一株法夫酵母虾青素高产菌株的生产性能

为了评价虾青素高产菌株-法夫酵母JMU-MVP14的生产性能及建立虾青素高产发酵技术,通过测定糖、生物量、虾青素产量、总类胡萝卜素产量等发酵参数,用摇瓶试验对比了法夫酵母JMU-MVP14和出发菌株的差异,用7 L罐试验对比了pH值调控方式及补料培养基成分对发酵的影响,用1 m3罐试验评估了法夫酵母JMU-MVP14高密度发酵虾青素的产量水平。摇瓶发酵结果表明,法夫酵母JMU-MVP14虾青素及总类胡萝卜素的细胞产率分别达到6.01 mg/g及10.38 mg/g;7 L罐分批发酵试验结果表明,自动流加调     

法夫酵母生物合成虾青素的研究

本文对法夫酵母是青素的生命合成进行了研究。实验结果表明,法夫酵母在ＹＥＰＤ培养基中生长时表现出二次生出现象,细胞内虾青素的合成是与细胞季开偶联的,在约６６ｈ达一在积累,３．４μｇ／ｍｌ。     

基于动力学模型的法夫酵母发酵生产虾青素的补料策略优化

对法夫酵母的不同补料发酵方式进行了研究.基于底物抑制模型,提出了一种优化的两阶段补料策略,用于法夫酵母产虾青素的高密度发酵.在发酵的延迟期和对数生长期早期,糖浓度控制在25 g/L左右,在此条件下,生物量可以达到最大,且时间缩短.在对数生长期后期及稳定期,糖浓度控制在5 g/L,虾青素的合成时间可以有效延长.与传统的补料方式相比,采用此补料策略取得了较好的发酵效果.发酵终点细胞干重达到23.8g/L,虾青素产量达到29.05 mg/L,分别比分批发酵提高了52.8%和109%.     

法夫酵母生产虾青素发酵条件的研究

方法：分别进行了接种时间、摇床转速、接种量和装液量对法夫酵母细胞生产虾青素摇瓶发酵过程影响的实验,比较了DMSO法、酸热法、碱法和自溶法等破壁方法和提取溶剂之间的差别,测定了法夫酵母生长过程中的生物量、类胡萝卜素产量和培养基中的残糖。结果：确定了最佳的摇瓶发酵条件为：种瓶至发酵摇瓶的接种时间为40h,摇床转速为160r/min,接种量为10%,装液量为50mL;DMSO法和丙酮分别为合适的破壁方法和提取溶剂。结论：初步确定发酵的基本条件,为进行法夫酵母高产虾青素菌种的筛选以及发酵培养基的优化奠定了基础。     

法夫酵母产虾青素的反复分批及反复分批补料发酵

以生物量和虾青素产量为指标,考察法夫酵母多批次半连续培养产虾青素的稳定性。实验结果显示,在摇瓶上分别以4 d和5 d为周期反复分批培养法夫酵母,虾青素产量呈现先增加再下降的趋势,但第2代至第7代虾青素产量仍高于第1代,并且4 d为周期的虾青素平均产量略高于5 d的。在5 L罐法夫酵母进行反复分批补料发酵中,不管是补加30％的葡萄糖还是补加30％的淀粉水解糖,第2个批次发酵的生物量和虾青素产量均达到第1个批次的水平,表明菌种稳定性较好。     

法夫红酵母高产虾青素菌株的研究概况

虾青素是一种天然类胡萝卜素,具有较强的抗氧化作用。法夫红酵母是一种能合成虾青素的真菌。本文主要概述法夫红酵母高产虾青素菌株的育种、高产株选择、培养条件和虾青素的提取检测方法     

法夫红酵母主同产虾青素菌株的研究概况

虾青素是一种天然类胡萝卜素,具有较强的抗氧化作用。法夫红酵母是一种能合成虾青素的真菌。本文主要概述法夫红酵母高产虾青素菌株的育种、高产株选择、培养条件和虾青素的提取检测方法。     

