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This study identified phenotypic traits appropriate for biotechnological applications of 118 yeasts isolated from cachaça distilleries. Different properties were verified: capacity to use alternative carbon sources; ability to tolerate high concentrations of sucrose, ethanol, methanol, aluminum and zinc as well as different pH values and foam production. Pichia guilliermondii and Pichia anomala strains were identified as the most promising ones for application in the second-generation biofuel industry, showing ability to grow on high glycerol concentrations. Other isolates, identified as Saccharomyces cerevisiae, produced bioethanol comparable to the industrial strains, and were therefore ideal for use in the first-generation ethanol industry. Some of these strains also showed high resistance to aluminum, as observed in sugarcane juice, and to inter-cycle washings with diluted sulphuric acid, as performed in the industrial bioethanol production process. In summary, yeast isolates from cachaça distilleries displayed robustness and phenotypic plasticity, which makes them interesting for biotechnological applications. [ABSTRACT FROM AUTHOR]

In the present investigation, we have attempted to identify the potential two epiphytic yeast strains for growth promotion and management of chilli fruit rot. Seed treatment withPichia guilliermondiishowed increased seedling vigour index (55%), fresh weight (96%) and dry weight (45%) over untreated control. Furthermore,P. guilliermondiishowed higher root colonisation ability, indole-3-acetic acid (IAA) production and phosphate solubilisation ability. On the other hand, seedling dip withHanseniaspora uvaruminduced higher levels of defence-related compounds in chilli seedlings challenge-inoculated withColletotrichum capsiciunder glasshouse conditions. Among the different media tested, higher biomass ofP. guilliermondiiandH. uvarumwas obtained in pine juice broth and sugarcane juice broth, respectively. Glycerol buffer formulation showed viability (>70%) ofP. guilliermondiiup to 4 months andH. uvarumup to 9 months when stored at ambient conditions. Seedling dip and foliar sprays withH. uvarumshowed 37– 40% reduction in chilli fruit rot incidence under field conditions. It also showed higher (cumulative) accumulation of defence-related compounds in chilli leaves and ripe fruits under field conditions. The results of current investigation indicated a clear difference among the two epiphytic yeast strains.P. guilliermondiiwas identified as growth promoter of chilli andH. uvarumas antagonist of chilli fruit rot pathogen,C. capsici. [ABSTRACT FROM PUBLISHER]

The growth of Pichia guilliermondii yeast Levica 27 strain was studied for its use as microbial additive in ruminant animals. Therefore, yeast growth in NRF medium and malt extract were compared. Then, their development was evaluated when carbohydrates and nitrogen sources varied in the formulation of NRF medium. In sugars, the glucose was substituted by sucrose and lactose and in case of nitrogen the tryptone was substituted by ammonium sulfate, casein and urea. There was not interaction between treatments and the time of study for the count of Levica 27cells in malt extracts and NRF solutions, and there were not differences between both media. In NRF medium, the best growths were achieved when glucose and sucrose were used at 72h and the last one decreased the pH of the medium (P ? 0.001).The casein and urea caused higher growth (P ? 0.001) after 48h, but urea caused increase of pH. It is concluded that the strain Levica 27 growth was higher before glucose or sucrose, casein or urea. Studies are recommended to design an economical mean of culture with national sources that allows the obtaining of a preparation with Levica 27 with additive effect on ruminants. [ABSTRACT FROM AUTHOR]

In previous studies it was shown that Pichia guilliermondii strain Z1, isolated from healthy Moroccan citrus Valencia-Late oranges, was effective against Pénicillium italicum. Here the effectiveness of strain Z1 was assessed against Pénicillium digitatum, the causal agent of green mould, under different temperature (5-25°C) and relative humidity (RH) (45-100%) regimes for its reliable and largescale application in packinghouse. All main effects and interactions were significant (P<0.0001). In the pathogen control, the largest lesion diameter was at an RH range between 98 and 100%, regardless of the incubation temperature. The efficacy of strain Z1 was not dependent on the environment and reduced disease incidence by >80%. Its applications as a formulated product significantly reduced the incidence of infected fruit (55%) and the percentage of infected wounds (47%) compared to the only pathogen control treatment. However, disease control with formulated product was significantly less than that obtained with thiabendazole (30%) or strain Z1 culturable cells (35%). These results highlight that strain Z1 is an effective biological control agent for control of green mould under varying environmental conditions, and control may be optimized by combining its use with other environmentally-safe post-harvest treatments or improved formulation. [ABSTRACT FROM AUTHOR]

Abstract: Pichia guilliermondii strain Z1, which was previously proven to be effective against blue mold of citrus fruit, has been further tested in controlled conditions to determine whether the yeast, as an alternative for synthetic fungicides, would be compatible with other postharvest practices used commercially. In particular, commercial fruit waxes can reduce their survival and effectiveness. The commercial fruit waxes tested, in combination at 20% with strain Z1, included microcrystalline, ester gum, candelilla, beeswax, montan, paraffin, rice bran, rosin maleic, carnauba, shellac, and one mixture shellac plus carnauba. Beeswax, paraffin, rosin maleic, carnauba, and shellac increased significantly strain Z1 survival in Petri dish assays. Candelilla, beeswax, rice bran, rosin maleic, carnauba, shellac, and shellac–carnauba mixture did not significantly reduce the strain Z1 yield on orange fruit surfaces compared to other waxes. With the exception of rosin maleic wax, none of the commercial fruit waxes or mixture increased significantly the ability of the formulated product of strain Z1 to control the postharvest pathogen Penicillium italicum on wounded orange fruit. When the formulated product of strain Z1 was used in combination with beeswax, strain Z1 retained the same efficacy. In contrast, microcrystalline, ester gum, candelilla, montan, paraffin, rice bran, carnauba, shellac, and shellac-carnauba mixture significantly reduced the effectiveness of the formulated product of strain Z1. No antibiosis was detected for strain Z1 against P. italicum. Strain Z1 inhibited the spore germination for the low juice concentration (up to 5%) when compared to the control. However, the addition of fresh juice after antagonist removal allowed the restoration of the germination of P. italicum spores; suggesting the possibility of competition for nutrients in the biocontrol activity of strain Z1. The study demonstrates the potential commercial application of strain Z1 with beeswax and rosin maleic wax for postharvest control of citrus blue mold. As biocontrol relies on competition for nutrients, an enriched formulation with nutrients is needed for reliable antifungal activity of this yeast strain. [Copyright &y& Elsevier]

