• Journal of Microbiology and Biotechnology
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• v.12 no.1
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• pp.162-165
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• 2002

With the objective of identifying the commercial potential of new direct-fed microbials, several temperature-tolerant strains were isolated from cane molasses at $39^{\circ}C$ and tested for their tolerance to pH, bile salts, and a mixture of volatile fatty acids (acetic acid:propionic acid:butyric acid=6.5:2.0:1.5). It was found that the isolated strain DY 252 grew very well up to pH 2.0 and was resistant to relatively high concentrations of bile salts. Among the strains tested, DY 252 was least inhibited by the addition of volatile fatty acids to the growth medium at $39^{\circ}C$. Accordingly, it would appear that strain DY 252, identified as yeast Issatchenkia orientalis, may be a potential candidate for use as a microbial feed additive.

• Journal of Aquaculture
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• v.9 no.4
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• pp.329-337
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• 1996

Dietary values of phytoplanktons, concentrated Chlorella and commercial yeasts were investigated for the resting egg production of the Korean rotifer, B. plioatilis S-type. The hatching rate of the resting egg of the rotifer fed on different diets was also studied. The highest production of the resting egg was 3,760 eggs/20 ml with N. oculata. However, the hatching rate was not significant among 4 phytoplankton species. The highest production of resting eggs among 9 diet groups ($\omega$-yeast, baker's yeast, 2 refrigerated Marine Chlorella, frozen Marine Chlorella, frozen Chlorella ($70\%$) + baker's yeast ($30\%$), frozen Chlorella ($30\%$) + baker's yeast ($70\%$), 2 refrigerated freshwater Chiorella) was 283 eggs/ml in the frozen Chlorella ($30\%$) +baker's yeast ($70\%$) and the refrigerated freshwater Chlorella. The highest number of resting egg from 10,000 rotifers and 1 mg dry wieght diet was 5,566 eggs and 2,131 eggs in the frozen Chlorella ($30\%$) + baker's yeast ($70\%$). However, the highest hatching rate of the resting eggs was $67.4\%$ in $\omega$-yeast. In this study, the results suggest that the baker's yeast with a small amount of frozen Chlorella seems to be good feeding regime for the economical production of resting eggs.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.308-311
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• 2005

Electron beam irradiation was applied to examine microbial safety and qualities of black pepper powder and commercial Sunsik. Whole black pepper powder and commercial Sunsik were irradiated at 2, 4, 8, 12, and 16 kGy. Microorganism contamination in black pepper powder and commercial Sunsik were significantly decreased by irradiation. Decimal reduction doses ($D_{10}\;value$) of total bacteria count in black pepper powder and commercial Sunsik were 5.32 and 1.56 kGy, respectively. $D_{10}\;value$ of yeast and mold were 2.54 and 2.14 kGy for black pepper powder and commercial Sunsik, respectively. Electron beam irradiation caused negligible changes in Hunter color L, a, and b values. Sensory evaluations of black pepper powder and commercial Sunsik showed no significant changes among samples. These results indicate electron beam irradiation improves microbial safety and qualities of black pepper powder and commercial Sunsik.

• Korean Journal of Food Science and Technology
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• v.28 no.2
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• pp.253-259
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• 1996

To investigate the yeast florae in the traditional and commercial Kochujang, computer identification systems, Vitek, API kit and conventional identification methods were used. Yeast florae of each process were compared and their typical physiological characteristics were also tested. Various process intervals yielded 330 colonies, which resulted in 11 species 184 strains classified. They were identified into Candida glabrata C. guilliermondii. C. humicola. C. rugosa, C. zeylanoides, Cryptococcus uniguttulatus, Pichia farinosa, Rhodotorula glutinis, Saccharomyces cerevisiae and Zygosaccharomyces rouxii. The strains of Candida, Pichia, Saccharomyces and Zygosaccharomyces were existing in both processes. In case of commercial process, the maximum distribution of Z. rouxii and S. cerevisiae were 33% at 15 day fermentation and 13% at 21 day, respectively. The distribution of Candida spp. was gradually decreased throughtout the fermentation period from 40% to 10%. In the traditional process, the maximum distribution of Z. rouxii and S. cerevisiae were 53% after 3 months and 26% after 7 months, respectively, S. cerevisiae and Z. rouxii showed distintive growth pattern at the high concentration of glucose and sodium chloride and played important roles in both processes of fermentation. Physiological tests revealed that only two major yeasts. S. cerevisiae and Z. rouxii, showed vigorous carbon dioxide formation under the tested conditions.