高产虾青素红发夫酵母选育研究进展

虾青素是 60 0多种类胡萝卜素中的一种 ,具有抗氧化 ,抗肿癌和增强免疫力等许多重要的生理和生物学功能 ,在水产养殖、食品和医药等领域应用前景广阔。综述了虾青素的生物来源、生物转化途径以及高产虾青素红发夫酵母菌株的选育。     

Growth kinetics and astaxanthin production of Phaffia rhodozyma on glycerol as a carbon source during batch fermentation

Glycerol was studied as a substrate for astaxanthin by Phaffia rhodozyma PR 190. With co-utilisation of yeast extract and peptone, the maximum specific growth rate was 0.24 ± 0.02 h–1. Astaxanthin percentage in total pigment is constant (0.78 mg/g) and its yield from glycerol is always 0.97 mg/g. The yield of biomass from glycerol alone is 0.50 ± 0.02 g/g. The specific rate of astaxanthin production versus the cell growth rate reached a maximum for an optimal specific growth rate of 0.075 h–1. For this optimal value, the maximum specific astaxanthin production rate is 0.09 ± 0.01 mg/g.h. The best astaxanthin results were : 33.7 mg/l, 0.2 mg/l.h and 1.8 mg/g yeast after a fermentation term of 168 hours. Our results suggest a strategy of astaxanthin production in fed batch culture or chemostat at a growth rate of 0.075 h–1. © Rapid Science Ltd. 1998     

虾青素摇瓶发酵条件的研究

通过对P .rhodozyma 4 - 2 6的虾青素摇瓶发酵条件包括接种比、通气量和温度等 ,以及培养基主要组分的优化 ,得到最优培养基及培养条件。在此条件下发酵 72h ,虾青素量可达 13 4 5μg/ml或 146 5μg/gCDW ,较优化前提高 1 4 8倍。     

虾青素高产菌的选育

红发夫酵母（Phaffia rhodozyma)是微生物发酵法生产虾青素的优良菌株,作者采用Cs^137-γ射线重复辐照,并进行亚硝基胍（NTG）诱变处理,选育得到一株高产虾青素的红发夫酵母YB-20-28突变株,该菌株摇瓶发酵的生物量达老人家酵母YB-20-28突变株,该菌株摇瓶发酵的生物量达36.3g/L,总色素含量为1216.0μg/g,较出发菌株提高308%,虾青素产量达30.9μg/mL,是一株颇具开发潜力的虾青素高产菌株。     

响应面法对红法夫酵母合成虾青素主要影响因素的优化

在单因素试验确定了红法夫酵母生物合成虾青素培养基组份的基础上,用响应面法对其浓度进行优化。首先用分式析因设计评价了培养基的各组份对虾青素产量的影响,并找出主要影响因子为蔗糖和酵母粉,二者分别达到了极显著和显著水平。用最陡爬坡路径逼近最大响应区域后,运用旋转中心复合设计及响应面分析,确定了主要影响因子的最佳浓度。其中,蔗糖的最佳浓度为49.8g/L,酵母粉的浓度为9.6g/L。菌株在优化培养基中的虾青素产量为9861μg/L,比优化前增加了近1倍。     

Batch cultivation and astaxanthin production by a mutant of the red yeast,Phaffia rhodozyma NCHU-FS501

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.     

Increased astaxanthin production by a Phaffia rhodozyma mutant grown on date juice from Yucca fillifera

The wild strain and the astaxanthin-overproducing mutant strain 25–2 of Phaffia rhodozyma were analyzed in order to assess their ability to grow and synthesize astaxanthin in a minimal medium composed of g L⁻¹: KH₂PO₄ 2.0; MgSO₄ 0.5; CaCl₂ 0.1; urea 1.0 and supplemented with date juice of Yucca fillifera as a carbon source (yuca medium). The highest astaxanthin production (6170 μg L⁻¹) was obtained at 22.5 g L⁻¹ of reducing sugars. The addition of yeast extract to the yuca medium at concentrations of 0.5–3.0 g L⁻¹ inhibited astaxanthin synthesis. The yuca medium supported a higher production of astaxanthin, 2.5-fold more than that observed in the YM medium. Journal of Industrial Microbiology & Biotechnology (2000) 24, 187–190. Received 14 July 1999/ Accepted in revised form 02 December 1999     