Ninety nine yeast isolates were isolated from surface of mango fruits and were tested in vivo in preliminary study for biocontrol potential of Lasiodiplodia rot of mango fruits. According to primary screening, nine isolates were selected to continue the secondary screening using different concentrations of the washed yeast cells in water suspension to study their biocontrol efficacy at 16±1°C. It was found that using washed cells of yeast isolate Mg 147 (Candida multisgemmis) at 1x109, 5x108 and 2x108 CFU/ml produced complete protection for 14 days to wounds of mango fruit inoculated with spore suspension of the fungus Lasiodiplodia theobromae 1x105 conidia/ml. Meantime, no lesion developed on the mango fruit treated with the isolates Mg 39 (Pichia guilliermondii strain A) at the highest tested colony forming unit (CFU) levels, i.e. 1x109 and 5x108 CFU/ml. Supernatant of the yeast cultures, tested in secondary screening, did not prevent spore germination of L. theobromae or decay of wounded mango fruit but had inhibitory effect. However, 1- Methylcyclopropene (1-MCP) treatment significantly reduced the infected area mm2 on mango fruit inoculated with L. theobromae (1x105 conidia/ml) during the 14 days of storage at 16±1°C and improved efficacy of isolates Mg147 and Mg39. When applied as combined treatments between 1- MCP and biocontrol agents, no lesion developed on the fruit treated with the isolate Mg 147 at 1x 108 CFU/ml or higher. Meanwhile, no lesion developed on the fruit treated with the isolate Mg 39 at 2x 108 CFU/ml or higher while, the percentages of rot reduction were ranged between 94.1% - 81.3% for concentrations 1x108 and 6.6x107 CFU/ml respectively. [ABSTRACT FROM AUTHOR]

Highlights: [•] Sixty-two yeasts were isolated from rice seeds. [•] Four yeasts showed high efficacy in reducing bakanae incidence and severity. [•] A strain of Pichia guilliermondi resulted the most effective antagonist. [•] The combined use of thermotherapy and yeasts increased the biocontrol efficacy. [•] Both the antagonists and hot water treatment showed a seed priming effect. [ABSTRACT FROM AUTHOR]

The potential for using Pichia guilliermondii BCC 5389 or Bacillus subtilis ABS-S14 by themselves or in combination for the control Penicillium digitatum in citrus, and their effects on postharvest quality of fruit was investigated. The percentage of disease with the combined antagonists was completely inhibited. Rapid colonization of P. guilliermondii was observed in the wounds during the first day to 6 days at 25oC, whereas B. subtilis, increased marginally over 3 days. The populations then stabilized for the remaining incubation period. The percentage of spore germination of P. digitatum incubated with all treatments was inhibited by 100%. At concentrations of the combined antagonists of 1x108 CFU/mL, the incidence of green mould was reduced to 0% compared with the pathogen control itself (92.93%) after 5 days of incubation at 25oC. The combination did not impair any of the quality parameters of fruit following incubation at 25oC for 7 days. [ABSTRACT FROM AUTHOR]

This study suggests a new effective chemical pretreatment to hydrolyze rice straw for efficient ethanol production. It introduces a new yeast strain that ferments rice straw hydrolyzate more efficiently than Saccharomyces cerevisiae. The results proved the effectiveness of alkali application before HCl to delignify rice straw and to make it more appropriate for hydrolysis. The application of the hydrolyzing enzymes (cellulase and pectinase) resulted in hydrolysis of pretreated rice straw up to 94.3%. The total sugars released due to pretreatment-enzyme system was about 624 mg g-1 dry mass and the glucose fraction was 198 mg g-1. The results indicated that Pichia guilliermondii is more effective to ferment rice straw hydrolyzate than S. cerevisiae. P. guilliermondii produced larger amounts of bioethanol (7.72 g L-1) than S. cerevisiae (6.13 g L-1) under the same conditions. Our results suggest an appropriate pretreatment system (the cold dilute alkali-acid) and a new effective yeast strain to ferment the rice straw hydrolyzate to produce large amounts of bioethanol. [ABSTRACT FROM AUTHOR]

Highlights: [•] A robust yeast strain was obtained by adaptation to lignocellulosic hydrolysate. [•] High ethanol titer and productivity were reached by repeated fed-batch fermentation. [•] Ethanol was produced efficiently without external nutrient addition or detoxification. [Copyright &y& Elsevier]