• Journal of Aquaculture
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• v.10 no.1
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• pp.87-95
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• 1997

This experiment was conducted for compare domestic experimental microparticulated diets with imported commercial microparticulated diets in olive flounder larvae, Paralichthys olivaceus (Temminck et Schlegel). Fish larve were fed four microparticulated diets from 8th day after hatching. Four diets were two commercial microparticulated diets D and H, and experimental microparticulated diets K1 and K2 formulated each with different protein sources (diet K1 ; squid meal, blood meal, yeast extract, chlorella powder, olive flounder muscle, Lys, and Met ; diet K2 ; whole egg protein, krill meal, short-necked clam meal, squid muscle, live yeast, yeast extract, and casein). There were no significant differences on body weight, body length and survival rates among four diet treatments up to the 40th day after hatching. At the 83th day after hatching, fish fed diet D had a significantly higher survival rate than that of fish fed diet K2, whereas there was no significant difference between to diet H and K1. Fish fed diet D had a significantly higher body weight than these of fish fed diaet K1 and K2, whereas there was no significant difference between fish fed diet D and H. There was no significant difference on EPA and DHA of body fatty acid composition among four diet treatments up to the 83th day after hatching. These results show that nutritionally well-ballanced domestic microparticulated diets for olive flouner lavae can be developed.

• The Korean Journal of Mycology
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• v.39 no.1
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• pp.78-84
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• 2011

To develop new functional traditional rice wines using Gugija and Liriope tuber as raw materials, screenings of optimal fungal nuruk and alcohol fermentative yeast for brewing of Gugija-L. tuber traditional rice wine were performed with investigation of optimal fermentation condition. Finally, we selected commercial SJ nuruk and Saccharomyces cerevisiae C-2 as optimal nuruk and yeast for Gugija-L. tuber traditional rice wine. Furthermore, a new antihypertensive and anti-gout Gugija-L. tuber traditional rice wine was produced when 3% of Jangmyong Gugija and L. tuber No.1 were added into cooked rice and then fermented at $25^{\circ}C$ for 5 days with SJ nuruk and S. cerevisiae C-2.

• Journal of Animal Science and Technology
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• v.63 no.3
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• pp.563-574
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• 2021

A total of 1512 Ross 308 broilers (one - day - old) were assigned (random blocks) to 1of 3 dietary treatments with 28 replicates of 18 chicks/cage. The dietary treatments were Cornsoybean-meal based basal diet supplemented with 0%, 0.1%, and 0.2% of commercial yeast hydrolysate (YH [Saccharomyces cerevisiae]). The graded level of YH supplementation has linearly increased broilers body weight gain on d 21, 35, and overall (p = 0.044, 0.029, and 0.036, respectively) experimental period. In addition, the increased level of YH supplementation has linearly reduced feed conversation ratio of broilers on d 21, 35, and overall trial period (p = 0.041, 0.052, and 0.032, respectively). However, the feed intake and mortality of broilers were not affected by the graded level of YH supplementation. Though nutrient digestibility of dry matter (p = 0.012) and nitrogen (p = 0.021) was linearly increased in broilers fed YH supplementation, at the end of the trial it fails to affect the total track digestible energy. Dietary inclusion of YH supplementation showed a beneficial effect on the microbial population as linearly improved lactobacillus (p = 0.011) and reduced Escherichia coli counts (p = 0.042). An increasing level of YH supplementation has tended to decrease NH₃ (p = 0.069) and linearly decrease H₂S (p = 0.027) of noxious gas emission in broilers. Moreover, dietary YH supplements trend to increase the glucose (p = 0.066) and reduced cholesterol (p = 0.069) level. At the end of the test, YH supplementation elicited a linear reduction in drip loss on days 5 and 7, respectively (p = 0.045, and 0.021). Furthermore, dietary inclusion of YH supplementation had linearly increased villus height (p = 0.051) but fails to affect crypt depth. Therefore, in terms of positive effects on the broiler's overall performance, we suggest that dietary supplements containing graded YH levels in the broilers diet could serve as a potential alternative for growth promoters.

