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Summary As Phaffia rhodozyma is a Crabtree positive yeast, its cell yield and pigment production are reduced at high sugar concentrations. A method for maintaining low growth medium sugar concentrations is fed-batch culture. Using a mass balance approach and Monod growth kinetics a model is presented which describes the fed-batch culture of Phaffia rhodozyma and enables the calculation of a feed regime to obtain the maximum yield of cells and pigment. Although developed on a glucose medium, the model was also applied successfully to a molasses-based medium. 相似文献
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On-line monitoring of Phaffia rhodozyma fed-batch process with in situ dispersive Raman spectroscopy
Since the yeast Phaffia rhodozyma was first described some 35 years ago, there has been significant interest in the development of commercial processes to exploit its ability to produce carotenoids (approximately 80% astaxanthin). However, the optimal conditions for carotenoid production are not well understood. A key limitation has been the lack of an appropriate sensor for on-line carotenoid quantification. In this study, an in situ Raman spectroscopy probe was used to monitor intracellular carotenoid production for three consecutive P. rhodozyma fed-batch experiments. Raman spectroscopy is particularly well suited to the study of carotenoids due to a resonance effect, which greatly enhances the intensity of the three fundamental carotenoid bands, nu(1) (1513 cm(-1), C(-) (-)C stretch), nu(2) (1154 cm(-1), C-C stretch), and nu(3) (1003 cm(-1), CH(3) rock). For all three cultures, the peak height of these bands was linearly correlated with intracellular carotenoid content (1 to 45 mg/L) to a precision of better than 5%, and the correlation from one experiment was directly applicable to others. 相似文献
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Response surface methodology was applied to optimize the growth of the yeast Phaffia rhodozyma in continuous fermentation using peat hydrolysates as substrate. A second-order, complete, factorial design of the experiments was used to develop empirical models providing a quantitative interpretation of the relationships between the two variables studied, dilution rate and pH. Maximum biomass concentration in the fermentor was obtained by employing the following predicted optimum fermentation conditions: a dilution rate of 0.017/h and a pH level of 7.19. A verification experiment, conducted at previously optimized conditions for maximum biomass volumetric productivity (a dilution rate of 0.022/h, and a pH level of 6.90), produced values for biomass concentration, residual substrate concentration, biomass yield, and biomass volumetric productivity that were very close to the predicted values, indicating the reliability of the empirical model. The concentration of the pigment astaxanthin produced by the yeast under the optimized growth conditions was found to be 544 mg astaxanthin/kg dry cell biomass. 相似文献
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Jerusalem artichoke extract or powder was used for astaxanthin production using Phaffia rhodozyma without acidic or enzymatic inulin hydrolysis. The culture medium containing Jerusalem artichoke as carbon source was optimized, and feeding strategies, including constant, exponential, pH-stat, and substrate feedback fed-batch fermentations, were also compared for enhancing the cell biomass and astaxanthin synthesis by P. rhodozyma. Substrate-feedback fed-batch fermentation resulted in the highest dry cell weight of 83.60 g/L, with a carotenoid concentration and yield of 982.50 mg/L and 13.30 mg/g, respectively, under optimized medium components using Jerusalem artichoke extract as carbon source in a 3-L stirred-tank bioreactor. Moreover, 482.50 mg/L of carotenoids and 253.10 mg/L of astaxanthin were obtained by continuous feeding of Jerusalem artichoke powder, which was used as carbon source. Astaxanthin essence with high DPPH-scavenging activity was obtained from the extracted astaxanthin, and the DPPH free radical scavenging rate of 40 ppm astaxanthin essence reached 76.29%. When stored at 4 °C, astaxanthin essence showed the highest stability, with a minimum k value of 0.0099 week−1 and maximum half-life (t1/2) value of 70 weeks. 相似文献
