beta-Carotene production in sugarcane molasses by a Rhodotorula glutinis mutant

Several wild strains and mutants of Rhodotorula spp. were screened for growth, carotenoid production and the proportion of -carotene produced in sugarcane molasses. A better producer, Rhodotorula glutinis mutant 32, was optimized for carotenoid production with respect to total reducing sugar (TRS) concentration and pH. In shake flasks, when molasses was used as the sole nutrient medium with 40 g l⁻¹ TRS, at pH 6, the carotenoid yield was 14 mg l⁻¹ and -carotene accounted for 70% of the total carotenoids. In a 14-l stirred tank fermenter, a 20% increase in torulene content was observed in plain molasses medium. However, by addition of yeast extract, this effect was reversed and a 31% increase in -carotene content was observed. Dissolved oxygen (DO) stat fed-batch cultivation of mutant 32 in plain molasses medium yielded 71 and 185 mg l⁻¹ total carotenoids in double- and triple-strength medium, respectively. When supplemented with yeast extract, the yields were 97 and 183 mg l⁻¹ total carotenoid with a 30% increase in -carotene and a simultaneous 40% decrease in torulene proportion. Higher cell mass was also achieved by double- and triple-strength fed-batch fermentation. Journal of Industrial Microbiology & Biotechnology (2001) 26, 327–332. Received 18 September 2000/ Accepted in revised form 02 March 2001     

Purification of an epoxide hydrolase from Rhodotorula glutinis

The epoxide hydrolase from Rhodotorula glutinis was isolated and initially characterized. The enzyme was membrane associated and could be solubilized by Triton X-100. Purification yielded an enzyme with sp. act. of 66 mol 1,2-epoxyhexane hydrolyzed min^–1 mg^–1 protein. The enzyme was not completely purified to homogeneity but, nevertheless, a major protein was isolated by SDS-PAGE for subsequential amino acid determination of peptide fragments. From sequence alignments to related enzymes, a high homology towards the active site sequences of other microsomal epoxide hydrolases was found. Molecular mass determinations indicated that the native enzyme exists as a homodimer, with a subunit molecular mass of about 45 kDa. Based upon these, this epoxide hydrolase is structurally related to other microsomal epoxide hydrolases.     

粘红酵母在味精废水中发酵生产油脂

对粘红酵母菌株进行驯化得到一株优良菌株Rh8,利用其在味精废水中发酵以去除废水中的化学需氧量(COD)并生产油脂;考察废水pH以及添加葡萄糖母液、营养因子等对菌株Rh8在味精废水中生长、产油和COD去除效果的影响,发现将废水稀释4倍、调节pH至5.5时,菌株可以较好地生长;而添加废葡萄糖母液、酵母粉、KH2PO4、MgSO4、MnSO4均能够促进菌体的生长、产油和废水中的COD去除,在250 mL摇瓶中,生物量最高可达15.6 g/L,干菌体中油脂质量分数达到29.61%,COD去除率达到45.1%。     

影响黏红酵母黏附牙鲆肠黏液的因素研究

目的研究pH、温度、二价阳离子对黏红酵母黏附作用的影响以及不同生长阶段的黏红酵母对牙鲆肠黏液的黏附特点。方法以牙鲆肠黏液作为黏附模型,采用MTT比色法测定黏红酵母在上述影响因素作用下的黏附能力。结果在10~30℃黏红酵母对牙鲆肠黏液的黏附随温度升高而增强,中性偏酸的环境有利于黏红酵母的黏附;Ca2 能显著增加黏红酵母的黏附,但Mg2 促黏附作用不明显;处于对数生长期的黏红酵母对牙鲆肠黏液的黏附能力最强,其次是延滞期的酵母,而稳定期和衰亡期的黏红酵母黏附能力显著减弱。结论黏红酵母对牙鲆肠黏液的黏附作用不仅受多种环境因子的影响,也受其自身生理状态的影响,其黏附作用具有可控性,这对黏红酵母在牙鲆肠道内黏附、定植的调控有一定的参考价值。     

