Torulopsis Holmii Research Articles

Physiological properties of some yeast strains

Twenty yeast strains have recently been isolated in pure cultures from natural and industrial sources and identified based mainly on physiological properties. The majority of the strains (15) are alcohologenic belonging to the genus Saccharomyces and comprise two brewer's (beer) yeast strains (S. carlsbergensis= S. uvarum A and B), two baker's yeast strains (S. cerevisiae CA and CP), one spirit yeast strain (S. cerevisiae CF) and ten wine yeast strains (S. cerevisiae var. ellipsoideus = S. ellipsoideus 1, 3, 4, 6, 8 and 9; S. oviformis 2, 5 and 7; and S. uvarum 10). The other 5 yeast strains belong to different species: Kloeckera apiculate, Candida mycoderma (Mycoderma vini), Pichia membranaefaciens, Rhodotorula glutinis and Torulopsis holmii, respectively.

Sourdough bread production with lactobacilli and S. cerevisiae isolated from sourdoughs

The interactive effects of lactic acid bacteria (LAB) and yeasts were identified through isolation of sourdough sponges. Fourteen sourdough samples were collected from different bakeries in Isparta. Carnobacterium divergens ( Lactobacillus divergens) (6.1%), Lactobacillus brevis (15.1%), Lactobacillus amylophilus (6.1%), Lactobacillus sake (6.1%), Lactobacillus acetotolerans (6.1%) , Lactobacillus plantarum (3.0%), Pediococcus pentosaceus (6.1%) and P. acidilactici (6.1%), Tetragenococcus halophilus ( Pediococcus halophilus) (3.0%) were isolated from sourdoughs as LAB while Saccharomyces cerevisiae (27.0%), S. delbrueckii (2.7%), Torulopsis holmii (10.8%) and T. unisporus (2.7%) were also isolated from sourdough sponges as yeasts. Seven kinds of bread were made with the inoculation 1.5% S. cerevisiae and/or 1.5% lactobacilli ( Lb. amylophilus, Lb. brevis, Lb. plantarum, Lb. sake and Lb. acetotolerans). Six kinds of bread were produced with the mixture of the above five different LAB and S. cerevisiae, and the seventh bread made with S. cerevisiae (commercial culture) alone as control bread. The sample prepared with 1.5% Lb. amylophilus and 1.5% S. cerevisiae showed the best results on rheological properties of bread while that with 1.5% mixed LAB and 1.5% S. cerevisiae was the poorest. LAB used in sourdough breads increased shelf life and delayed staling. In sensory analyses, 1.5% Lb. sake and 1.5% S. cerevisiae application were preferred well by the panel.

The synthesis and characterisation of planar oligophenol with Schiff base substitute

In this study, the oxidative polycondensation reaction conditions of 2- p-tolylazomethinephenol (TAP) with air oxygen and sodiumhypochloride (NaOCl) were studied in an aqueous alkaline medium between 50 and 90 °C. The structure and properties of the products were studied by chemical and spectra analyses. TAP was converted to ditrimers (15–67%) by oxidised in an aqueous alkaline medium. The number average molecular weight ( M n), mass average molecular weight ( M w) and polydispersity index (PDI) values were found to be 6780, 7660 and 1.13, respectively. A part of the azomethine (CHN) group oxidised to carboxylic group (–COOH) during the polycondensation reaction. Thus, reaction product which is oligo-2- p-tolylazomethinephenol (OTAP), involves tolylazomethine and carboxylic (–COOH) (0.5–20%) groups. Besides, oligomer–metal complexes of OTAP with Cu(II), Zn(II), Co(II) and Pb(II) were synthesised and the structure and properties were studied. Antimicrobial activities of the oligomer and its oligomer–metal complexes have been tested against L. monocytogenez, Bacillus brevis, P. vulgaris, E. coli, B. megaterium, M. luteus, B. cereus, K. pneumoniae, M. smegmatis, S. thermophilus, S. aureus, E. aeroginosa and Torulopsis holmii. Also, DTA and TG analyses were shown to be stable for OTAP and its oligomer–metal complexes against thermooxidative decomposition.

