• Korean Journal of Microbiology
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• v.28 no.2
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• pp.174-179
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• 1990

In order to overproduce L-phenylalanine, various kind of regulatory mutants were isolated from parental Escherichia coli K-12. MWEC 83 Producing 7.4g/l of L-phenylalanine has been derived as a tyrosine and tryptophan double auxotrophic mutant. To produce L-phenylalanine without adding L-tyrosine and L-tryptophan, revertant strain MWEC 101 was isolated from MWEC 83. Further various analogues and valine resistant mutants were isolated from MWEC 101. MWEC 101-5 was the most excellent strain that produced 17.9g/l of L-phenylalanine after having been cultivated for 54 hours in 15% glucose medium. It was disclosed that activities of rate-limiting enzymes including chorismate mutase and prephenate dehydratase in MWEC 101-5 were desensitized to 2mM L-phenylalanine in the enzyme reaction mixture and that activities level of 3-deoxy-D-arabino-heptulosonic acid-7-phosphate synthase and prephenate dehydratase were increased more than 20 times over those of the parental strain.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1385-1392
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• 2009

This work evaluates the effect of different amino acids on production of Cyclosporin (CyA) production in solid-state fermentation that was previously optimized for different fermentation parameters by one factor at-a-time for the maximum production of CyA by Tolypocladium inflatum MTCC557. Based on the Plackett-Burman design, glycerol, ammonium sulfate, $FeCl_3$, and inoculum size were selected for further optimization by response surface methodology (RSM). After identifying effective nutrients, RSM was used to develop mathematical model equations, study responses, and establish the optimum concentrations of the key nutrients for higher CyA production. It was observed that supplementation of medium containing (% w/w) glycerol, 1.53; ammonium sulfate, 0.95; $FeCl_3$, 0.18; and inoculum size 6.4 ml/5g yielded a maximum of 7,106 mg/kg as compared with 6,480 mg CyA/kg substrate using one factor at-a-time. In the second step, the effect of amino acids on the production of CyA was studied. Addition of $_L$-valine and $_L$-leucine in combination after 20 h of fermentation resulted in maximum production of 8,166 mg/kg.

• Microbiology and Biotechnology Letters
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• v.20 no.1
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• pp.85-90
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• 1992

Rice bran was employed as a main medium component for ethanol fermentation by Saccharomyces species. Among the several strains of .Saccharomyces yeasts. S. cerevisiae IF0 2346 was selected as the hest strain in view of the interest in the production of ethanol and amino acids. It was found that S. cerevisiae IF0 2346 showed $3\times 10^8$cells/d and 4.7% (v/v) ethanol production after 72 hr cultivation. Although total amount of free amino acids was decreased from 1.099 mg/l to 829 mg/l during the fermentation, glutamic acid. histidine, and isoleucine were increased considerably. With the supplement of 5% glucose to the ferrnentation medium, both ethanol and amino acid production were increased up to 134% and 264%, respectively. compared to the control case. Glutamic. acid, leucine, alanine. phenylalanint:, and valine were the major amino acids in the fermentation broth.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.692-693
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• 2005

• Microbiology and Biotechnology Letters
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• v.5 no.1
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• pp.36-45
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• 1977

A piscicidal substance was isolated from the culture medium of Streptomyces umbrosus by avicel column chromatography and avicel thin layer chromatography after extration with chroloform. Bluegreen fluorescence was emitted under UV irradiation. Factors which govern toxin production and nutrition requirement for high toxin titres were observed. Nutritional uptake for toxin production was not curresponded with that for cell growth. Alanine, valine, serine asparagine, arginine, histidine, urea and sodium nitrate as a carbon source and glucose, mannose, rhamnose, xylose, arabitol and starch as a carbon source were recognized as a favorable nutrient for high toxin production. Magnesium was essential factor whereas vitamins were not of effective. Most of toxin was formed simultaneously with cell growth in esponential phase. Maximal production was observed for six day culture at 3$0^{\circ}C$. Tissues of gill, kidney and pnacreas in Cyprinus carpio were denatured extreamly after treating with the substance. Atrophied nucleous, indented membrane and degradated cytoplasm with necrotic affectness were noted on each tissue. The chemical formula of the substance was designated as $C_{38}$ $H_{66}$ $NO_4$.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1714-1718
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• 2002

