红酵母类胡萝卜素形成的生理学研究

从数株红酵母中选出 1株产类胡萝卜素能力较强的红酵母RY 98(生物量、类胡萝卜素含量和产量分别为19.9g/L ,334 .8μg/ g和 6 .7mg/L) ;研究了该菌株产类胡萝卜素的最适营养与环境条件 ,获得了最佳的发酵生理学条件 :葡萄糖 40 g/L ,(NH4 ) 2 SO4 10 g/L ,酵母膏 3g/L ,蕃茄汁 2mL/L ,花生油 0 .5mL/L ,接种量 30mL/L ,初始pH 6 .0和通气量 (培养基装量 ) 4 0mL/ 2 5 0mL。在此初步优化的培养条件下 ,红酵母RY 98经 72h摇瓶发酵其生物量、类胡萝卜素含量和产量分别可达 2 6 .8g/L ,386 .9μg/ g和 10 .4mg/L ,依次比初筛中提高了 34 .7% ,15 .6 %和 5 5 .2 %。     

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.     

Effect of pH on lipid accumulation by an oleaginous yeast:Rhodotorula glutinis IIP-30

Maximum lipid production (66% w/w dry wt) inRhodotorula glutinis IIP-30 utilizing glucose in a fed-batch fermentation under N-limiting conditions at 30°C, was at pH 4. At pH 3, 5 and 6, the lipid contents were 12%, 48% and 44%, respectively. There was only a small change in the fatty acid profile over the pH range examined, although the ergosterol content decreased by a third as the pH increased.     

Identity and biodegradative abilities of yeasts isolated from plants growing in an arid climate

Plants harvested in the Canary Islands Lanzarote and Fuerteventura were analyzed for the yeasts inhabiting their surface. Half of the isolates (22 out of 44) were identified as Debaryomyces hansenii. Black ascomycetes, viz. Hortaea werneckii and two Hormonema species were represented by 7 strains. Basidiomycetous yeasts, viz. Cryptococcus sp. (8 strains), Rhodotorula sp. (5 strains), Cerinosterus cyanescens (1 strain) and Pseudozyma sp. (1 strain) constituted a minority of 33%. Thirty strains were screened for their ability to assimilate various plant constituents including lipids of the cuticle and the cell membrane, hemicelluloses, nitrogenous compounds (protein, nucleic acids, amino acids) and benzene compounds. All strains were able to assimilate or to hydrolyze lipids, lecithin included. Many strains of D. hansenii, H. dematioides, H. werneckii, C. cyanescens, Cr. laurentii, Pseudozyma sp. and Rh. glutinis were proteolytic. Hemicelluloses like xylan and pectin were assimilated by black ascomycetous yeasts, Cryptococcus sp., Pseudozyma sp. and Rh. glutinis. Ferulic and hydroxycinnamic acids, gallic and tannic acids were assimilated by some strains of H. dematioides, C. cyanescens, Pseudozyma sp. and Rhodotorula sp.     

Elicitor induction of furanocoumarin biosynthetic pathway in cell cultures ofRuta graveolens

Treatment with an autoclaved culture homogenate of the yeastRhodotorula rubra induces rapid accumulation of acridone epoxides, furoquinolines and furanocoumarins in cell cultures ofRuta graveolens (L). The increased accumulation is preceeded by an induction of enzymes of the biosynthetic pathways. In the case of furanocoumarins induction was shown for phenylalanine ammonia-lyase (PAL), 4-coumarate: CoA ligase (4-CL) and S-adenosyl-l-methionine: xanthotoxol O-methyltransferase (XOMT). For PAL and 4-CL time courses of induced activity showed an early maximum, 8–12 h after treatment, whereas XOMT was found to reach its maximum later, about 36–42 h after treatment. The elicitor dose-response curve showed saturation at an elicitor concentration of 1%. At any time during the whole culturing period cells responded to elicitiation but the maximum enzyme activities induced were lower at the late stages. Experiments with different suspension culture strains, a shoot teratoma culture and hydroponically grown sterile photomixotrophic plants were performed to assess the influence of differentiation on constitutive activities of these enzymes and their inducibility by elicitation. Constitutive furanocoumarin accumulation was positively correlated with the level of differentiation. Although induction of PAL, 4-CL and XOMT activity always accompanied induced furanocoumarin accumulation no absolute correlation existed between induced enzyme activities and the induced product level or relative product increase.Abbreviations 4-CL 4-coumarate:CoA ligase - COMT S-adenosyl-l-methionine:caffeic acid 3-O-methyltransferase - PAL phenylalanine:ammonia-lyase - XOMT S-adenosyl-l-methionine:xanthotoxol O-methyltransferase     

rDNA targeted oligonucleotide primers for the identification of pathogenic yeasts in a polymerase chain reaction

Summary Species-specific oligonucleotide primers were designed for PCR identification of the basidiomycetous yeastsCryptococcus neoformans, Trichosporon cutaneum andRhodotorula mucilaginosa. The procedure uses standard PCR components including DNA from the test species and three primers: two universal external (upstream and downstream) limiting primers and a species-specific internal primer. Species identification requires the formation of a species-specific rDNA nucleotide segment that is significantly smaller (200 bp) than a non-target segment (600 bp). The procedure can be used to identify yeasts from single and mixed populations.This paper is dedicated to Professor Herman Jan Phaff in honor of his 50 years of active research which still continues.     

