• Asian-Australasian Journal of Animal Sciences
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• 제24권5호
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• pp.650-654
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• 2011

An experiment involving 180 straight run one-day-Cobb broilers was conducted to evaluate the effect of supplementation of L-leucine with different levels of crude protein (CP) on carcass composition and sensory characteristics of broiler grower-finisher chickens. Six experimental diets comprising two levels of crude protein (CP) i.e., 20 and 20% with three levels of L-leucine i.e. 0, 0.5 and 0.67%, were offered to birds from 21-42 d of age. The birds were randomly divided into 36 experimental pens, 5 chickens in each pen, and there were 6 replicates under each diet. L-leucine supplementation did not affect the bone and lean, whereas fat was decreased (p<0.05) when L-leucine was added at 0.5%. Similarly, there were no significant differences (p>0.05) in the lean, fat and bone among chickens fed two levels of CP. No significant differences between dietary treatments were observed on any sensory characteristics affected by dietary L-leucine and CP. From this study, it is obvious that supplementation of up to 0.5% L-leucine reduced fat. However, other characteristics were not affected by supplementation of L-leucine. Similarly, reduction of body composition and sensory characteristics were not apparent on a diet low in CP.

• 한국미생물·생명공학회지
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• 제26권1호
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• pp.45-49
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• 1998

Corynebacterium glutamicum ATCC13032를 모균주로 한 아미노산 유사체들에 저항성을 지닌 돌연변이 균주들로부터 두 종류의 L-로이신 생산균주를 개발하였다. 그 중 하나인 C. glutamicum LT26은 4-azaleucine과 $\alpha$-amino-$eta$-hydroxyvaleric acid에 저항성을 지니는 균주이며, 다른 한 균주는 C. glutamicum LT3811-70로서 C. glutamicum LT26을 모균주로한 DL-4-tiaisoleucine 저항성 돌연변이 균주이다. 이들 두 돌연변이 균주들의 배양액내에서의 L-로이신의 축적은 이들이 비영양요구성 균주임에도 불구하고 모균주보다 획기적으로 높았으며 이를 해명하고자 L-이소로이신과 L-발린 그리고 L-로이신 생합성 과정의 주반응 효소인 $\alpha$-acetohydroxy acid synthase(AHAS)와 $\alpha$-isopropylmalate synthase(IPMS)의 분석을 수행하였다. C. glutamicum LT26과 LT3811-70에서 AHAS와 IPMS는 모두 L-로이신에 대해 효소활성저해와 효소합성저해가 거의 해제되었고, C. glutamicum LT3811-70 균주의 경우 모균주인 C. glutamicum LT26 균주보다 IPMS의 L-로이신에 대해 효소 합성저해가, AHAS는 L-이소로이신과 L-발린등에 대해 효소활성저해가 10% 이상 더 해제되었음을 알 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권4호
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• pp.523-528
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• 2013

This study investigates the effects of three branched-chain amino acids (BCAA; valine, leucine, and isoleucine) on the in vitro ruminal fermentation of wheat straw using batch cultures of mixed ruminal microorganisms. BCAA were added to the buffered ruminal fluid at a concentration of 0, 2, 4, 7, or 10 mmol/L. After 72 h of anaerobic incubation, pH, volatile fatty acids (VFA), and ammonia nitrogen ($NH_3$-N) in the ruminal fluid were determined. Dry matter (DM) and neutral detergent fiber (NDF) degradability were calculated after determining the DM and NDF in the original material and in the residue after incubation. The addition of valine, leucine, or isoleucine increased the total VFA yields ($p{\leq}0.001$). However, the total VFA yields did not increase with the increase of BCAA supplement level. Total branched-chain VFA yields linearly increased as the supplemental amount of BCAA increased (p<0.001). The molar proportions of acetate and propionate decreased, whereas that of butyrate increased with the addition of valine and isoleucine (p<0.05). Moreover, the proportions of propionate and butyrate decreased (p<0.01) with the addition of leucine. Meanwhile, the molar proportions of isobutyrate were increased and linearly decreased (p<0.001) by valine and leucine, respectively. The addition of leucine or isoleucine resulted in a linear (p<0.001) increase in the molar proportions of isovalerate. The degradability of NDF achieved the maximum when valine or isoleucine was added at 2 mmol/L. The results suggest that low concentrations of BCAA (2 mmol/L) allow more efficient regulation of ruminal fermentation in vitro, as indicated by higher VFA yield and NDF degradability. Therefore, the optimum initial dose of BCAA for in vitro ruminal fermentation is 2 mmol/L.

