• Korean Journal of Microbiology
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• v.53 no.4
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• pp.235-241
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• 2017

The purpose of this study was to investigate the enhanced physiological activities of two Pichia strains, yeasts isolated from grapes pericarp. Based on phylogenetic analysis using 18S rRNA sequencing, two isolates were identified as Pichia manshurica GU-3 and Pichia terricola GU-4, respectively. The scanning electron microscopic analysis showed that the two isolates grown on YPD medium were of typical elliptical shape with buds and bud scars on cell surface. Physiological activities of the single and mixed Pichia cultures were monitored and compared. In mixed cultures after 72 h of incubation, the maximum activities of tyrosinase inhibition, ACE inhibition, and antioxidant were 81.7%, 45.9%, and 42.7%, respectively. Superoxide dismutase-like activity was approximately 30% in the mixed cultures. These studies demonstrate that Pichia species cultured in the form of mixture can enhance the physiological activities and has potential for the development of new bioactive products.

• Applied Biological Chemistry
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• v.37 no.5
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• pp.315-319
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• 1994

Use of a solid superacid (Nafion) in hydrolysis of rice straw was investigated focusing on the fermentability of the hydrolyzates by Pichia stipitis CBS 5776. Comparisons were made with the hydrolyzates produced by a conventional method of sulfuric acid treatment. The Nafion-catalyzed hydrolyzates of rice straw exhibited low level of inhibition for both cell growth and fermentation in comparison to the hydrolyzates produced by sulfuric acid. Pichia stipitis cells were able to produce ethanol by fermentation of Nafion-catalyzed hydrolyzates when the inoculum level exceeded 3.2 g dry cells/l.

• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.800-808
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• 2003

Three strains of yeasts, Pichia farinosa SKM-1, Pichia anomala SKM-T, and Galactomyces geotrichum SJM-59, produced volatile flavor compounds during fermentation. To investigate these volatile flavor compounds, the liquid culture broth of the three yeast strains were extracted with methylene chloride, and then GC and GC-MS analyses were conducted. Flavor analyses revealed that 5, 12, and 15 kinds of volatile compounds were isolated, and 4, 8, and 11 volatile flavor compounds were identified, respectively. Phenylethyl alcohol was identified with the common volatile flavor compound of Pichia farinosa SKM-1, Pichia anomala SKM-T, and Galactomyces geotrichum SJM-59. 1H-indole-3-ethanol, a precursor of plant growth hormone, was identified from Pichia anomala SKM-T.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.22-28
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• 2004

Livestock industry requires alternatives of antibiotics to prevent environmental pollution and to maintain public health. We herein report on an effective method to reduce ammonia from livestock manure, and confirmed environmentally-friendly livestock production by adding three types of yeast probiotics, Pichia farinosa SKM-1, Pichia anomala SKM-T, and Galactomyces geotrichum SJM-59, into the feed stuff, separately and/or mixed, and these three types of yeasts were administered to the Hy-line brown layers for 8 weeks. Compared with control, the laying performance, the egg quality, and the number of intestinal lactic acid producing bacteria of the treated group were improved and/or increased significantly. Pichia anomala SKM-T potently reduced ammonia production from poultry manure, and the other strains were also able to reduce the ammonia from it. The optimum condition for the reduction of ammonia with Pichia farinosa SKM-1, Pichia anomala SKM-T, and Galactomyces geotrichum SJM-59 was obtained by using the augmented centroid-simplex design. The ratio of optimum condition was Pichia farinosa SKM-1:Pichia anomala SKM-T:Galactomyces geotrichum SJM-59=0.295:0.209:0.080, and the estimate was -123.36 (p=0.0l38). An ability to reduce the ammonia production from livestock manure was maintained at $30^{\circ}C$ for 15 weeks.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.430-438
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• 1996

The eleven strains, which could be used lactic and acetic acids as carbon sources, were isolated from kimchi and identified; the strains were facultative microorganisms which could be grown at low temperature (10$\circ$C) and around pH 3.2. As results of morphological, biochemical and physiological tests, 5 species of 3 genera were identified as Debaryomyces coudertii, Pichia edia, Pichia chambardii, Pichia haplophilia and Saccharomyces fermentati. Each strain was grown in basal media. In acidic resistance and acid utilization test, Saccharomyces sp. YK- 17 and Saccharomyces fermentati YK-19 were grown well in basal and YM media containing 0.3% lactic acid. And two strains were grown in basal and YM media containing O.3% lactic acid and 0.6% acetic acid. Since strain YK-19 was grown better at 10$\circ$C than that in 25$\circ$C, strain YK-19 was known to be a psychrophilic strain.