Aims Dekkera bruxellensis and Pichia guilliermondii are contaminating yeasts in wine due to the production of phenolic aromas. Although the degradation pathway of cinnamic acids, precursors of these phenolic compounds has been described in D. bruxellensis, no such pathway has been described in P. guilliermondii. Methods and Results A molecular and physiological characterization of 14 D. bruxellensis and 15 P. guilliermondii phenol-producing strains was carried out. Both p-coumarate decarboxylase ( CD) and vinyl reductase ( VR) activities, responsible for the production of volatile phenols, were quantified and the production of 4-vinylphenol and 4-ethylphenol were measured. All D. bruxellensis and some P. guilliermondii strains showed the two enzymatic activities, whilst 11 of the 15 strains of this latter species showed only CD activity and did not produce 4- EP in the assay conditions. Furthermore, PCR products obtained with degenerated primers showed a low homology with the sequence of the gene for a phenyl acrylic acid decarboxylase activity described in Saccharomyces cerevisiae. Conclusions D. bruxellensis and P. guilliermondii may share a similar metabolic pathway for the degradation of cinnamic acids. Significance and Impact of the Study This is the first work that analyses the CD and VR activities in P. guilliermondii, and the results suggest that within this species, there are differences in the metabolization of cinnamic acids. [ABSTRACT FROM AUTHOR]

Chiral secondary alcohols with additional functional groups are frequently required as important and valuable synthons for pharmaceuticals, agricultural and other fine chemicals. With the advantages of environmentally benign reaction conditions, broad reaction scope, and high stereoselectivity, biocatalytic reduction of prochiral ketones offers significant potential in the synthesis of optically active alcohols. A CmCR homologous carbonyl reductase from Pichia guilliermondii NRRL Y-324 was successfully overexpressed. Substrate profile characterization revealed its broad substrate specificity, covering aryl ketones, aliphatic ketones and ketoesters. Furthermore, a variety of ketone substrates were asymmetrically reduced by the purified enzyme with an additionally NADPH regeneration system. The reduction system exhibited excellent enantioselectivity (>99% ee) in the reduction of all the aromatic ketones and ketoesters, except for 2-bromoacetophenone (93.5% ee). Semi-preparative reduction of six ketones was achieved with high enantioselectivity (>99% ee) and isolation yields (>80%) within 12 h. This study provides a useful guidance for further application of this enzyme in the asymmetric synthesis of chiral alcohol enantiomers. [ABSTRACT FROM AUTHOR]

The coffee fermentation is characterized by the presence of different microorganisms belonging to the groups of bacteria, fungi and yeast. The objectives of this work were to select pectinolytic microorganisms isolated from coffee fermentations and evaluate their performance on coffee pulp culture medium. The yeasts and bacteria isolates were evaluated for their activity of polygalacturonase (PG), pectin lyase (PL) and pectin methylesterase (PME) and metabolites production. Among 127 yeasts isolates and 189 bacterial isolates, 15 were pre-selected based on their ability to produce PL and organic compounds. These isolates were strains identified as Bacillus cereus, Bacillus megaterium, Bacillus subtilis, Candida parapsilosis, Pichia caribbica, Pichia guilliermondii and Saccharomyces cerevisiae. When cultivated in Coffee peel and pulp media in single culture or two by two mixed inocula, different behavior concerning to PME, PL and PG were found. The two principal components PC1 and PC2 accounted for 45.27 and 32.02 % of the total variance. UFLA CN727 and UFLA CN731 strains were grouped in the positive part of PC1 being characterized by 1,2-propanediol, hexanoic acid, decanoic acid, nonanoic acid and ethyl acetate. The UFLA CN448 and UFLA CN724 strains were grouped in the negative part of PC1 and were mainly characterized by guaiacol, butyric acid and citronellol. S. cerevisiae UFLACN727, P. guilliermondii UFLACN731 and C. parapsilosis UFLACN448 isolates are promising candidates to be tested in future studies as coffee starter cultures. [ABSTRACT FROM AUTHOR]

Abstract: The roles of salt-tolerant yeasts such as Zygosaccharomyces rouxii, Candida versatilis, and Candida etchellsii in the production of volatile flavor compounds (VFCs) in soy sauce fermentation have been well documented. However, the knowledge of VFC production by other salt-tolerant yeasts is still limited. In this work, the roles of Z. rouxii and Pichia guilliermondii strains in VFC production were investigated in moromi medium as a model system for soy sauce fermentation. Inoculation of a single culture of either Z. rouxii or P. guilliermondii as well as co-cultures of these two yeasts into moromi medium showed increased numbers of viable yeast at around 0.7 to 1.9 log CFU/mL after 7days of cultivation at 30°C. During cultivation, both single and co-cultures displayed survival over a 7-day time period, compared with the controls (no culture added). Overall, yeast inoculation enhanced the production of VFCs in the moromi media with higher amounts of ethanol, alcohols, furanones, esters, aldehyde, acid, pyrone and phenols, known as important characteristic flavor compounds in soy sauce. Moreover, the co-culture produced more alcohols, furanones, esters, maltol and benzoic acid than the single culture of Z. rouxii. [Copyright &y& Elsevier]

In this study, the yeasts Pichia guilliermondii and Candida membranifaciens in combination with salicylic acid (SA) were tested for biological control against Penicillium expansum at 20°C. In vitro studies showed that SA at 200 μg/mL had reduced the mycelial growth of pathogen significantly. SA at 10, 50 and 100 μg/mL increased the population of P. guilliermondii while it reduced the population of C. membranifaciens. In vivo studies showed that although both P. guilliermondii and C. membranifaciens had potential to control blue mould, combination of P.guilliermondii with SA at 50 μg/mL and C. membranifaciens with SA at 5 μg/mL improved their efficacy. Our results showed that SA at 5 μg/mL had no effect on P. guilliermondii and C. membranifaciens after 7 days, while at 50 μg/mL reduced the population of P. guilliermondii, and SA at concentration higher than 10 μg/mL reduced the population of C. membranifaciens after 15 days at 20°C. [ABSTRACT FROM PUBLISHER]