The yeast flora of cocoa bean fermentation in the Ivory Coast

The yeast flora involved in the traditional fermentation process of cocoa during four harvest seasons in the Ivory Coast was studied. Twenty-nine species belonging to 11 genera were identified. The following species were the most frequently isolated:Saccharomyces chevalieri,Pichia membranaefaciens, Candida krusei, Torulopsis holmii, Torulopsis Candida. This flora is similar to that found in other parts of the world.

Tolerance of acetate, propionate and sorbate by Saccharomyces cerevisiae and Torulopsis holmii

Several strains of Saccharomyces cerevisiae and one of Torulopsis holmii were investigated with regard to their tolerance of acetate, propionate and sorbate. The S. cerevisiae strains had poor acetic acid tolerance in sour dough pH 4·3, the dough raising power decreasing on average by 67% in the presence of 0·34% sodium acetate, while T. holmii was not affected by this concentration. Propionate (0·16%) and sorbate (0·08%) were more inhibitory than acetate, inhibiting the dough raising power even in normal dough at pH 5·9. Torulopsis holmii also had a good tolerance of propionate and sorbate and seems suitable for raising sour doughs.

Novel Kefir yeast having remarkable sugar utilization. Part I. Identification and fermentation character of Kefir yeast.

A novel yeast KY-5 was isolated from Danish Kefir grains grown in skimmed milk and identified as Torulopsis holmii by the morphological, physiological and chemical method with analyses of its electrophoresis, coenzyme Q system and DNA base composition. Glucose, galactose, mannose and sucrose were fermented by the yeast, but lactose was not fermented. An inductive period was not required for galactose fermentation, even though the yeast was cultivated in a glucose medium. On the other hand, an inductive period was necessary for fructose fermentation. The yeast preferentially metabolized galactose in a glucose and galactose mixed medium. According to Warburg respirometric analyses of the intact cell, protoplast cell and cell free extract of the yeast, the remarkable sugar utilization might be dependent on constituent enzymes involved in the sugar intake and metabolism. The enzymes seemed to be quite different from those of usual yeasts.

Asporogenous yeasts and their supposed ascosporogenous states: An electrophoretic comparison of enzymes.

The relationship of nine Candida species, five Torulopsis species, and five species and two varieties of Kloeckera to the ascosporogenous yeast species considered to be their teleomorphs was studied by electrophoretic comparison of enzymes. Close relationships were seen between fourteen teleomorphs and their anamorphic counterparts, Candida guilliermondii and Pichia guilliermondii, Candida krusei and Issatchenkia orientalis (Pichia kudriavzevii), Candida lambica and Pichia fermentans, Candida melinii and Hansenula wingei, Candida utilis and Hansenula jadinii, Candida macedoniensis and Kluyveromyces marxianus, Candida pseudotropicalis and Kluyveromyces fragilis, Candida parapsilosis (group 2) and Lodderomyces elongisporus, Torulopsis holmii and Saccharomyces exiguus, Torulopsis colliculosa and Torulaspora delbrueckii (Saccharomyces fermentati), Torulopsis stellata and Torulaspora delbrueckii (Saccharomyces rosei), Kloeckera africana and Hanseniaspora vinea, Kloeckera apiculata and Hanseniaspora uvarum, and Kloeckera japonica and Hanseniaspora valbyensis. There was no apparent relation between the four pairs: Candida valida and Pichia membranaefaciens, Candida parapsilosis (group 1) and Lodderomyces elongisporus, Torulopsis molischiana and Hansenula capculata, and Torulopsis candida and Debaryomyces hansenii and Debaryomyces marama. From these results, this zymographic technique is considered to be a useful tool for the study of relalationships between the different states of a yeast species.

Novel Kefir yeast having remarkable sugar utilization. Part II. Hexose-phosphorylating activities of Torulopsis holmii KY-5 isolated from Kefir grain.

Torulopsis holmii KY-5 isolated from Kefir grain had in its constitution two kinds of hexose phosphorylating enzymes: glucokinase and galactokinase, and also had inducible hexokinase induced only by fructose. Unless the hexokinase was induced in the yeast, the galactokinase activity was about 5-9 times as much as glucokinase activity, and therefore this resulted in the preferential utility of galactose over glucose. The induction of hexokinase by fructose was suggested by the inhibitory effects of 2-deoxyglucose for the growth of fructose-grown cells. The hexokinase induction by fructose was also confirmed chromatographically and electrophoretically.