Genetics and electrophoretic karyotyping of wild-type and astaxanthin mutant strains of Phaffia rhodozyma

In this work we establish the chromosomal composition of a wild-type, one astaxanthin and two -carotene overproducer strains of the red yeast Phaffia rhodozyma. The method used has been pulsed field gel electrophoresis, which has determined 9 DNA chromosomal bands in the yeast genome. The two largest bands are triplets and two other bands, VI and VIII, seem to be doublets. The size of the chromosomal bands varies between 0.35 and 2.5 Mb, suggesting a genome size of 25 Mb. The technique used, complemented with hybridization assays using specific DNA probes, provides direct information about the genomic organization of P. rhodozyma. We have also cloned and located in chromosomal bands different DNA sequences that code for the translation elongation factor 1 alpha (ef-1), a 7.6 kb BamHI fragment of repetitive DNA (possibly rDNA) and a randomly chosen fragment (named locus R2). Additionally, we have detected a chromosomal length polymorphism between wild-type strains and mutant strains affecting carotenogenesis obtained in our laboratory.     

L-异亮氨酸分批发酵动力学模型的研究

对黄色短杆菌L－异亮氨酸高产菌XQ－4（AHV^rAEC^rSuc^gSG^rEth^rα－AB^rIleHx^r）分批发酵动力学模型进行了研究。建立了比较合理的L－异亮氨酸分批发酵动力学模型,为L－异亮氨酸补料分批发酵最优化的研究奠定基础。     

不同补料发酵方式对发夫酵母产虾青素的影响

对发夫酵母的不同补料发酵方式进行了研究,期望提高发酵产率,以便对工业化生产提供一定的指导作用。实验结果表明：采用恒pH葡萄糖-氨水流加培养,色素量和生物量均具有最大值,分别为54.3μg/ml和49.5μg/ml;其次是指数流加培养,色素量和生物量分别为49.9μg/ml和47.4mg/ml;恒pO2流加方式下色素量和生物量分别为34.04ug/ml和35.4mg/ml;恒pH葡萄糖流加方式所得的色素量和生物量最小,分别为32.3μg/ml和31.5mg/ml。不同的补料发酵方式对发夫酵母生长和色素形成的影响很大。     

Improvement of astaxanthin production by a newly isolated Phaffia rhodozyma mutant with low-energy ion beam implantation

Aims: Isolation, characterization and identification of Phaffia sp. ZJB 00010, and improvement of astaxanthin production with low‐energy ion beam implantation. Methods and Results: A strain of ZJB 00010, capable of producing astaxanthin, was isolated and identified as Phaffia rhodozyma, based on its physiological and biochemical characteristics as well as its internal transcribed spacer (ITS) rDNA gene sequence analysis. With low‐energy ion beam implantation, this wild‐type strain was bred for improving the yield of astaxanthin. After ion beam implantation, the best mutant, E5042, was obtained. The production of astaxanthin in E5042 was 2512 μg g^?1 (dry cell weight, DCW), while the wild‐type strain was about 1114 μg g^?1 (DCW), an increase of 125·5%. Moreover, the fermentation conditions of mutant E5042 for producing astaxanthin were optimized. The astaxanthin production under the optimized conditions was upscaled and studied in a 50‐l fermentor. Conclusions: A genetically stable mutant strain with high yield of astaxanthin was obtained using low‐energy ion beam implantation. This mutant may be a suitable candidate for the industrial‐scale production of astaxanthin. Significance and Impact of the Study: Astaxanthin production in Phaffia rhodozyma could be fficiently improved by low‐energy ion beam implantation, which is a new technology in the mutant breeding of micro‐organisms. The mutant obtained in this work could potentially be utilized in industrial production of astaxanthin.