A heat-labile phenolic acid decarboxylase from Candida guilliermondii (an anamorph of Pichia guilliermondii) was purified to homogeneity by simple successive column chromatography within 3 days. The molecular mass was 20 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 36 kDa by gel-filtration chromatography, suggesting that the purified enzyme is a homodimer. The optimal pH and temperature were approximately 6.0 and 25°C. Characteristically, more than 50% of the optimal activity was observed at 0°C, suggesting that this enzyme is cold-adapted. The enzyme converted p-coumaric acid, ferulic acid, and caffeic acid to corresponding products with high specific activities of approximately 600, 530, and 46 U/mg, respectively. The activity was stimulated by Mg ions, whereas it was completely inhibited by Fe, Ni, Cu, Hg, 4-chloromericuribenzoate, N-bromosuccinimide, and diethyl pyrocarbonate. The enzyme was inducible and expressed inside the cells moderately by ferulic acid and p-coumaric acid and significantly by non-metabolizable 6-hydroxy-2-naphthoic acid. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate free radical scavenging capacity of crude extracts from forest basidiomycetous fungi, domestic zygomycetous fungi and marine ascomycetous fungi. Lethal concentration values that kill 50% of the brine shrimps (LC50) were determined from 19 fungal extracts using brine shrimp test (BST). The LC50 values of fungal extract ranged between 0.28– 40μg/ml. The basidiomycetous (Lactarius volemoides) was the most toxic fungi with LC50 of 0.28μg/ml while ascomycete Pichia guilliermondii showed the least toxicity with LC50 of 40μg/ml. The concentrations of eleven fungal extracts were further evaluated on their ability to scavenge free radical using 1-diphenyl-2-picrylhydrazyl (α,α-diphenyl-β-picrylhydrazyl) (DPPH) as a dye reagent for spectrophotometric assay at 517nm. The extract concentrations that decreased the initial DPPH radical by 50% (EC50) were determined. The EC50 values ranged from 19–60.4μg/ml ascorbic acid equivalents. Extracts from an edible but undomesticated basidiomycetous fungus isolated from Miombo forest and identified as Termitomyces microcarpus showed the highest scavenging effect with EC50 at 19μg/ml while that from ascomycete Candida tropicalis showed the least EC50 at 60.4μg/ml. These results draw attention to wild undomesticated Miombo fungi as potential source of nutritional supplements worth further investigation. [ABSTRACT FROM AUTHOR]

Abstract: The efficacy of Pichia guilliermondii strain M8 against Botrytis cinerea on apples was evaluated under storage conditions, and its possible modes of action were investigated both in vitro and in vivo experiments. After storage at 1°C for 120days, M8 reduced grey mold incidence from 45.3% (control) to 20.0%. In apple juice medium (AJM) and in wound-inoculated apples, M8 at 109 and 108 cells ml−1 inhibited the spore germination of B. cinerea and the grey mold development. When co-culturing B. cinerea in vitro or in vivo in the presence of the yeast, neither inactivated cells nor culture filtrate of the yeast had any effect on spore germination or germ tube elongation. In AJM, the spore germination was significantly recovered by the addition of 1% glucose, sucrose and fructose, or 0.5% and 1% of (NH4)2SO4, phenylalanine and asparagine. When the pathogen and the yeast were co-incubated in apple wounds with addition of the same nutrients, the inhibition of rots was significantly reduced by the supplemental nutrients. Light microscopy revealed that the yeast strongly adhered to the hyphae and spores of B. cinerea. M8 produced hydrolytic enzymes, including β-1,3-glucanase and chitinases in minimal salt media with different carbon sources. Pretreatment with M8 at 108 cells ml−1 followed by washing, significantly reduced grey mold lesions, suggesting an induction of defense responses. Direct attachment, competition for nitrogen and carbon sources, secretion of hydrolytic enzymes and induction of host resistance play a role in the biocontrol mechanism of P. guilliermondii M8 against B. cinerea. [Copyright &y& Elsevier]

Abstract: To gain insight into the antagonistic molecular mechanisms displayed by the biocontrol epiphytic-yeast Pichia guilliermodii (isolate LCBG-03), its patterns of gene expression were evaluated during direct and indirect induction with Penicillium digitatum EfiA, a well-known fungal phytopathogen during the postharvest processing of citrus. Assays of in vitro antagonistic activity indicated a strong inhibitory effect on fungal growth and spore germination by the yeast, even when yeast–fungus interaction was performed on a rich medium. Antagonist gene expression was evaluated in induced condition as well as in direct interaction using differential expressed sequence tags (ESTs) obtained by two methodologies; suppression subtractive hybridization (SSH) and differential display (DD). We obtained the genetic response of the yeast under three different specific metabolic conditions: starvation by carbon source competence, sensing of extracellular metabolites produced by active mycelium of P. digitatum (membrane system) and induction by fungal cell walls. As a result, we observed just one EST, associated as expected to energy metabolism in starvation conditions; for the membrane system, seven ESTs were obtained by the SSH methodology, all related with some of the following metabolic networks: energy, nitrogen, cell cycle, ABC transporters, response to stress and one unknown sequence. The induced (fungal cell walls) system produced the highest number of ESTs, with a total of 22, including all the metabolic networks mentioned above for the membrane system plus ESTs associated with signal transduction. [Copyright &y& Elsevier]