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。     

Ein Beitrag zur Systematik und Entwicklungsbiologie höherer Pilze: Hefe-Typen der Basidiomyceten. Teil II: Microbotryum-Typ

In this and three further papers 205 yeasts and yeast states of Basidiomycetes and presumed relatives were investigated comparatively on the basis of the carbohydrate (neutral sugars) pattern of purified cell walls, urease-activity, diazonium blue B reaction on the production of extracellular amyloid compounds (EAS), fermentation of carbohydrates, and ubiquinone data. A clustering leading to the Protomyces-, the Microbotryum-, the Ustilago-, the Dacrymyces-, and the Tremella-type became apparent, especially from the qualitative and quantitative cell wall carbohydrate pattern. The different yeast types correspond well with 5S rRNA clusters known from the literature. 31 strains clustering within the Microbotryum-type comprise the phragmobasidial smut fungi of dicotyledonous hosts (Microbotryum. Sphacelotheca), the phragmobasidial Rhodosporidium- and Leucosporidium-species including some anamorph Rhodotorula-species, which lack an oxidative degradation of myo-inositol, the genera Sporobolomyces and Sporidiobolus, the Septobasidiales and some simple septate Auriculariales e.g. Agaricostilbum, Platygloea. Main characteristics of the Microbotryum-type are: 1. The absence of extracellular amyloid compounds. 2. The dominance of mannose and the presence of fucose as cell wall constituents. 3. A positive DBB-reaction and splitting of urea. Four Ustilago species parasitic on dicotyledonous hosts were transfered to Microbotryum (M. scabiosae, M. scorzonerae, M. cordae, M. vinosum) as a consequence from cell wall carbohydrate composition, production of rhodotorulic acid, and 5S rRNA sequence data from the literature. The predominance of mannose in the cell wall — otherwise only known from ascomycetous yeasts –, a type A secondary structure of 5S rRNA, a simple unifactorial mating system in all parasitic smut species suggest that the Microbotryum-type might be ancestral to the Ustilago-type. An evolution of simple (“siphonal”) holobasidia from “pseudotrichal” phragmobasidia will be discussed.     

Transport of an anionic substrate by the H+/monosaccharide symport inRhodotorula gracilis: Only the protonated form of the carrier is catalytically active

Summary The yeastRhodotorula gracilis accumulated glucuronate by an H⁺/symport. The transport was electroneutral, driven by the chemical gradient of protons pH. The observed stoichiometry amounted to 1 proton per molecule glucuronate. At pH 4, the half-saturation constantK _T was at its lowest value (K _T =8mm), whereas the maximal velocityV _T reached a maximum (V _T =15 nmol/min×mg dry wt). Monosaccharides competitively inhibited the uptake of glucuronate and vice versa. Hence, the two substrates share the same transport system. The steady-state accumulation of glucuronate reflected the course of the pH gradient. It is concluded that glucuronate is transported as an anionic substrate by the protonated carrier, the driving force being the chemical gradient of the H⁺ (pH). The ternary carrier/H⁺/glc-COOO-complex is electroneutral and independent of the membrane potential. Simultaneous uptake of organic acids (acetic or propionic acid) which is also energized by the pH gradient led to a noncompetitive inhibition of glucuronate transport. Thus, manipulation of the driving force, pH, reducedV _T without affectingK _T . Kinetic and energetic arguments are presented which stronly suggest that only the protonated carrier is catalytically active inR. gracilis.     

提高红酵母胡萝卜素发酵产率的研究

以红酵母RY-998为实验菌株,采用液体摇瓶发酵方式,在培养基中加入氟化铵等6种添加物,研究它们对红酵母和长及胡萝卜素合成的影响。结果表明;除植酸和二甲基亚砜外,氟化铵,醋酸铵,L-亮氨酸和L-缬氨酸对红酵母胡萝卜素产率均有明显的提高作用;当同时添加氟化铵15mg/L,醋酸铵20mg/L,L-亮氨酸40mg/L和L-缬氨酸30mg/L时,细胞生物量,胡萝卜素含量和产率可分别比对照组提高42.2%,55.4%和121.2%。