Twelve prepubertal Karan Fries heifers (15 months, $167.7{\pm}13.5kg$) were divided into two equal groups. Group 1 was fed as per NRC requirements and group 2 was fed 20% more protein than group 1 heifers. The experimental feeding was continued until the onset of puberty in both the groups. Blood samples were collected at fortnightly intervals and analyzed for amino acids using HPLC. Group 1 and 2 heifers required $178.6{\pm}33.8$ and $152.8{\pm}33.2$ days of experimental feeding to exhibit first estrus resulting in total age at puberty as $639.4{\pm}27.3$ and $618.6{\pm}24.6$ days in the two groups respectively. The concentration of total amino acids averaged 4.40 and 4.89 mmol/l and those of non-essential amino acids (NEAA) was 2.32 and 2.49 mmol/l in groups 1 and 2, respectively. The concentration of plasma essential amino acids i.e. histidine, threonine, valine, methionine, isoleucine, leucine and phenylalanine were higher (p<0.01) in group 2 than group 1. Plasma concentration of large neutral amino acids (LNAA) was significantly higher in group 2 (1.28 mmol/l) than in group 1 (1.12 mmol/l). Increased levels of leucine, isoleucine and valine are implicated in increased follicular growth and development in prepubertal heifers and resulted in a 26 day earlier attainment of puberty by 26 days in an experimental period of six months in group 2 heifers. Increased concentrations of aspartate and tyrosine in group 2 heifers might be associated with the release of GnRH from the hypothalamus influencing LH release from anterior pituitary in such animals. It is therefore evident that increased availability of certain amino acids in heifers fed high protein diet might have led to early onset of puberty.

• Animal Bioscience
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• v.34 no.2
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• pp.295-305
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• 2021

Objective: The objectives of this study were to compare the effects of normal and low protein content (PC) of starter diet supplemented or not with blends of branched-chain amino acids (BCAAs) on growth performance of broilers under summer conditions and to investigate whether these effects altered some quality traits and the characteristics of gastrointestinal tract. Methods: A total of 768 mixed-sex broiler chicks (Ross 308, one-d-old) with an average initial body weight (BW) of 47.6±1.03 g were allocated into six treatments with four replications in 2×3 factorial arrangement. Factors were: PC, normal (N, 22% to d 15); and low (L, 20% to d 15); and added BCAA blends, L-leucine, L-isoleucine, and L-valine at zero (0L:0I:0V); 1.0, 0.25, and 0.25 (4L:1I:1V); or 1.0, 0.25, 0.75 (4L:1I:3V) g/kg of diet. Hence, six dietary treatments were named as N0L:0I:0V, N4L:1I:1V, N4L:1I:3V, L0L:0I:0V, L4L:1I:1V, and L4L:1I:3V. Average indoor temperature and humidity were 32.8℃±1.7℃ and 61.1%±4.12%, respectively. Results: BW, feed conversion ratio (FCR) and carcass weight were not affected by PC, BCCA and their interaction (p>0.05). The L diets decreased the water holding capacity of the breast (p = 0.002) and thigh (p = 0.050) meats and dressing percentage (p = 0.005) compared to the N diets. The 4L:1I:1V diet decreased breast yield compared to the 0L:0I:0V diets (p = 0.041). The effect of PC on feed intake, mortality and gastrointestinal trait weight were depended on the L:I:V ratios under summer conditions due to interactions between factors (p<0.05). The FI and mortality of L4L:1I:1V broilers were lower than those of N4L:1I:1V birds (p<0.05). Conclusion: It was concluded that the blends of BCAAs used failed to improve performance and to promote breast yields, because diets with normal or with reduced protein supplemented or not with BCAAs up to d 15 produced a similar BW and FCR in broilers raised in hot-climate conditions.