Post-harvest pathogens cause major losses in apple production. Biological control by using epiphytic yeasts against Penicillium expansum has been considered as an alternative method for controlling the post-harvest decays. The yeast isolates Rhodotorula mucilaginosa, Pichia guilliermondii, which showed high biocontrol efficacy against P. expansum, were selected for formulation tests. Formulation is an important step in developing a biocontrol product. The successful delivery of biocontrol agents, shelf life, stability and effectiveness in commercial conditions depend on the formulation. In the formulation, the carrier is the primary material used to allow a bioproduct to be dispersed effectively. Yeast isolates were grown in a cane molasses-based medium. Harvested yeast cells were combined with inorganic (talk, kaolin) and organic (Rice bran, wheat bran) carriers. Viability of the yeast cells in formulations stored at 4°C and 24°C was determined each month during 6 months storage. After 6 months storage to evaluate efficacy of formulations, all formulations were tested on apple to control blue mold in storage condition. High stability of antagonistic yeasts was achieved by using organic and inorganic carriers. Rice bran and wheat bran stimulated the germination of the yeasts cells during storage period. Both of the yeasts had significantly highest viable yeast cell content over 6 months in formulation containing wheat bran as a carrier. P.guillermondii in all formulations had significantly higher shelf life and was effective than R. mucilaginosa. [ABSTRACT FROM AUTHOR]

Abstract: The nematicidal effect of Pseudomonas fluorescens, Paecilomyces lilacinus, Pichia guilliermondii and Calothrix parietina singly or in combination was tested against root-knot nematode, Meloidogyne incognita. Treatments with P. fluorescens and P. lilacinus caused mortality of M. incognita as 45% and 30% of juveniles after 48 h of exposures, respectively compared to water control in vitro. Under greenhouse conditions, all treatments reduced the disease severity and enhanced plant growth compared to untreated control. Application of P. fluorescens, P. lilacinus and P. guilliermondii Moh 10 was more effective compared to C. parietina. There was a negative interaction between C. parietina and either P. lilacinus or P. guilliermondii. Fresh and dry weight of shoots and roots of plants were significantly reduced as a result of infection with M. incognita, however application of biocontrol agents singly or in mix recovered this reduction. Moreover, they enhanced the growth parameters compared with the control. Our results proved that application of different biocontrol agents (P. fluorescens, P. lilacinus and P. guilliermondii) not only has a lethal effect on nematode, but also enhances the plant growth, supplying many nutritional elements and induction the systemic resistance in plants. Presence of C. parietina as a soil inhabitant cyanobacterium could antagonize biocontrol agents leading to the reduction of their practical efficiency in soil. [Copyright &y& Elsevier]

Abstract: Zinc is an essential nutrient that plays an important role in several biological processes of living organisms. When bound to an organic substrate, Zn is more efficiently absorbed by organisms, has a high biological activity and a low toxicity. Due to its ability to incorporate metals, yeast biomass has been used frequently as a delivery vehicle for many mineral supplements. This study describes the screening of strains of yeast for production of biomass enriched with Zn by submerged fermentation. Five strains of yeasts, belonging to the genera Saccharomyces, Kluyveromyces and Pichia, were evaluated. The highest Zn concentration was 6820mg/kg of dry weight biomass, using Pichia guilliermondii Wickerham LPB 063 after 120h of cultivation in a medium with 0.5g/L ZnSO4. Process conditions were optimized using statistical experimental design methodology. Four parameters were identified in the 28−4 fractional factorial design as having a significant effect on Zn accumulation: ZnSO4 and Fe2(SO4)3 concentrations, time of addition of the ZnSO4 solution and concentration of soybean molasses. In the 32 experimental design, the influence of ZnSO4 and Fe2(SO4)3 concentrations were studied more closely. The highest Zn concentration (75,090mg/kg dry weight) in the biomass was reached using the conditions: ZnSO4, 10.0g/L; Fe2(SO4)3, 0.1g/L in Erlenmeyer flasks. A batch liquid fermentation was carried out in a 2L bioreactor for production of P. guilliermondii Wickerham LPB 063 containing organically bound Zn. The concentration of organically bound Zn after 144h of fermentation was of 96,030mg/kg, with a biomass production of 30g/L. The maximum specific growth rate obtained (μ max) was 0.0077/h, while the maximum productivity of biomass was at 0.1511g/L/h. [ABSTRACT FROM AUTHOR]

The purpose of this study was to characterize the α--rhamnosidase of Pichia guilliermondii NPCC1053 indigenous wine strain from North-Patagonian region. The optimization of yeast culture conditions was carried out and the effects of oenological parameters on α--rhamnosidase activity were evaluated. Additionally, the effect of direct contact with must and wine on α--rhamnosidase activity was assayed. This strain showed an intracellular inducible α--rhamnosidase activity. This enzyme was active at pH, glucose and SO concentrations usually found at the beginning of the fermentation as well as retained high levels of activity after 24 h of incubation in must. Furthermore, P. guilliermondiiα--rhamnosidase was able to release monoterpenols and alcohols from grape glycosidic extracts. The α--rhamnosidase belonging to P. guilliermondii indigenous wine yeast strain showed mainly an intracellular location and evidenced interesting oenological characteristics. This study contributes to the knowledge of α--rhamnosidases from yeast origin because at present, there are few reports about this enzymatic activity in these micro-organisms. In addition, this work is relevant to the regional wine industry considering that this enzyme could be used in the production of more aromatic young wines. [ABSTRACT FROM AUTHOR]