耐乙酸粘红酵母合成油脂

乙酸是木质纤维素在水解过程中的主要副产物,高浓度的乙酸严重影响产油微生物的生长和油脂合成。本文研究了粘红酵母对乙酸的耐受性及其利用乙酸合成微生物油脂的能力。结果表明,在初始葡萄糖、木糖浓度分别为6 g/L和44 g/L的混合糖培养基中,乙酸浓度低于10 g/L时,不会对菌体生长产生抑制作用,油脂合成还得到了促进。当乙酸添加量为10 g/L时,生物量、油脂产量、油脂含量较对照组分别提高了21.5%、171.2%和121.6%。进一步研究表明,粘红酵母具备利用乙酸合成油脂的能力,当以乙酸为唯一碳源,浓度为25 g/L时,油脂产量达到3.20 g/L,油脂质量得率为13%。微生物油脂成分分析表明,粘红酵母以乙酸为底物制得的油脂可以作为制备生物柴油的油脂原料,其主要成分为棕榈酸、硬脂酸、油酸、亚油酸和亚麻酸,其中饱和脂肪酸和不饱和脂肪酸含量分别为40.9%和59.1%。由于粘红酵母具有利用乙酸合成微生物油脂的能力,在以木质纤维素水解液为原料生产微生物油脂的脱毒过程中,一定浓度的乙酸可以不必脱除。     

Highly enantiomeric reduction of acetophenone and its derivatives by locally isolated Rhodotorula glutinis

Ninety isolates of microorganisms belonging to different taxonomical groups (30 bacteria, 20 yeast, and 40 fungi) were previously isolated from various samples. These isolates were screened as reducing agents for acetophenone 1a to phenylethanol 2a . It was found that the isolate EBK‐10 was the most effective biocatalyst for the enantioselective bioreduction of acetophenone. This isolate was identified as Rhodotorula glutinis by the VITEK 2 Compact system. The various parameters (pH 6.5, temperature 32°C, and agitation 200 rpm) of the bioreduction reaction was optimized, which resulted in conversions up to 100% with >99% enantiomeric excesses (ee) of the S‐configuration. The preparative scale bioreduction of acetophenone 1a by R. glutinis EBK‐10 gave (S)‐1‐phenylethanol 2a in 79% yield, complete conversion, and >99% ee. In addition, R.glutinis EBK‐10 successfully reduced various substituted acetophenones. Chirality, 2010. © 2010 Wiley‐Liss, Inc.     

粘红酵母和酿酒酵母联合处理味精废水

为了解决味精废水中高NH4+浓度抑制油脂微生物的生长和油脂积累问题,采用粘红酵母和酿酒酵母联合处理味精废水的方法:首先利用酿酒酵母降解味精废水(MSG)中NH4+,然后将处理后的废水进一步发酵培养合成油脂。研究结果表明:用经酿酒酵母预处理过的味精废水作为粘红酵母的培养基发酵时,粘红酵母的生物量为33.3 g/L,油脂产率为18.16%,COD降解率为50.6%,NH4+的降解率为93.9%。比粘红酵母单独处理味精废水,NH4+的降解率提高了6.14倍,生物量、油脂产率和COD降解率分别提高了8.1%、30.06%和9.58%。     

Polyphasic taxonomy of the basidiomycetous yeast genus Rhodotorula: Rh. glutinis sensu stricto and Rh. dairenensis comb. nov

The phenotypic and genetic heterogeneity of the basidiomycetous yeast species Rhodotorula glutinis was investigated in a group of 109 isolates. A polyphasic taxonomic approach was followed which included PCR fingerprinting, determination of sexual compatibility, 26S and ITS rDNA sequence analysis, DNA-DNA reassociation experiments and reassessment of micromorphological and physiological attributes. The relationships with species of the teleomorphic genus Rhodosporidium were studied and isolates previously identified as Rh. glutinis were found to belong to Rhodosporidium babjevae, Rhodosporidium diobovatum and Rhodosporidium sphaerocarpum. Other isolates included in the study were found to belong to Rh. glutinis var. dairenensis, which is elevated to the species level, or to undescribed species. The concept of Rh. glutinis sensu stricto is proposed due to the close phenetic and phylogenetic proximity detected for Rh. glutinis, Rhodotorula graminis and R. babjevae.     