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【目的】考察不同补料工艺对法夫酵母菌株生长和虾青素合成的影响。【方法】对法夫酵母JMU-VDL668和JMU-MVP14菌株在7 L罐中进行分批及分批补料培养; 同时, 测定发酵过程中生物量、虾青素和葡萄糖含量的变化。【结果】采用恒DO补料, 法夫酵母JMU-VDL668菌株获得的生物量最大(64.6 g/L), 是分批培养的2.2倍; 采用恒pH补料发酵, 虾青素的产量最高(20.6 mg/L), 是分批培养的1.5倍。与JMU-VDL668菌株不同, 虾青素高产菌株JMU-MVP14菌株采用恒pH补料, 获得生物量最大(48.5 g/L), 但虾青素产量大大降低(仅17.5 mg/L); 采用脉冲补料, 虾青素产量最高, 达到414.1 mg/L, 与分批发酵相比提高了200.2%; 采用恒DO补料, 生物量(38.5 g/L)和虾青素产量(403.2?mg/L)增加显著, 与分批发酵相比分别提高了133.1%和192.3%。【结论】不同补料工艺对法夫酵母菌株生产虾青素影响很大。其中, 采用恒pH补料工艺, 法夫酵母JMU-VDL668菌株可以获得最高的虾青素产量, 而采用脉冲补料工艺, 最适于法夫酵母JMU-MVP14菌株发酵生产虾青素。 相似文献
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红发夫酵母的生物学特性 总被引:2,自引:0,他引:2
红发夫酵母以单细胞为主,有时能形成假菌丝。菌落因菌体产生虾青素等类胡萝卜素而呈红色,类胡萝卜素均匀地分布于细胞脂质中。红发夫酵母为专性好氧菌,细胞产生类胡萝卜素需要大量氧气。葡萄糖和蔗糖为最佳碳源,酵母膏是最佳氮源。红发夫酵母具克拉布特里效应(Crabtree)。红发夫酵母生长温度范围为4-27℃,属于兼性嗜冷的低温型微生物。最适生长pH为6.0,色素形成的最适pH为5.0。 相似文献
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L. Rubinstein A. Altamirano L. Ducrey Santopietro M. Baigorí L. C. de Figueroa 《Biotechnology Techniques》1996,10(12):929-932
Summary The transformation of Phaffia rhodozyma by electroporation was better than the one by the lithium chloride (LiCl) or spheroplast transformation methods. The influence of several parameters on transformation efficiency was studied. Electroporation conditions of 1200 Volts, 50 Farads and 2000 Ohms were proved successful. A maximum of 1.5 × 103 transformants per 100 ng of DNA was reached. 相似文献
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Ágnes Nagy Nándor Garamszegi Csaba Vágvölgyi Lajos Ferenczy 《FEMS microbiology letters》1994,123(3):315-318
Abstract Electrophoretic karyotypes of strains from the astaxanthin-producing yeast Phaffia rhodozyma have been established. Intact chromosomal DNA molecules released from protoplasts were separated by orthogonal field alternation gel electrophoresis (OFAGE) and contour clamped homogeneous electric field (CHEF). Both small and large chromosomal DNA molecules were resolved simultaneously by optimizing the running conditions. Electrophoretic karyotypes among the Phaffia isolates examined differed significantly. Seven to thirteen chromosomal bands, ranging in size from 0.83 Mb to 3.50 Mb, were resolved, giving total genome sizes of about 15.4 to 23.2 Mb. Ribosomal DNA has been assigned to chromosomal bands using a heterologous gene probe. 相似文献
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Summary This paper describes the genetic transformation of the astaxanthin-producing yeast Phaffia rhodozyma with the cloning vector pGH-1. The plasmid replicates autonomously in this yeast, and the selection of transformants was possible by using both, the URA3 marker from Saccharomyces cerevisiae, and the kanamycin resistance (KmR) determinant from the bacterial transposon Tn903. 相似文献
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Xiao-Ying Bie 《Biocatalysis and Biotransformation》2016,34(3):89-98
The effects of important production variables on the biotransformation of sucrose by immobilized cells of Phaffia rhodozyma were investigated. Cell concentration had negative effect on the maximum concentration of neokestose and the optimal concentration was 16?g/l (calculated by dry weight). The concentration of sucrose had a positive effect on the maximum concentration of neokestose within 1.170?mol/l. Elevating the reaction temperature increased the reaction rate but decreased the maximum concentration of neokestose. Sugar cane juice could be used as an inexpensive substrate for neokestose production. Additionally, a 30-d continuous neokestose production was found feasible in a packed bed reactor, indicating that the cell immobilization with chitosan-coated alginate has the potential for industrial production. 相似文献
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红色酵母原生质体形成和再生条件的研究 总被引:4,自引:0,他引:4
了不同渗透压稳定剂、酶浓度、酶解时间,温度等对红色酵母原生质体的形成与再生的影响。实验结果表明:使用对数生长期早期的细胞,蜗牛酶浓度1%,30℃处理50-6min,山梨醇为渗透压稳定剂,有利于原生质体制备和再生。 相似文献
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Addition of ethanol (0.2%) to cultures of the yeast Phaffia rhodozyma increased the specific rate of carotenoid production [(carotenoid)(cell mass)−1(time)−1]. The incremental increase in carotenoid synthesis with ethanol was highest in carotenoid-hyperproducing strains. Ethanol
increased carotenoid production when it was added at various points during the lag and active growth phases. Ethanol increased
alcohol dehydrogenase and hydroxy-methyl-glutaryl-CoA (HMG-CoA) reductase activities. Our results indicate that increased
carotenoid production by ethanol is associated with induction of HMG-CoA reductase and possibly activation of oxidative metabolism.