Three steroids and one nordammarane triterpenoid were isolated for the first time from the endophytic fungus Pichia guilliermondii Ppf9 derived from the medicinal plant Paris polyphylla var. yunnanensis. By means of physicochemical and spectrometric analysis, they were identified as ergosta-5,7,22-trienol (1), 5α,8α-epidioxyergosta-6,22-dien-3β-ol (2), ergosta-7,22-dien-3β,5α,6β-triol (3), and helvolic acid (4). Both microdilution-colorimetric and spore germination assays were employed to evaluate their antimicrobial activity. Among them, helvolic acid (4) exhibited the strongest antibacterial activity against all test bacteria, with MIC values ranging from 1.56 μg/mL to 50 μg/mL, and IC50 values from 0.98 μg/mL to 33.19 μg/mL. It also showed strong inhibitory activity on the spore germination of Magnaporthe oryzae with an IC50 value of 7.20 μg/mL. Among the three steroids, 5α,8α-epidioxyergosta-6,22-dien-3β-ol (2) exhibited relatively strong antimicrobial activity. The results suggest that the endophytic fungus Pichia guillermondii Ppf9 could be a candidate for producing helvolic acid, and the metabolites from this fungus could be potentially developed as antimicrobial agents in the future. [ABSTRACT FROM AUTHOR]

Aims: To investigate whether the presence of Pichia guilliermondii impacts on the production of volatile phenols from mixed wine fermentations with Dekkera bruxellensis and Saccharomyces cerevisiae. Methods and Results: Four inoculation strategies were performed in small-scale fermentations involving P. guilliermondii, D. bruxellensis and S. cerevisiae using Syrah grape juice supplemented with 100 mg l−1 of p-coumaric acid. High pressure liquid chromatography was used for the quantification or volatile phenols. Significant high levels of 4-ethylphenol and 4-ethylguaicol (720 and 545 μg l−1, respectively), as well as the highest levels of 4-vinylphenol (>4500 μg l−1), were observed when P. guilliermondii species was inoculated from the beginning of the fermentation. Conclusions: The metabolic interaction occurring between the high vinylphenol producer species P. guilliermondii and D. bruxellensis exhibiting a high vinylphenol reductase activity resulted in an increased production of volatile phenols in wine. Significance and Impact of the Study: Pichia guilliermondii must be considered a very important spoilage yeast in the wine industry capable of producing large amounts of volatile phenols. [ABSTRACT FROM AUTHOR]

Abstract: Nine different combinations of mugi koji (barley steamed and molded with Aspergillus oryzae) and halotolerant microorganisms (HTMs), Zygosaccharomyces rouxii, Candida versatilis, and Tetragenococcus halophilus, were inoculated into chum salmon sauce mash under a non-aseptic condition used in industrial fish sauce production and fermented at 35 ± 2.5 °C for 84 days to elucidate the microbial dynamics (i.e., microbial count and microbiota) during fermentation. The viable count of halotolerant yeast (HTY) in fermented chum salmon sauce (FCSS) mash showed various time courses dependent on the combination of the starter microorganisms. Halotolerant lactic acid bacteria (HTL) were detected morphologically and physiologically only from FCSS mash inoculated with T. halophilus alone or with T. halophilus and C. versatilis during the first 28 days of fermentation. Only four fungal species, Z. rouxii, C. versatilis, Pichia guilliermondii, and A. oryzae, were detected throughout the fermentation by PCR-denaturing gradient gel electrophoresis (PCR-DGGE). In FCSS mash, dominant HTMs, especially eumycetes, were nonexistent. However, under the non-aseptic conditions, undesirable wild yeast such as P. guilliermondii grew fortuitously. Therefore, HTY inoculation into FCSS mash at the beginning of fermentation is effective in preventing the growth of wild yeast and the resultant unfavorable flavor. [Copyright &y& Elsevier]

Abstract: Pichia guilliermondii strain R13, a yeast isolated from Thai rambutan, has been shown to suppress the fungal pathogen Colletotrichum capsici in harvested chili. Its multiple modes of action include nutrient competition, tight attachment to the fungus, and hydrolytic enzyme secretion. This study investigated the ability of the P. guilliermondii strain R13 to induce resistance against C. capsici in chili fruit. The pretreatment of chili with the yeast antagonist, physically separated from the fungus by known distances, significantly reduced disease incidence and lesion diameter caused by C. capsici. Compared to the controls, the yeast treatment also significantly enhanced the activities of phenylalanine ammonia-lyase, chitinase, and β-1,3-glucanase, and the accumulation of capsidiol phytoalexin in chili tissue. Scanning electron micrographs showed that the morphology of C. capsici spores and hyphae were abnormal and that the pathogen had restricted growth on chili tissue adjacent to the yeast-inoculated sites. The results indicate that the induction of resistance may be another mechanism by which the yeast antagonist suppresses C. capsici. [Copyright &y& Elsevier]

Abstract: Xylitol production from xylose by a self-isolated furfural and 5-hydroxymethyl furfural assimilating Pichia guilliermondii was studied under oxygen limitation. An extremely low initial volumetric oxygen transfer coefficient (0.075 h−1) was found most favorable to the xylitol production with yield of 0.61 g g−1. Related enzymes activities were also investigated and discussed. [Copyright &y& Elsevier]

Abstract: This study investigated the effectiveness of heat treatment and Pichia guilliermondii, either alone or in combination, to combat postharvest fungal spoilage in cherry tomato fruit. In vitro experiments demonstrated that heat treatment at 38°C significantly inhibited mycelial growth of three different pathogens (Botrytis cinerea, Alternaria alternata and Rhizopus stolonifer Ehrenb). In vivo experiments unveiled that either heat treatment or P. guilliermondii reduced decay caused by these pathogens. Furthermore, a combination of heat treatment followed by the application of P. guilliermondii (H+P) provided the best efficacy in prevention of cherry tomato from fungal spoilage. Following, H+P treatment, electronic nose detected a reduction of volatility in cherry tomato fruit odor, an indicator of preserving fruit''s freshness. Scanning electron microscopy unveiled that heat treatment at 38°C for 24h inhibited hyphae growth and spore germination of R. stolonifer Ehrenb while P. guilliermondii multiplied rapidly on fruit wounds, and its cells had a strong capability of adhesion to the hyphae of R. stolonifer Ehrenb. However, heat treatment also seriously injured P. guilliermondii, therefore P. guilliermondii should be applied after heat treatment. A combination of heat treatment and P. guilliermondii is one of the most effective techniques at controlling postharvest fungal spoilage in cherry tomato fruit. [Copyright &y& Elsevier]

