2 mg x 1(-1) in a medium containing (g x l(-1)) yeast extract 11.74, glucose 46 and threonine 18 along with other micronutrients, wherein, beta-carotene yield was 102 +/- 2 mg x l(-1), accounting for 80% of the total carotenoids. SIGNIFICANCE AND IMPACT OF THE STUDY: The medium optimization resulted in a fourfold increase in volumetric production and a twofold increase in the cellular accumulation of carotenoids. In view of such high yields, the mutant of Rhodotorula glutinis can be a potential source of beta-carotene.     

类胡萝卜素产生菌深红酵母(Rhodotorula rubra)的培养条件的优化研究

本文研究深红酵母及其产生的类胡萝卜素的培养优化条件,并对其进行了小型发酵试验,结果表明pH值对深红酵母和类胡萝卜素有影响,初始pH值越低,色素的积累量越高,发酵过程中控制pH值能有效地增加色素积累的速度和初始色素积累量,但随着发酵时间的延长,色素积累量逐渐下降。     

Changes in Abscisic Acid During Leaf Yellowing of Cut Stock Flowers

Leaf pigments, such as chlorophyll and carotenoids, are essential plant molecules. They provide carbohydrates and energy during all plant life. Leaf pigments are also important parameters of decorative plants, such as floriculture items, cut foliage and flowers. Leaf yellowing is a form of senescence caused by an internal hormone imbalance, such as a lack of cytokinins. The aim of this study was to investigate the changes in total carotenoids and endogenous ABA in cut flower stock leaves during post-harvest life. The effect of pulse treatment with 5 or 10 M thidiazuron (TDZ), 150 mg l^–1 8-hydroxyquinoline sulphate (8-HQS) and combinations of TDZ with 8-HQS on total carotenoids and ABA concentration was also investigated. Results showed that total carotenoids drastically decreased from 1548 g cm^–2, until reaching 565 g cm_–2 at the end of vase life. Endogenous ABA strongly increased at the same time, going from 167 ng g^–1 DW at the beginning of the experiment to 1322 ng g^–1 DW at the end of vase life. The TDZ inhibited carotenoid degradation, but did not affect the ABA concentration, while the 8-HQS did not prevent carotenoid degradation and the ABA concentration was only slightly affected. ABA seems to be a secondary senescence bio-product that may have a synergic effect with other senescence inducers dramatically accelerating leaf senescence.     

Algal carotenoids 52; secondary carotenoids of algae 3; carotenoids in a natural bloom of Euglena sanguinea

Quantitative carotenoid analysis of a natural bloom of Euglena sanguinea Ehrenberg revealed the presence of β,β-carotene (1% of total carotenoids), monoesters of adonirubin (3%), diesters of (3S, 3′R)-adonixanthin (13%), diesters of (3S, 3′S)-astaxanthin (75%), 19-monoester of (3R, 3′R, 6R)-loroxanthin (1%), (3R, 3′R)-diatoxanthin (6%), diadinoxanthin (1%) and neoxanthin (traces). The carotenoid content amounted to 0.7% of the dry wt. Methods employed included TLC, HPLC, VIS, MS, CD and H NMR (400 and 500 MHz). The high content of ketocarotenoids is characteristic of secondary carotenoids produced under stressed growth conditions. Previously secondary carotenoids were associated with green algae (Chlorophyceae), but have now been encountered in Euglenophyceae.     

CAROTENOIDS PRODUCTION IN DIFFERENT CULTURE CONDITIONS BY Sporidiobolus pararoseus

Carotenoids produced by Sporidiobolus pararoseus were studied. It was found that biomass was connected with carbon source, temperature, and pH, but carotenoids proportion was seriously influenced by dissolved oxygen and nitrogen source. Different carotenoids could be obtained by using selected optimum conditions. In the end we established the strategies to produce β-carotene or torulene. Fed-batch fermentation in fermentor was used to prove the authenticity of our conclusions. The cell biomass, β-carotene content, and β-carotene proportion could reach 56.32 g/L, 18.92 mg/L and 60.43%, respectively, by using corn steep liquor at 0–5% of dissolved oxygen saturation. β-Carotene content was 271% higher than before this addition. The cell biomass, torulene content, and torulene proportion could reach 62.47 g/L, 31.74 mg/L, and 70.41%, respectively, by using yeast extract at 30–35% of dissolved oxygen saturation. Torulene content was 152% higher than before this addition. The strategy for enhancing specific carotenoid production by selected fermentation conditions may provide an alternative approach to enhance carotenoid production with other strains.     

Northern berries as a source of carotenoids

Carotenoids are bioactive substances in human diet. The aim of the study was to determine β-carotene and xanthophylls in four berries species. An HPLC gradient elution system were used for separation and quantification of the carotenoids. The highest total carotenoid content among the berries studied was found in cloudberry (2840 μg/100g dw), followed by blueberry (2140 μg/100 g). All berries had lutein but it was a predominant carotenoid in blueberry. The highest β-carotene levels were found in cloudberry (83% of total Car content). Cranberry and cowberry were the poorest sources of carotenoids. Our data will be included in the regional database of resources with the increased nutritional value.     

Photoautotrophic cultivating options of freshwater green microalgal Chlorococcum humicola for biomass and carotenoid production

Photoautotrophic cultivation of Chlorococcum humicola was performed in batch and continuous modes in different cultivating system arrangements to compare biomass and carotenoids’ concentration and their productivities. Batch result from stirred tank and airlift photobioreactors indicated the positive effect of increasing light intensity on growth and carotenoid production, whereas the finding from continuous cultivation indicated that carotenoid enhancement preferred high light intensity and nitrogen-deficient environment. The highest biomass (1.31?±?0.04?g?L^?1) and carotenoid (4.59?±?0.06?mg?L^?1) concentration as well as the highest productivities, 0.46?g?L^?1 d^?1 for biomass and 1.61?mg?L^?1 d^?1 for carotenoids, were obtained when maintaining high light intensity of 10 klx, BG-11 medium and 2% (v/v) CO₂ simultaneously, while the highest carotenoid content (4.84?mg?g^?1) was associated with high light intensity and nitrogen-deficient environment, which was induced by feed-modified BG-11 growth medium containing nitrate 20 folds lower than the original medium. Finally, the cultivating system arranged into smaller stirred tank photobioreactors in series yielded approximately 2.5 folds increase in both biomass and carotenoid productivities relative to using single airlift photobioreactor with equivalent working volume and similar operating condition.