• Journal of Microbiology and Biotechnology
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• 제24권10호
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• pp.1368-1376
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• 2014

This article focuses on the effects of glycine betaine on preventing caramelization, and increasing DCW and $\small{L}$-lysine production. The additional glycine betaine not only decreased the browning intensity (decreased 4 times), and the concentrations of 5-hydroxymethylfurfural (decreased 7.8 times) and furfural (decreased 12 times), but also increased the availability of glucose (increased 17.5%) for $\small{L}$-lysine production. The DCW and $\small{L}$-lysine production were increased by adding no more than 20 mM glycine betaine, whereas the DCW and $\small{L}$-lysine production were decreased with the reduction of pH values, although pH had a better response to prevent caramelization than did glycine betaine. For $\small{L}$-lysine production, the highest increase (40%) was observed on the media with 20 mM glycine betaine. The crucial enzymes in glycolysis and $\small{L}$-lysine biosynthesis pathway were investigated. The results indicated that additional glycine betaine increases the activity of enzymes in glycolysis, in contrast to the effect of pH. All the results indicated that glycine betaine can be used to prevent caramelization and increase the $\small{L}$-lysine production. By applying this strategy, glucose would not be have to be separated from the culture media during autoclaving so that factories can save production costs and shorten the fermentation period.

• 한국미생물·생명공학회지
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• 제26권5호
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• pp.400-405
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• 1998

본 연구는 B. lactofermentum에서 ddh유전자의 증폭이 lysine 생성량에 미치는 영향을 조사하기 위하여, 먼저 E. coli-B. lactofermentum shuttle vector pEB1 및 pEB2를 제조하였으며, 제조된 shuttle vector에 ddh 유전자를 ligation하여 재조합 plasmid pRK1 및 pRK2를 구축하였다. B. lactofermentum에서 ddh 유전자를 증폭시키기 위하여 재조합 plasmld를 B. lactofermentum으로 도입하여 DDH 활성을 측정한 결과 대조균보다 7배 정도 증가하였다. 또한 lysine 생성량의 비교 분석에서는 재조합 plasmid를 함유한 균주의 경우 48시간 이후부터 control 균주보다 lysine 생성량이 증가하기 시작하여 72시간 때에는 최대치를 나타내었으며 그 이후는 오히려 감소하였다. 최대치를 나타낸 72시간 때의 lysine 생성량은 대조균주가 4.30∼4.38 g/l를 나타내었으며 pRK1 및 pRK2를 함유한 균주는 각각 5.34 g/l 및 5.07 g/l이었다. 이상의 결과로 미루어 볼 때 ddh유전자의 증폭에 의한 B. lactofermentum의 lysine 생성량은 대조균주에 비하여 18∼20% 정도 증가하였다.

• 한국식품과학회지
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• 제31권1호
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• pp.224-230
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• 1999

$_L-Lysine$ 발효산업에 이용되고 있는 B. lactofermentum의 L-lysine 생합성은 succinylase 경로와 dehydrogenase 경로를 통하여 일어난다. 특히 lysine 생산 균주에 부가적으로 존재하는 dehydrogenase 경로는 lysine 생합성에 있어서 필수적인 경로로 작용하며 이때 meso-DAP-dehydrogenase (DDH)를 암호화하는 ddh gene이 관여한다. 그러므로 B. lactofermentum의 lysine 발효에 있어서 ddh gene의 over expression에 의한 lysine 생성량을 비교 조사하기 위하여, shuttle vector pEB1 및 pJC1으로 ddh gene을 삽입하여 재조합 plasmid pRK1 및 pRK31을 구축하였고 이를 B. lactofermentum으로 도입시켜 DDH 활성을 측정한 결과 pRK1을 함유한 균주는 대조균주보다 7배 정도, pRK31을 함유한 균주는 14배 정도 증가하였다. 또한 Shuttle vector를 함유한 대조균주와 재조합 plasmid를 함유한 균주간의 성장 비교에서는 서로 비슷한 수준을 나타내었으며 플라스크 배양에서 lysine 생성량의 비교 분석에서는 재조합 plasmid를 함유한 균주의 경우 48시간 이후부터 대조균주보다 lysine 생성량이 증가하기 시작하여 72시간때에는 최대치를 나타내었으며 그 이후는 오히려 감소하였다. 최대치를 나타낸 72시간 때의 lysine 생성량은 대조균주가 4.38g/L를 나타내었으며 pRK1 및 pRK31을 함유한 균주는 각각 5.34g/L 및 5.21 g/L이었다. 이상의 결과로 미루어 볼 때 B. lactofermentum내에서 ddh gene의 증폭에 의한 lysine 생성량은 pRK1 및 pRK31에서 대조균주보다 각각 20% 및 19% 증가하였다. 또한 발효조 배양에서의 lysine 생성량도 재조합 균주가 대조균주보다 23% 정도 증가를 나타내어 B. lactofermentum에서 ddh gene의 증폭으로 lysine 생성량이 증가하였음을 확인하였다.