• Journal of Microbiology and Biotechnology
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• v.33 no.11
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• pp.1531-1541
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• 2023

Lipase is a well-known and highly in-demand enzyme. During the last decade, several lipase optimization studies have been reported. However, production costs have always been a bottleneck for commercial-scale microbial enzyme production. This research aimed to optimize the conditions for lipase production by Limtongozyma siamensis DMKU-WBL1-3 via a One-Factor-At-a-Time (OFAT) approach combined with statistical methods while using a low-cost substrate. Results suggest that low-cost substrates can be substituted for all media components. An optimal medium was found, using response surface methodology (RSM) and central composite design (CCD), to consist of 0.50% (w/v) sweet whey, 0.40% (w/v) yeast extract (food grade), and 2.50% (v/v) palm oil with the medium pH adjusted to 4 under shaking flask cultivation. From an economic point of view, this work was successful in reducing production costs while increasing lipase productivity. The medium costs were reduced by 87.5% of the original cost while lipase activity was increased by nearly 6-fold. Moreover, lipase production was further studied in a 2-L stirred-tank fermentor. Its activity was 1,055.6 ± 0.0 U/ml when aeration and agitation rates were adjusted to 1 vvm and 170 rpm, respectively. Interestingly, under this optimal lipase production, the yeast showed accumulated lipids inside the cells. The primary fatty acid is a monounsaturated fatty acid (MUFA) that is typically linked to health benefits. This study hence reveals promising lipase production and lipid accumulation by L. siamensis DMKU-WBL1-3 that are worthy of further study.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.4
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• pp.401-408
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• 1985

The yeast cell wall lytic action of the alkaline AL-protease, which was found out of the crude Zymolyase that a kind of yeast cell wall lytic $endo-{\beta}-1$, 3-glucanase produced from Arthrobacter luteus, was investigated with the viable cells of S. sake and it's cell wall preparation. AL-protease on the lysis of the viable yeast cells showed very low activities with the alone, but the lytic activities were highly increased with the combination of AL-protease and Zymolyase. On the stepwise treatment of the viable yeast cells with AL-protease and Zymolyase, the cells were lysed highly only by the course having a treatment with Zymolyase after pretreatment with AL-protease. Thus synergistic action of AL-protease was not observed with any some commercial enzymes, known as a type of alkaline and serine protease such as AL-protease, and was also found to be affected greatly by the culture conditions and species of the yeast tested. AL-protease caused the release of some peptide and a lot of sugar from the cell wall preparation, but could not lysed the cell wall more than 66%. Whereas Zymolyase could lysed the cell walls almost completely with alone. On the basis of these results, the synergistic action of AL-protease on the lysis of S. sake cells is hypothesized that at first AL-protease bind to the yeast cell surface layer consisting of mannan and protein, and then changes their conformation to facilitate the penetration of Zymolyase from the outside to the inside framework layer constituted of alkali insoluble ${\beta}-1,\;3-glucan$.

• Journal of Applied Biological Chemistry
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• v.54 no.4
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• pp.252-257
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• 2011

To remove excess nitrate from the agricultural environments, Enterobacter amnigenus GG0461 has been isolated as a bacterial strain having high capability of nitrate uptake activity. This strain was able to remove nitrate more than 3,000 ppm (50 mM) in the Pseudomonas agar F (PAF) medium. Therefore, it could be a candidate strain for a nitrate scavenger in the various contaminated environments, such as agricultural soils, livestock sewage, and industrial wastewater. In order to develop medium for the large-scale production of the strain GG0461, each component of PAF medium was replaced with the corresponding commercial product and the optimal conditions for bacterial growth and nitrate uptake activity were measured. Glycerol was replaced with the commercially available product and the nitrogen source was substituted with commercial tryptone, yeast extract, soybean meal, and fermented fish extract. Bacterial growth and nitrate uptake activity were maximal in the media containing 2% tryptone, followed by yeast extract, soybean meal, and fermented fish extract. The pH of the growth medium containing 2% tryptone was decreased by the bacterial nitrate uptake, suggesting that the nitrate uptake is mediated by a nitrate/proton antiporter. This result shows that the medium containing commercial tryptone was good enough for the physiological activity of the strain GG0461. Each component of PAF medium was successfully replaced with the corresponding commercial product except peptone. In conclusion, the composition of medium for the cultivation of the strain GG0461 was determined as 2% tryptone, 1% glycerol, plus required salts according to the composition of PAF medium.