• Microbiology and Biotechnology Letters
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• v.35 no.3
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• pp.184-190
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• 2007

Approximately 2.0 kb of the promoter region of the Pichia pastoris phosphoglycerate kinase gene (PGK1) was reduced to a 266 bp fragment and this minimized portion was used for construction of a new episomal constitutive expression vector in P. pastoris. As an approach to developing a constitutive expression vector in P. pastoris, the GAP promoter region of the Pichia expression vector pGAPZB was replaced with sequentially deleted PGK1 promoter fragments fused to a beta-galactosidase gene. When a lacZ gene was used as a reporter gene, PGK1 promoter strength was lower than that of the constitutive GAP promoter but it was higher than TEF1. We report here the development of the pPGKZ-E vector as a new episomal expression vector for heterologous gene expression by removing non-essential regions of the PGK1 promoter. This broadens the choice of episomal expression vectors for controlled constitutive expression in P. pastoris.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.493-497
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• 2005

Probiotics are generally excreted within a few days if their ingestion in feces at the same rate as or even more quickly than a transit marker (meaning not clear). Ability of probiotics to adhere to intestine prolongs their persistence in gastrointestinal tract, allowing them to exert healthful effects longer. Hydrophobicities, zeta potentials, Alcian blue-binding capacities, and sedimentation profiles of Pichia farinosa SKM-1, P. anomala SKM-T, and Galactomyces geotrichum SJM-59 were determined to evaluate characteristic properties of cell surfaces responsible for adhesion. Results of intestinal Caco-2 cell line in vitro and murine intestine in vivo studies revealed these strains exhibit adhesive properties regardless of their cell surface hydrophobicity.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.91-95
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• 1992

The hydrolyzates of lignocellulosic biomass contain a mixture of glucose, xylose and cellobiose. The yeast which can produce ethanol efficiently from xylose and cellobiose was selected and its growth and ethanol formation behavior on each sugar and their mixture were investigated. Ethanol yields during batch culture of Pichia stipitis CBS 5776 were 0.4. 0.36 and 0.23 g/g substrate on glucose, xylose and cellobiose, respectively. Mixed sugar fermentation data indicate that glucose causes catabolite regulation on xylose and cellobiose utilization. However, xylose and cellobiose were utilized simultaneously. Ethanol yields on mixtures of sugars were generally additive for each of the substrates.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.966-971
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• 2009

Peroxidase from Coprinus cinereus (CiP) has attracted attention for its high specific activity and broad substrate spectrum compared with other peroxidases. In this study, the functional expression of this peroxidase was successfully achieved in the methylotrophic yeast Pichia pastoris. The expression level of CiP was increased by varying the microbial hosts and the expression promoters. Since a signal sequence, such as the alpha mating factor of Saccharomyces cerevisiae, was placed preceding the cDNA of the CiP coding gene, expressed recombinant CiP (rCiP) was secreted into the culture broth. The Mut Pichia pastoris host showed a 3-fold higher peroxidase activity, as well as 2-fold higher growth rate, compared with the $Mut^s $ Pichia pastoris host. Furthermore, the AOX1 promoter facilitated a 5-fold higher expression of rCiP than did the GAP promoter.

• Microbiology and Biotechnology Letters
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• v.24 no.4
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• pp.512-518
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• 1996

Eleven strains had been previously isolated from kimchi and identified in our laboratory. The ability of each strain in aroma production was investigated by sensory evaluation. Among them Saccharomyc s sp. YK-17, Saccharomyces sp. YK-18, Saccharomyces sp. YH-3 and Saccharomyces fermentati YK-19 produced fruity flavour. Especially, Saccharomyces fermentati YK-19 produced apple and pineapple-like flavours. Pichia media YK-11, Saccharomyces sp. YK-20 and Pichia chambardii YH-4 produced wine-like flavour. Debaryomyces sp. YK-6, Debarymyces coudertii YK-10, Saccharomyces sp. YK-12 and Pichia haplophilia YH-5 produced alcoholic flavours. Using the good flavour producing strains as starters, various groups of kimchi were fermented, and the sensory characteristics of each group such as odor, taste and total acceptability were evaluated. The acidic odor, moldy odor and taste were reduced by adding starter, while the fresh sourness odor and taste similar to fruity fiavour were increased by starter. Comparing with the control group, these odor, taste and total acceptability were increased in the starter-added groups, such as Pichia edia YK-11, Saccharomyces sp. YK-17, and Saccharomyces,fermentati YK- 19. Saccharomyces fermentati YK-19 added kimchi group was higher siginificantly (P<0.05) than the others at the total acceptability. Volatile compounds of the culture broth of Saccharomyces fermentati YK-19 were analysed by gas chromatography, and 6 species of esters and 4 species of alcohols were identified. Among them, the ester substances which broth largely responsible for the apple-like flavour in the sensory evaluation, were found to be ethyl 2-methyl butvrate, ethyl pentanoate and ethyl acetate.