• 한국산업융합학회 논문집
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• 제2권1호
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• pp.77-83
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• 1999

Grown in the secondary broth of production media, the strain Streptomyces albulus has increased more the production of its metabolite ${\varepsilon}$-poly-L-lysine, one of poly(amino acid)s used as disinfecting food additives, than the strain in the primary culture of growth nutrients. Having the strain removed, the large concentrate obtained by ultrafiltrating the secondary culture broth. The concentrated production broth exchanged into followed by detecting in UV flowcell at 220nm the peptide bond of the components eluting the adsorbed proteins and polylysine with NaCl salt of gradient concentration, and has separated into five components. Among them the component in the fourth peak fraction has proved to be the pure ${\varepsilon}$-poly-L-lysine after the portion being hydrolyzed the fraction with HCl into amino acid followed by being the composing amino acid analysis.

• 한국미생물·생명공학회지
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• 제24권3호
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• pp.376-379
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• 1996

Cane molasses, the most widely used carbon source for the industrial fermentation of L-lysine, usually contains a high concentration of calcium ions which tend to cause scaling problem in the recovery process. To remove the calcium ions, cane molasses was pretrea ted with sulfuric acid by adjusting the pH to 2.5-3.5. When the pretreated solution was directly heat-sterilized and used in the fermentation, a significant reduction in L-lysine production was observed. In this paper, we proved that sucrose is a superior substrate for L-lysine fermentation to that of glucose or fructose and that the above-mentioned decrease of L-lysine production was caused by the hydrolysis of sucrose in the molasses when the molasses was heat-sterilized at a low pH. The problem was overcome by adjusting the pH of molasses to neutral before sterilization.

• KSBB Journal
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• 제16권5호
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• pp.474-479
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• 2001

$_{L}$-Iysine 의 생산을 Corynebacterium glutamicum SH35을 이용하여 유가식 배양법과 연속 배양법으로 수행하였다. 유가시 배양에 의한 $_{L}$-Iysine 생산을 조사한 결과 최종 발효액 중의 lysine 농도는 129.2 g/L, lysine 수율 및 productivity는 가각 47%m 3.08g.$L^{-1}$.$h^{-1}$이였다. Single-stage 연속 배양에서 dilution rate에 따른 균의 생장 및 lysine 생산을 조사한 결과, critical diluation rate은 0.100 h$^{-1}$으로 이때 균체농동($OD_{610}$)은 67, lysine 농도는 44.0 g/L 그리고 lysine 수율 및 productivity 는 41%, 4.39 g.$L^{-1}$.$h^{-1}$이고 lysine 연속배양 시 최적의 dilution rate 이였다. 또한 lysine 생산을 위한 medium reservoir 내의 최적 탄소원 농도, 최적 질소원(ammonium sulfate) 농도 및 최적 pH는 각각 108 g/L, 25 g/L 및 6.9이었다. 유가식 배양법과 single-state 연속 배양법에 의한 lysine 생산에서, productivity 는 유가식 배양의 경우 3.08 g.$L^{-1}$.$h^{-1}$인 반면, 연속 배양에서는 4.39 g.$L^{-1}$.$h^{-1}$로 유가식 배양법에서보다 약 1.4배 정도 증가하였따. 연속 발효 공정을 통해 생산 역가의 향상은 있었으나, lysine 농도와 수율이 낮아 이에 대한 해결책으로 two-stage 연속 배양 방법을 수행하였다. 그 결과, 연속 배양 발효 수행보다 lysine 농도는 2배 정도 증가하였으며, lysine 수율은 46%로서 유가식 배양과 비슷한 정도로 얻어졌다. 이러한 실험 결과로 미루어 lysine 생산 역가 향상을 위한 방법으로 two-stage 연속배양의 산업적인 이용가능성이 있을 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제21권1호
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• pp.90-96
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• 2008