• 한국미생물·생명공학회지
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• 제20권6호
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• pp.677-680
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• 1992

Corynebacterium glutamicum CH 1516(L-leucine 생산주)를 사용하여 7l 발효조에서 배양온도 및 pH, 산소전달속도 등을 최적화한 결과 각각 $30^{\circ}C$, 7.0, 0.21 kmole $O_2$/$m^3{\cdot}hr$이었다. 산소전달속도가 0.19 kmole $O_2$/$m^3{\cdot}hr$ 보다 낮은 조건에서는 상당량의 lactic acid가 축적되었고 0.23 kmole $O_2$/$m^3{\cdot}hr$보다 높은조건에서는 glutamic acid가 생성되고 PCV가 크게 증가하였다. 한편 1200l 실험공장에서의 L-leucine 생산을 위해 7l 발효조에서 최적화된 배양조건을 적용하여 산소전달속도를 지표로 공정확대를 실시한 결과 7l 발효조와 거의 대등한 결과를 얻을 수 있었으며,산화한 원전위 -15-170 mV에서 L-leucine이 왕성하게 생산되었다.

• 한국미생물·생명공학회지
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• 제10권3호
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• pp.177-184
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• 1982

토양에서 분리, 선별한 Streptomyces 속의 한 균주가 생산하는 Penicillinase의 최적생산조건을 조사한 결과를 요약하면 다음과 같다. 탄소원으로서는 glucose, 실소원으로는 L-as-paragine이 가장 우수했으며 금속감중에서 Mn C $l_2$를 첨가했을때 효소생성을 37% 증가시켰다. Amino 산중에서 L-leucine이 본 효소생산을 약간 증가시켰으며 L-histidine L-methionine은 크게 저하시켰다. Riboflavine, i-inositol, hesperidine, niacinamide, biotin, DL-$\alpha$- lipoic acid, folic acid가 효소생산을 증가시켰으며 항생물질중에서 cephradine, cephalexin, ampicillin, cloxacillin의 첨가가 효소생성을 크게 증가시켰다. 본 효소생산의 최고 pH는 7.0이며 최적온도는 28$^{\circ}C$였다. 또 500$m\ell$ Erlenmeyer flask에서 175$m\ell$의 배지를 가하여 3 일간 배양했을 때 효소생성이 최고에 도달했다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권6호
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• pp.842-848
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• 2019

Objective: Heat stress poses an increasing threat for poultry production. Some amino acids have been found to play critical roles in affording thermotolerance. Recently, it was found that in ovo administration of L-leucine (L-Leu) altered amino acid metabolism and afforded thermotolerance in heat-exposed broiler chicks. Methods: In this study, two doses (35 and $70{\mu}mol/egg$) of L-Leu were administered in ovo on embryonic day 7 to determine their effect on rectal temperature (RT), body weight (BW) and thyroid hormones at hatching. Changes in RT, BW, and thermotolerance in post-hatched chicks were also analyzed. Results: It was found that in ovo administration of L-Leu dose-dependently reduced RT and plasma thyroxine ($T_4$) level just after hatching. In post-hatched neonatal broiler chicks, however, the higher dose of L-Leu administered in ovo significantly increased RT without affecting BW gain. In chicks that had been exposed to heat stress, the RT was significantly lowered by in ovo administration of L-Leu (high dose) in comparison with the control chicks under the same high ambient temperature (HT: $35^{\circ}C{\pm}1^{\circ}C$, 120 min). Conclusion: In ovo administration of L-Leu in a high dose contributed to an increased daily body temperature and afforded thermotolerance under HT in neonatal broiler chicks.