Abstract: The inulinase gene cloned from the marine-derived yeast Pichia guilliermondii strain 1 was expressed in Pichia pastoris X-33 and the conditions for overexpression of the inulinase were optimized. After the optimization of the conditions for production of the recombinant inulinase, 286.8±5.4U/ml and 8873±55.3U/mg of the recombinanat inulinase in the supernatant of the culture of 2-l fermentor were attained at 120h of the fermentation and fermentation efficiency was 13.04μg±0.4 of protein/ml/d. The recombinant inulinase was purified and characterized. The molecular weight of the purified recombinant inulinase was 57.6kDa, which was higher than that of the native iunlinase. The optimal pH and temperature of the purified recombinant inulinase were 6.0 and 60°C, respectively. Other biochemical characteristics of the purified recombinant inulinase were the same as those of the native inulinase produced by the marine-derived P. guilliermondii strain 1. The purified recombinant inulinase also had high exoinulinase activity. Therefore, the recombinant inulinase may have highly potential applications in food and pharmaceutical industies. [Copyright &y& Elsevier]

The article presents a study which analyzes the diversity of endophytic yeasts from sweet orange and their localization by sequencing of internal transcribed spacer (ITS) ribosomal ribonucleic acid (rRNA). The plant samples that exhibited different levels of citrus variegated chlorosis (CVC) development were taken from four different sites in São Paulo, Brazil. The three citrus yeasts (CEYs) selected include Rhodotorula mucilaginosa, Cryptococcus flavescens, and Pichia guilliermondii.

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Pichia guilliermondii can produce volatile phenols in the initial stages of wine fermentation; however, its response to different wine stress conditions has been poorly studied. In this work, we present an analysis of the response of 23 P. guilliermondii indigenous isolates to physical and chemical wine stress factors and to indigenous wine killer yeasts. Principal coordinates analysis (PCoA), based on data obtained from response patterns, was carried out to evaluate the relationships among the isolates. Major differences among the isolates were detected in media plates containing 8% ethanol and in those containing 280 g/L glucose. PCoA identified 3 clusters of isolates with different stress response patterns, indicating a relationship between the tolerance to these compounds and the origin of the isolates. Pichia guilliermondii isolates were sensitive to the toxins produced by the species Hanseniaspora uvarum, Metschnikowia pulcherrima, Wickerhamomyces anomala (ex Pichia anomala), and Pichia kluyveri, with a maximum level of sensitivity against W. anomala (91% on average). Those isolates obtained from fermenting must proved to be more resistant to killer yeasts than those obtained from grape surfaces. The combined evaluation of the response to physico-chemical and biological factors presented in this work could be a useful standard protocol for the evaluation of the potential spoilage capacity of yeasts in winemaking. [ABSTRACT FROM AUTHOR]

Two antagonistic yeasts, Candida membranaefaciens and Pichia guilliermondii, were evaluated for the control of the blue mold of apple caused by Penicillium expansum. Dual culture, cell-free metabolite and volatile tests were used for in vitro assay. Yeast strains of two genera inhibited growth of P. expansum; inhibition varied from 30.27% to 44.19% in dual culture, from 79.40% to 90.57% in the volatile metabolite test, and from 72.99% to 88.77% in the cell-free metabolite test. Calcium chloride (2% w/v) significantly inhibited the growth of the pathogen P. expansum, but did not affect the colony-forming units (CFU) of the yeasts C. membranaefaciens and P. guilliermondii in potato dextrose broth. The concentration of yeast suspension influenced spore germination and germ tube growth of P. expansum in vitro, as well as disease incidence and lesion development in fruits. There were significant negative relationships between the suspension concentrations of the yeasts and the growth as well as infectivity of the pathogen. The addition of calcium resulted in lower spore germination rates and slower growth of germ tubes in vitro, as well as in lower disease incidences and smaller lesion diameters compared with treatments with yeast antagonists alone. When yeast cell suspensions reached a concentration of 107 CFU ml-1, growth of the pathogen was completely limited in vitro, and no infection was found in apple fruits treated with or without calcium. [ABSTRACT FROM AUTHOR]

Abstract: The mode of action of an antifungal yeast, Pichia guilliermondii, strain R13, against the fungal pathogen of chilli anthracnose, Colletotrichum capsici, was examined both on agar plates and in chilli fruit wounds. Light microscopy revealed that strain R13 attached to the fungal pathogen, and this attachment apparently restricted the proliferation of C. capsici in the chilli fruit wounds. In chilli juice, strain R13 suppressed C. capsici spore germination and germ tube length, but the suppression was completely overcome by addition of 0.05% glucose, sucrose, or 1% of nitrate sources (NH4NO3, NaNO3, Ca(NO3)2·4H2O, Mg(NO3)2·6H2O, and KNO3), suggesting the yeast was competing with the fungus for these substrates. Strain R13 also produced hydrolytic enzymes, including β-1,3-glucanase, and chitinase, in both solid and liquid media. The activities of these enzymes were highest when the C. capsici hyphal cell walls, rather than laminarin or glucose, were the carbon source; the activities were approximately 2 and 15 times higher with hyphal cell wall than with laminarin or glucose. Unlike the other strains tested, strain R13 did not produce a lethal toxin when cultivated under similar conditions. This study provides evidence that attachment, competition for nutrients, and secretion of hydrolytic enzymes, at least partially, explain how P. guilliermondii strain R13 suppresses C. capsici. [Copyright &y& Elsevier]