We compared the effects of supplementing $L-lysine{\cdot}SO_4$ to L-lysine HCl on growth performance, nutrient digestibility and nitrogen retention in weaning pigs. A total of 96 crossbred pigs, weaned at $21{\pm}3$ days of age and with an average initial body weight (BW) $6.23{\pm}0.01kg$, were given one of 4 treatments, which translated into 6 replicates of 4 pigs in each pen. The animals were randomly assigned to four dietary treatments according to a randomized completely block design (RCBD) as follows: 1) control-no synthetic lysine, lysine deficient (0.80% total lysine); 2) L-C (= 0.2% L-lysine HCl); 3) K-L-S (= 0.332% $L-lysine{\cdot}SO_4$, A company); 4) C-L-S (= 0.332% $L-lysine{\cdot}SO_4$, B company). Diets were formulated with corn, soy bean meal, and corn gluten meal as the major ingredients, and all nutrients except the lysine met or exceeded NRC requirements (1998). The lysine content of supplemented synthetic lysine was the same in all treatment groups except the control. No clinical health problems associated with the dietary treatments were observed. During the entire experimental period, body weight, average daily gain (ADG) and feed efficiency (G:F ratio) increased (p<0.01) in pigs fed the experimental diets supplemented with L-lysine??HCl or $L-lysine{\cdot}SO_4$ produced by A company, irrespective of the two synthetic lysine sources. Although the supplementation of $L-lysine{\cdot}SO_4$ produced by B company tended to improve the ADG and G:F ratio, significant differences were not seen among all treatments and tended to be lower than the L-C (L-lysine HCl) and K-L-S ($L-lysine{\cdot}SO_4$ groups using the product from A company). The digestibility of crude protein (CP) was increased by the supplementation of synthetic lysine (p<0.05), irrespective of the L-lysine source (L-C, K-L-S, C-L-S). The results of this study showed that ADG, G:F ratio, and CP digestibility improved when $L-lysine{\cdot}SO_4$ or L-lysine HCl was supplemented into the weaning pigs' diet. There was a clear difference in efficacy between the two $lysine{\cdot}SO_4$ products based upon the growth performance of weaning pigs. Consequently, the bioavailability of $lysine{\cdot}SO_4$ products should be evaluated before supplementation of synthetic lysine in swine diets.

• Asian-Australasian Journal of Animal Sciences
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• 제20권10호
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• pp.1580-1586
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• 2007