粘红酵母和钝顶螺旋藻混合培养生产微生物油脂培养基优化

通过单因素实验和正交实验对粘红酵母和钝顶螺旋藻混合培养的培养基进行了优化,得到的优化培养基于5L发酵罐中实验,葡萄糖质量浓度低于10．0g／L时,开始流加600g／L葡萄糖,控制葡萄糖质量浓度在（20±5）g/L,最终得到的油脂产量达到16．0g／L。     

糠醛对粘红酵母生长与油脂积累的影响

为了探究纤维素水解液中常见的发酵抑制物糠醛对粘红酵母Rhodotorula glutinis生长与油脂积累的影响,对比了不同的糠醛浓度(0.1、0.4、0.6、1.5 g/L)下粘红酵母的生物量和油脂积累情况,并探究了1.0 g/L的糠醛对粘红酵母不同碳源(葡萄糖和木糖)利用的影响。研究表明,当糠醛浓度达1.5 g/L时,粘红酵母的延迟期延长至96 h,残糖高达17.7 g/L,生物量最高6.6 g/L,仅为正常积累量的47%,油脂含量也减少了约50%;以木糖为碳源时,糠醛对粘红酵母的抑制程度小于葡萄糖为碳源时的情况;在糠醛存在的逆境中,粘红酵母倾向于生成更多的18碳脂肪酸或18碳不饱和脂肪酸。     

粘红酵母产L-苯丙氨酸解氨酶发酵培养基的优化

通过单因子和正交试验 ,对粘红酵母产 L -苯丙氨酸解氨酶 ( PAL )培养基进行优化 ,L-苯丙氨酸的积累浓度可以从 2 .0 g/1 0 0 ml提高到 3 .3 g/1 0 0 ml,最终得到了 L-苯丙氨酸解氨酶发酵的最适条件     

Effect of ammonium-N on malic enzyme and lipid production in Rhodotorula glutinis grown on monosodium glutamate wastewater

Rhodotorula glutinis, an oil producing strain, can utilize monosodium glutamate (MSG) wastewater as a raw material for lipid production. The effects of ammonium-N in the MSG wastewater (ammonium 15,000–25,000?mg/L, COD 30,000–50,000?mg/L) on cell growth, lipid accumulation and malic enzyme activity of R. glutinis have been studied. Four initial ammonium sulfate concentrations in the medium were set, which were 20, 60, 100, and 140?g/L. With an increase in the ammonium sulfate concentration, the uptake of ammonia nitrogen and lipid accumulation increased while the biomass decreased at 72?h. The maximum value of ammonia nitrogen consumption reached 5.77?g/L for an initial ammonium sulfate concentration of 140?g/L at 72?h. In addition, 60?g/L ammonium sulfate concentration may be an appropriate concentration for R. glutinis cultivation. The activity of the malic enzyme was measured and the results showed that there was a linear relationship between the intracellular lipid content and the total malic enzyme activity.     

Manipulation of temperature and illumination conditions for enhanced beta-carotene production by mutant 32 of Rhodotorula glutinis