Abstract: The yeast Pichia guilliermondii was examined for its ability to control Rhizopus nigricans on tomato fruit during storage, and in order to highlight the reason for biocontrol, a possible mode of action is discussed. Results showed that autoclaved yeast culture and culture filtrate had no effect on controlling the postharvest disease caused by R. nigricans, although inoculation of P. guilliermondii prior to R. nigricans resulted in enhanced biocontrol efficacy. Moreover, rapid colonization of the yeast on wound sites was observed during the initial 3 days at 20°C, and then the population stabilized for the remaining 4 days. This phenomenon indicated that at room temperature, P. guilliermondii could acclimatize itself to the environment of tomato fruit wounds and occupy the living space quickly. The results indicate that P. guilliermondii did not produce an antifungal substance, however, competition for nutrients and space on wounds appeared to play a role in the activity of the biocontrol and could be one of the mechanisms. In addition, the fruit inoculated with P. guilliermondii demonstrated changes in peroxidase (POD), polyphenoloxidase (PPO), superoxide dismutase (SOD), catalase (CAT), phenylalanine ammonia-lyase (PAL), chitinase (CHI) and β-1,3-glucanase activities, all of which were correlated with the onset of induced resistance. This result suggests that tomato fruit is capable of responding to the yeast P. guilliermondii, which could activate defensive enzymes and thereby induce host disease resistance. [Copyright &y& Elsevier]

Abstract: Our overall objectives were to prepare commercially acceptable formulations of the postharvest biological control yeasts, Metschnikowia pulcherrima and Pichia guilliermondii, which have a long storage life and to determine the effectiveness of these formulations to control postharvest green and blue moulds on citrus fruit. Yeasts, grown on a cane molasses-based medium, were combined with talc or kaolin carriers and various adjuvants and the viability of yeast in 12 formulations was determined over a 6 month period. Formulation no. 11, containing talc, sodium alginate, sucrose, and yeast extract, for both yeasts had a significantly higher viable yeast cell content over a 6 month storage period. Among the formulations, three formulations (formulations no. 5, 6, and 11) were selected for additional in vivo testing because they had higher levels of viability amongst yeast cell populations during storage and were easier to resuspend remained in suspension more easily. These formulations were tested on Satsuma mandarin and grapefruit to control green and blue moulds. Formulations no. 5, 6, and 11 for both yeasts effectively controlled green mould, while only formulation no. 11 with either yeast isolate M. pulcherrima (isolate M1/1) or P. guilliermondii (isolate P1/3) effectively controlled both blue and green moulds. [Copyright &y& Elsevier]

Abstract: Yeasts antagonistic to Colletotrichum capsici were isolated from Thai fruits and vegetables. Four antagonists (R13, R6, ER1, and L2) were found that inhibited C. capsici growth with biocontrol efficacies of 93.3%, 83.1%, 76.6%, and 66.4%, respectively. Identification by 26S rDNA, and ITS region sequence together with physiological and morphological characteristics, showed them to be Pichia guilliermondii, Candida musae, Issatchenkia orientalis, and Candida quercitrusa, in order of their efficacy. P. guilliermondii strain R13 showed efficacy in reducing disease incidence on C. capsici infected chilli fruits to as low as 6.5%. Lower disease incidence was observed at lower storage temperature. The application of P. guilliermondii is more effective for preserving chilli fruits than conventional preservation with chlorinated water. [Copyright &y& Elsevier]

Two yeasts, Candida arabinofermentans PYCC 5603T and Pichia guilliermondii PYCC 3012, which show rapid growth onl-arabinose and very high rates ofl-arabinose uptake on screening, were selected for characterization ofl-arabinose transport and the first steps of intracellularl-arabinose metabolism. The kinetics ofl-arabinose uptake revealed at least two transport systems with distinct substrate affinities, specificities, functional mechanisms and regulatory properties. Thel-arabinose catabolic pathway proposed for filamentous fungi also seems to operate in the yeasts studied. The kinetic parameters of the initiall-arabinose-metabolizing enzymes were determined. Reductases were found to be mostly NADPH-dependent, whereas NAD was the preferred cofactor of dehydrogenases. The differences found between the two yeasts agree with the higher efficiency ofl -arabinose metabolism in C. arabinofermentans. This is the first full account of the initial steps ofl-arabinose catabolism in yeast including the biochemical characterization of a specificl -arabinose transporter. [ABSTRACT FROM AUTHOR]

l-Arabinose utilization by the yeasts Candida arabinofermentans PYCC 5603T and Pichia guilliermondii PYCC 3012 was investigated in aerobic batch cultures and compared, under similar conditions, to d-glucose and d-xylose metabolism. At high aeration levels, only biomass was formed from all the three sugars. When oxygen became limited, ethanol was produced from d-glucose, demonstrating a fermentative pathway in these yeasts. However, pentoses were essentially respired and, under oxygen limitation, the respective polyols accumulated—arabitol from l-arabinose and xylitol from d-xylose. Different l-arabinose concentrations and oxygen conditions were tested to better understand l-arabinose metabolism. P. guilliermondii PYCC 3012 excreted considerably more arabitol from l-arabinose (and also xylitol from d-xylose) than C. arabinofermentans PYCC 5603T. In contrast to the latter, P. guilliermondii PYCC 3012 did not produce any traces of ethanol in complex l-arabinose (80 g/l) medium under oxygen-limited conditions. Neither sustained growth nor active metabolism was observed under anaerobiosis. This study demonstrates, for the first time, the oxygen dependence of metabolite and product formation in l-arabinose-assimilating yeasts. [ABSTRACT FROM AUTHOR]