• Korean journal of food and cookery science
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• v.26 no.4
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• pp.422-427
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• 2010

This study was conducted to investigate the antioxidant effect and properties of unfermented tea and fermented tea made with Rhodotorula yeast. The levels of crude fat and crude protein in the fermented tea were higher than those in the unfermented tea. The water-soluble phenol levels of unfermented tea and fermented tea were 912.5 and 2,445.24 ppm, respectively. The total amino acid content of fermented tea was greater than that of unfermented tea;,- the amino acid concentrations of alanine, valine, leucine, and lysine were 25.58, 24.38, 27.96, and 14.14 ${\mu}g/mL$, respectively. The DPPH radical scavenging activities of the unfermented and fermented teas were 32.14 and 41.57%, respectively; this is in contrast to 29.73% for L-ascorbic acid(150 ppm). The reducing power activity of fermented tea was 41.57%, and that of unfermented tea was 32.14%.

• Asian-Australasian Journal of Animal Sciences
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• v.33 no.1
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• pp.79-90
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• 2020

Objective: In the present study, an liquid chromatography/mass spectrometry (LC/MS) metabolomics approach was performed to investigate potential biomarkers of milk production in high- and low-milk-yield dairy cows and to establish correlations among rumen fluid metabolites. Methods: Sixteen lactating dairy cows with similar parity and days in milk were divided into high-yield (HY) and low-yield (LY) groups based on milk yield. On day 21, rumen fluid metabolites were quantified applying LC/MS. Results: The principal component analysis and orthogonal correction partial least squares discriminant analysis showed significantly separated clusters of the ruminal metabolite profiles of HY and LY groups. Compared with HY group, a total of 24 ruminal metabolites were significantly greater in LY group, such as 3-hydroxyanthranilic acid, carboxylic acids, carboxylic acid derivatives (L-isoleucine, L-valine, L-tyrosine, etc.), diazines (uracil, thymine, cytosine), and palmitic acid, while the concentrations of 30 metabolites were dramatically decreased in LY group compared to HY group, included gentisic acid, caprylic acid, and myristic acid. The metabolite enrichment analysis indicated that protein digestion and absorption, ABC transporters and unsaturated fatty acid biosynthesis were significantly different between the two groups. Correlation analysis between the ruminal microbiome and metabolites revealed that certain typical metabolites were exceedingly associated with definite ruminal bacteria; Firmicutes, Actinobacteria, and Synergistetes phyla were highly correlated with most metabolites. Conclusion: These findings revealed that the ruminal metabolite profiles were significantly different between HY and LY groups, and these results may provide novel insights to evaluate biomarkers for a better feed digestion and may reveal the potential mechanism underlying the difference in milk yield in dairy cows.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.320-328
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• 2021

High GABA-enriched yeast extract, for various nutritionally and pharmaceutically important functional foods, was prepared using a novel isolate of Debaryomyces hansenii JBCC541. Under optimized conditions, GABA conversion rates are significantly enhanced up to 7.55 g/l by D. hansenii JBCC541, increasing their synthesis yield 40 times. The total amino acid content of the prepared yeast extract was 10733.86 mg/l (257.36 mg/g), consisting of alanine, lysine, glutamine, leucine, and valine as the primary amino acids. The GABA content was significantly enhanced up to 6790 mg/l (162.80 mg/g) in the presence of glutamic acid, with approximately 10-fold higher GABA production. Flavor amino acids were also highly enhanced, indicating that the prepared yeast extract might be useful for preparing various functional and sensuous foods. Our results were promising as a GABA-enriched yeast extract preparation tool ensuring a suitable food material level with the potential for functionally enhanced food industrial applications.