AIMS: Enhancement in the production of beta-carotene by the hyper producer mutant 32 of Rhodotorula glutinis by manipulation of temperature and illumination. METHODS AND RESULTS: Growth and beta-carotene production was investigated in a 1 litre fermenter at different temperature and illumination conditions. The optimum temperature for growth and beta-carotene production was 30 and 20 degrees C, respectively. At 30 degrees C, beta-carotene production was 125 +/- 2 mg l-1 and accounted for 66% of the total carotenoids in 72 h; at 20 degrees C, it was 250 +/- 7 mg l-1 and accounted for 92% of total carotenoid content. Continuous illumination of the fermenter by 1000 lx white light hampered growth as well as carotenoid synthesis. At 30 degrees C, illuminating the fermenter in late logarithmic phase resulted in a 58% increase in beta-carotene production with a concurrent decrease in torulene; at 20 degrees C, however, it showed no appreciable increase. SIGNIFICANCE AND IMPACT OF THE STUDY: Proper manipulation of culture conditions enhanced beta-carotene production by R. glutinis which makes it a significant source of beta-carotene.     

Caroteno-protein and exopolysaccharide production by co-cultures of Rhodotorula glutinis and Lactobacillus helveticus

The lactose-negative yeast Rhodotorula glutinis 22P and the homofermentative lactic acid bacterium Lactobacillus helveticus 12A were cultured together in a cheese whey ultrafiltrate containing 42 g L⁻¹ lactose. The chemical composition of the caroteno-protein has been determined. The carotenoid and protein contents are 248  μ g g⁻¹ dry cells and 48.2% dry weight. Carotenoids produced by Rhodotorula glutinis 22P have been identified as β-carotene 15%, torulene 10%, and torularhodin 69%. After separating the cell mass from the microbial association, the exopolysaccharides synthesized by Rhodotorula glutinis 22P were isolated from the supernatant medium in a yield of 9.2 g L⁻¹. The monosaccharide composition of the synthesized biopolymer was predominantly D-mannose (57.5%). Received 08 July 1996/ Accepted in revised form 11 December 1996     

An optimization study of carotenoid production by Rhodotorula glutinis DBVPG 3853 from substrates containing concentrated rectified grape must as the sole carbohydrate source

A multivariate statistical approach was employed for the optimization of conditions for carotenoid production by Rhodotorula glutinis DBVPG 3853 from a substrate containing concentrated rectified grape must as the sole carbohydrate source. Several experimental parameters (carbohydrate, yeast autolysate and salt concentrations, and pH) were tested at two levels by following a fractional factorial design. Carotenogenesis was most sensitive to both initial pH and yeast autolysate concentration. A Central Composite Design experiment was then performed by obtaining both second-order polynomial models and isoresponse diagrams where initial pH and yeast autolysate concentration were considered as variables. In this way it was possible to determine the conditions (pH = 5.78, yeast autolysate = 4.67 g L⁻¹) which maximize both the concentration of total carotenoids and that of β-carotene (6.9 mg L⁻¹ and 1100 μg L⁻¹ of culture fluid, respectively, after 120 h of fermentation). Journal of Industrial Microbiology & Biotechnology (2000) 24, 41–45. Received 23 February 1999/ Accepted in revised form 14 September 1999     

Studies on lipid production by Rhodotorula glutinis fermentation using monosodium glutamate wastewater as culture medium

Microbial lipid, as a raw material for biodiesel, can be produced by Rhodotorula glutinis with the monosodium glutamate (MSG) wastewater. The effect of adding glucose to MSG wastewater on lipid production was studied in this paper. Three different strategies, including initial addition, fed-batch addition and glucose feedback addition were attempted. The results show that addition of glucose was found favorable not only for cell growth but also for lipid synthesis. Of the three adding methods glucose feedback addition was the most effective one: about 25 g/L of biomass, 20% of lipid content and 45% of COD degradation were obtained respectively. And the components of the resulted lipid using different addition strategies were further studied.     

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.     