Received 24 December 1996/ Accepted in revised form 27 May 1997 相似文献
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Phaffia rhodozyma cells were treated with the mutagenic agent NTG several times and plated on yeast-malt agar containing -ionone as a selective medium. This mutagenesis of the yeast yielded a mutant (NCHU-FS501) with a total carotenoid content of 1454 g g–1 dry biomass. Temperature and pH had only a slight effect on the volumetric pigment production by the red yeast, however astaxanthin yield and specific growth rate were influenced more significantly by temperature and pH. The optimum inoculum size, temperature and air flow rate for astaxanthin formation by the mutant in a bench-top fermentor were 7.5% (v/v), 22.5°C and 3.6 vvm, respectively. Glucose (1%, w/v) as carbon source yielded the highest volumetric astaxanthin production (6.72 g ml–1). Peptone (15.8% total nitrogen) was the best nitrogen source for astaxanthin production (6.72 g ml–1). Pigment formation by the mutant was further improved by increasing the glucose concentration to 3.5%, where the astaxanthin concentration was 16.33 m ml–1. At 4.5% glucose or above astaxanthin formation was inhibited. Control of the pH of the fermentation broth did not improved pigment production. 相似文献
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We isolated mutants of Phaffia rhodozyma strain NRRL Y-17269 that overproduced astaxanthin when grown on corn-based fuel ethanol stillage (thin stillage, TS, or fuel ethanol byproducts). Ten ml cultures of mutant strain JB2 produced 1.54 ± 0.21 mg carotenoid/mg dry weight when grown on 70% thin stillage at pH 5.2, compared with 0.38 ± 0.04 g/mg produced by the parental strain. Furthermore, JB2 produced similar astaxanthin concentrations when grown in either thin stillage or yeast malt broth. By comparison, previously described astaxanthin overproducing strain NRRL Y-17811 yielded 1.08 ± 0.07 g/mg in yeast malt broth but only 0.67 ± 0.03 g/mg in thin stillage. Five liter fermentation experiments using JB2 grown on 70% thin stillage at pH 5.2 yielded 2.01 ± 0.17 g/mg astaxanthin. Thus, JB2 is uniquely suited for astaxanthin production from low cost thin stillage. 相似文献
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Extraction and quantitation of astaxanthin from Phaffia rhodozyma 总被引:32,自引:0,他引:32
Summary The rapid, quantitative release of astaxanthin and other carotenoids from the yeast Phaffia
rhodozyma is described. Hashed cells are ruptured with dimethylsulfoxide (DMSO) and carotenoids extracted into an organic solvent. Extraction and spectrophotometric quantitation of total carotenoids is rapid, reproducible and only small volumes (0.1–2 ml) of culture are required. HPLC analysis in normal phase silica gel column indicates that astaxanthin comprises 65–95% of the total pigmented carotenoids of P.
rhodozyma. 相似文献
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结合薄层色谱、柱色谱、以及高效液相色谱对虾青素高产菌株-法夫酵母JMU-MVP14中的类胡萝卜素成分进行初步研究。研究结果表明,硅胶柱层析和氧化镁柱层析相结合的方法对法夫酵母JMU-MVP14菌体中的类胡萝卜素成分有很好的分离效果。经过柱层析分离纯化后,各组分中类胡萝卜素的种类单一,有利于进一步通过各种波谱技术对其进行定性。此方法弥补了单纯依靠高效液相色谱(ODS 柱)对法夫酵母 JMU-MVP14菌体中类胡萝卜素分离效果不佳,可供选择的商业化类胡萝卜素标准品少,液相保留时间漂移等因素给法夫酵母JMU-MVP14菌体中类胡萝卜素定性带来的不足。 相似文献