• Journal of Microbiology and Biotechnology
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• 제28권11호
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• pp.1916-1927
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• 2018

Corynebacterium glutamicum is an excellent platform for the production of amino acids, and is widely used in the fermentation industry. Most industrial strains are traditionally obtained by repeated processes of random mutation and selection, but the genotype of these strains is often unclear owing to the absence of genomic information. As such, it is difficult to improve the growth and amino acid production of these strains via metabolic engineering. In this study, we generated a complete genome map of an industrial L-valine-producing strain, C. glutamicum XV. In order to establish the relationship between genotypes and physiological characteristics, a comparative genomic analysis was performed to explore the core genome, structural variations, and gene mutations referring to an industrial L-leucine-producing strain, C. glutamicum CP, and the widely used C. glutamicum ATCC 13032. The results indicate that a 36,349 bp repeat sequence in the CP genome contained an additional copy each of lrp and brnFE genes, which benefited the export of L-leucine. However, in XV, the kgd and panB genes were disrupted by nucleotide insertion, which increase the availability of precursors to synthesize L-valine. Moreover, the specific amino acid substitutions in key enzymes increased their activities. Additionally, a novel strategy is proposed to remodel central carbon metabolism and reduce pyruvate consumption without having a negative impact on cell growth by introducing the CP-derived mutant $H^+$/citrate symporter. These results further our understanding regarding the metabolic networks in these strains and help to elucidate the influence of different genotypes on these processes.

• Journal of Microbiology and Biotechnology
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• 제20권7호
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• pp.1086-1091
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• 2010

This study explored the use of gellan gum as an immobilization matrix for the production of cyclosporin A (CyA) by immobilized spores and mycelia of Tolypocladium inflatum MTCC 557. Different carriers, such as gellan gum, sodium alginate, celite beads, and silica, were tested as immobilization carriers, along with the role of the carrier concentration, biomass weight, number of spore-inoculated beads, and repeated utilization of the immobilized fungus. The maximum CyA production was 274 mg/l when using gellan gum [1% (w/v)], and a mycelial weight of 7.5% (w/v) supported the maximum production of CyA. Additionally, the addition of a combination of $_L$-valine (6 g/l) and $_L$-leucine (5 g/l) after 48 h of fermentation produced 1,338 mg/l of CyA when using gellan gum. The immobilized mycelia beads were found to remain stable for four repetitive cycles, indicating their potential for semicontinuous CyA production.

• 한국미생물·생명공학회지
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• 제19권1호
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• pp.76-81
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• 1991

2l 발효조에서 pH6.9, 온도 $32^{\circ}C$일 때 당밀배지를 이용하여 Corynebacterium glutamicum의 영양요구성 유사체 내성변이주에 의한 라이신 발효시 산화환원 전위 (ORP)가 라이신 발효속도의 특성에 미치는 영향을 조사하였다. 희석률이 0.1$h ^1$일때 탄소원이 제한되건 로이신이 제한되건 산소가 제한되지 않는 한 최대의 대당수율 24를 보였으며, 이 때의 산화환원 전윈 값은 -60mV와 -100mV 범위에 해당하였다. 산화화원 전위 값이 -130mV의 매우 낮은 용존산소 조건하에서는 대당수율 밀 $q_s, q_p$ 등의 발효 반응속도 상수값들이 크게 감소하였으며 glvcine, alanine, valine을 포함하는 발효 부산물의 축적량이 매우 높아졌다.

• Journal of Microbiology and Biotechnology
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• 제19권11호
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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.