Optimization of pineapple pulp residue hydrolysis for lipid production by Rhodotorula glutinis TISTR5159 using as biodiesel feedstock

The higher lipid productivity of Rhodotorula glutinis TISTR5159 was achieved by optimizing the pineapple pulp hydrolysis for releasing the high sugars content. The sequential simplex method operated by varied; solid-to-liquid ratio, sulfuric acid concentration, temperature, and hydrolysis time were successfully applied and the highest sugar content (83.2 g/L) evaluated at a solid-to-liquid ratio of 1:10.8, 3.2% sulfuric acid, 105 °C for 13.9 min. Moreover, the (NH₄)₂SO₄ supplement enhanced the lipid productivity and gave the maximum yields of biomass and lipid of 15.2 g/L and 9.15 g/L (60.2%), respectively. The C16 and C18 fatty acids were found as main components included oleic acid (55.8%), palmitic acid (16.6%), linoleic acid (11.9%), and stearic acid (7.8%). These results present the possibility to convert the sugars in pineapple pulp hydrolysate to lipids. The fatty acid profile was also similar to vegetable oils. Thus, it could be used as potential feedstock for biodiesel production.     

粘红酵母乙酰辅酶A羧化酶（ACC）基因的克隆及CT功能域基因的原核表达

利用简并PCR结合染色体步移法首次克隆获得粘红酵母乙酰辅酶A羧化酶（ACC）基因的全长序列信息。序列分析表明,该基因包含2个内含子,分别位于42～147 bp和315～677 bp处,编码区域总长为6 801bp,推导的氨基酸序列进行二级结构分析具备乙酰辅酶A羧化酶典型的3个功能域：生物素羧化酶（BC）、生物素羧基载体蛋白（BCCP）和羧基转移酶（CT）。克隆该基因的CT功能域基因,连接到原核表达载体pET-28a上,在Escherichia coli BL21（DE3）中成功表达,利用Ni-NTA树脂柱纯化获得CT的可溶性重组蛋白,浓度为1.8mg/mL,为研究ACC的功能和针对CT作用的除草剂机理研究提供了有价值的材料。     

Transport und Umsatz von Polyalkoholen bei der Hefe Rhodotorula gracilis (glutinis)

Zusammenfassung Die Polyalkohole Sorbitol, d-Mannitol, Ribitol, Xylitol, d-Arabitol, l-Arabitol und Erythritol werden von der obligat aeroben Hefe Rhodotorula gracilis über einen beweglichen Träger in der Zellmembran aufgenommen. Der Transportmechanismus ist aktiv, das erreichte Akkumulationsverhältnis ist jedoch bei allen Polyalkoholen erheblich geringer als bei Monosacchariden. Es nimmt, wie auch bei Monosacchariden, mit steigender Außenkonzentration ab, sogar auf Werte kleiner als 1.Kinetische Daten weisen darauf hin, daß das Trägersystem für Polyalkohole identisch ist mit dem für Monosaccharide, jedoch für Polyalkohole eine wesentlich geringere Affinität und maximale Geschwindigkeit aufweist. Aufgrund des hohen Affinitätsunterschiedes wird die Polyalkoholaufnahme in der Anwesenheit von Monosacchariden unterbunden.Die aufgenommenen Polyalkohole werden im Zellinneren nicht umgesetzt; eine Ausnahme stellen Ribitol und l-Arabitol dar, in deren Anwesenheit ein Abbausystem für Pentitole induziert wird.

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Transport and utilization of alditols in the yeast Rhodotorula gracilis (glutinis) I. Constitutive transport of alditols

The obligate aerobic yeast Rhodotorula gracilis was found to take up the alditols d-glucitol, d-mannitol, ribitol, xylitol, d-arabinitol, l-arabinitol and erythritol by means of a constitutive mobile membrane carrier. This uptake involved active transport, that is, it was dependent on the supply of metabolic energy, leading to the accumulation of alditols inside the cells. The accumulation ratio (intracellular concentration to extracellular concentration, S _i /S _o ) was much lower for alditols than for monosaccharides. As for monosaccharides, this ratio decreased with increasing extracellular concentration, even to values below 1.The kinetic data showed that the carrier system for alditols was identical to that for monosaccharides, though it had a much lower affinity and maximum velocity for alditols. Hence the uptake of alditols was blocked in the presence of monosaccharides.Only ribitol and l-arabinitol were catabolized following enzyme induction. The other alditols were not broken down.