The objective of this study was to compare the bioefficacy of L-lysine sulfate relative to L-lysine${\cdot}$HCl for 10 to 20 kg pigs. Two experiments were conducted to determine the bioefficacy of the two sources of lysine using daily gain, feed conversion, plasma urea nitrogen and nitrogen retention as the response criteria. In experiment 1, 168 crossbred barrows ($Landrace{\times}Large$ White), weaned at $28{\pm}3$ d ($9.07{\pm}0.78$kg body weight), were allotted to one of seven dietary treatments in a $2{\times}3$ (two lysine $sources{\times}three $ lysine levels) factorial arrangement of treatments with an added negative control treatment group. The basal diet was based on corn, peanut meal and soybean meal and provided 0.67% lysine. The basal diet was supplemented with 0.1, 0.2 or 0.3% lysine equivalents supplied from either L-lysine sulfate or L-lysine${\cdot}$HCl. Each treatment was fed to six pens of pigs with four pigs per pen. The trial lasted 21 days. The relative bioefficacy value of lysine in L-lysine sulfate using daily gain, feed conversion and plasma urea nitrogen as response criteria was 1.01, 1.05 and 1.04 of the lysine in L-lysine${\cdot}$HCl, respectively. In experiment 2, 42 crossbred ($Landrace{\times}Large$ White) pigs ($16.03{\pm}1.58$ kg body weight) were housed in stainless steel metabolism cages for 10 d and fed the seven diets used in the nitrogen-balance trial. The relative bioefficacy value of L-lysine sulfate was estimated to be 0.95 as effective as L-lysine${\cdot}$HCl for nitrogen retention on an equimolar basis. The t-test analysis revealed that bioefficacy of lysine in L-lysine sulfate was not significantly different from lysine in L-lysine${\cdot}$HCl, which was set at 1.00. In conclusion, L-lysine sulfate can be used instead of L-lysine${\cdot}$HCl to fortify lysine-deficient diets fed to 10 to 20 kg pigs.

• Asian-Australasian Journal of Animal Sciences
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• 제22권5호
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• pp.721-726
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• 2009

The molecular mechanism of adipocyte differentiation has been well documented. However, the effect of specific nutrients such as lysine on adipocyte differentiation is poorly understood especially in ruminant animals. Therefore, the aim of the present study was to elucidate the influence of lysine on adipocyte differentiation and adipogenic genes in cultured bovine preadipocytes. The preadipocytes were treated with different concentrations of lysine (40, 160, 320 mg/L) or troglitazone (10 ${\mu}M$) for 2 days and then subsequently cultured in differentiation medium until day 6. Expression levels of $C/EBP{\alpha}$ were significantly higher (p<0.001) in 40 and 160 mg/L lysine-treated cells compared to 320 mg/L treatment. Though there was an increasing trend in $PPAR{\gamma}$ expression levels with the decreasing lysine concentration, the results were not significant. The preadipocyte factor (pref-1), expression significantly (p<0.001) reduced with decreasing lysine concentration. The Oil red O staining results were better in 40 mg/L treated cells compared to 160 and 320 mg/L lysine treated cells. Our overall results indicate that insufficient supply of lysine increases the adipogenic potential in bovine intramuscular preadipocytes.

• Journal of Microbiology and Biotechnology
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• 제25권3호
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• pp.358-365
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• 2015

ε-Poly-L-lysine (ε-PL) is a homopolymer of L-lysine molecules connected between the epsilon amino and alpha carboxyl groups. This polymer is currently used as a natural preservative in food. Insufficient biomass is a major problem in ε-PL fermentation. Here, to improve cell growth and ε-PL productivity, various nitrogen-rich nutrients were supplemented into flask cultures after 16 h cultivation, marking the onset of ε-PL biosynthesis. Yeast extract, soybean powder, corn powder, and beef extract significantly improved cell growth. In terms of ε-PL productivity, yeast extract at 0.5% (w/v) gave the maximum yield (2.24 g/l), 115.4% higher than the control (1.04 g/l), followed by soybean powder (1.86 g/l) at 1% (w/v) and corn powder (1.72 g/l) at 1% (w/v). However, supplementation with beef extract inhibited ε-PL production. The optimal time for supplementation for all nutrients examined was at 16 h cultivation. The kinetics of yeast-extract-supplemented cultures showed enhanced cell growth and production duration. Thus, the most commonly used two-stage pH control fed-batch fermentation method was modified by omitting the pH 5.0-controlled period, and coupling the procedure with nutrient feeding in the pH 3.9-controlled phase. Using this process, by continuously feeding 0.5 g/h of yeast extract, soybean powder, or corn powder into cultures in a 30 L fermenter, the final ε-PL titer reached 28.2 g/l, 23.7 g/l, and 21.4 g/l, respectively, 91.8%, 61.2%, and 45.6% higher than that of the control (14.7 g/l). This describes a promising option for the mass production of ε-PL.