Fate of Spoilage Microorganisms in Frozen and Chilled Concentrated Tomato Juices

Survival of four potential spoilage organisms was studied in tomato concentrates (22°, 28° and 34° Brix) stored at +7. 0 and −18 C for 4 months. In concentrates stored at −18 C, viable counts of Lactobacillus plantarum remained practically stable whereas those of Leuconostoc mesenteroides declined rapidly during the storage period, its death rate being reduced as the juice concentration was increased. Viable counts of Candida krusei and even more so of Torulopsis holmii, decreased progressively during frozen storage. In concentrates held at 0 C, viable counts of the four test organisms decreased during storage, regardless of the juice concentration. but at +7 C, for three out of the four test organisms, the ability to spoil the concentrates was dependent on the juice concentration.

Candida milleri sp. nov.

Three strains of yeast previously identified as Torulopsis holmii were found to have a considerably higher guanine-plus-cytosine content than the type and other strains of this species and are described as a new species, Candida milleri.

Microorganisms of the San Francisco Sour Dough Bread Process

Two hundred isolates from San Francisco sour dough French bread fermentations (40 from each of five different bakeries) were screened by fermentation tests and for their ability to grow in the presence of cycloheximide (Actidione). All of the isolates from four of the bakeries and 70% of those from the fifth were unable to utilize maltose but grew well on other sugars, even in the presence of cycloheximide. The remaining few isolates from the fifth bakery utilized maltose but not galactose and were inhibited by cycloheximide. No bakers' yeast types were found. Sixteen of the maltose-negative and five of the galactose-negative isolates were subjected to more rigorous taxonomic procedures. All of the maltose-negative isolates were identified as asporogenous strains of Saccharomyces exiguus ( Torulopsis holmii ) and the galactose-negative ones, as S. inusitatus . The predominance of S. exiguus , its vigor in the particular acidic environment of the sour dough, and the correlation of its numbers with the leavening function constitute strong evidence on the role of this organism in the sour dough system.

Microorganisms of the San Francisco Sour Dough Bread Process

Two hundred isolates from San Francisco sour dough French bread fermentations (40 from each of five different bakeries) were screened by fermentation tests and for their ability to grow in the presence of cycloheximide (Actidione). All of the isolates from four of the bakeries and 70% of those from the fifth were unable to utilize maltose but grew well on other sugars, even in the presence of cycloheximide. The remaining few isolates from the fifth bakery utilized maltose but not galactose and were inhibited by cycloheximide. No bakers' yeast types were found. Sixteen of the maltose-negative and five of the galactose-negative isolates were subjected to more rigorous taxonomic procedures. All of the maltose-negative isolates were identified as asporogenous strains of Saccharomyces exiguus (Torulopsis holmii) and the galactose-negative ones, as S. inusitatus. The predominance of S. exiguus, its vigor in the particular acidic environment of the sour dough, and the correlation of its numbers with the leavening function constitute strong evidence on the role of this organism in the sour dough system.

Serological classification of the genusTorulopsis

Antigenic analyses of 4 species of Torulopsis were carried out by the slide agglutination method using monospecific and absorbed antisera homologous to antigens of the genus Candida. The antigenic structure of each species was confirmed by reciprocal or successive absorption and slide agglutination test. Torulopsis stellata var. cambresieri and T. colliculosa possess the thermostable antigens 1, 3, 4 and 24, but no thermolabile antigen. Their antigenic structures were identical to those of Saccharomyces rosei and S. fermentati, respectively, despite the biological differences among them. Torulopsis holmii has thermostable antigens 1, 3, 4, 5, 6, 10 and 26, but no thermolabile antigen. The antigenic structure of this species is similar to that of S. exiguus. Torulopsis glabrata contains the thermostable antigens 1, 3, 6, 10 and 34, and thermolabile antigen k. In a comparative study, the antigenic structures of many strains coincided with those of the standard when they were analyzed with monospecific antis...