• 한국미생물·생명공학회지
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• 제18권6호
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• pp.578-584
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• 1990

토양시료로부터 CGTase를 생산하는 중성의 호열성 미생물을 conogo red가 포함된 배지를 이용하여 분리하고, 분리균주의 형태학적, 생리학적 성질을 조사한 결과 Bacillus stearothermophilus No.239로 동정되었다. 초기 pH가 7.0인 soluble starch 2, defatted soybean meal 0.5, NaH_2PO_4.2H_2O$ 0.1및 $CaCl_2$ 0.01%5를 지닌 배지 에서$55^{\circ}C$, 48시간 진탕 배양하였을 때 배양액 1ml당 약 7.0unit로 가장 높은 효소생산량을 보였다.

• Asian-Australasian Journal of Animal Sciences
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• 제30권2호
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• pp.171-180
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• 2017

Objective: This study investigated the association of enzyme-producing microbes and their enzymes with starch and hemicellulose degradation during fermentation of total mixed ration (TMR) silage. Methods: The TMRs were prepared with soybean curd residue, alfalfa hay (ATMR) or Leymus chinensis hay (LTMR), corn meal, soybean meal, vitamin-mineral supplements, and salt at a ratio of 25:40:30:4:0.5:0.5 on a dry matter basis. Laboratory-scale bag silos were randomly opened after 1, 3, 7, 14, 28, and 56 days of ensiling and subjected to analyses of fermentation quality, carbohydrates loss, microbial amylase and hemicellulase activities, succession of dominant amylolytic or hemicellulolytic microbes, and their microbial and enzymatic properties. Results: Both ATMR and LTMR silages were well preserved, with low pH and high lactic acid concentrations. In addition to the substantial loss of water soluble carbohydrates, loss of starch and hemicellulose was also observed in both TMR silages with prolonged ensiling. The microbial amylase activity remained detectable throughout the ensiling in both TMR silages, whereas the microbial hemicellulase activity progressively decreased until it was inactive at day 14 post-ensiling in both TMR silages. During the early stage of fermentation, the main amylase-producing microbes were Bacillus amyloliquefaciens (B. amyloliquefaciens), B. cereus, B. licheniformis, and B. subtilis in ATMR silage and B. flexus, B. licheniformis, and Paenibacillus xylanexedens (P. xylanexedens) in LTMR silage, whereas Enterococcus faecium was closely associated with starch hydrolysis at the later stage of fermentation in both TMR silages. B. amyloliquefaciens, B. licheniformis, and B. subtilis and B. licheniformis, B. pumilus, and P. xylanexedens were the main source of microbial hemicellulase during the early stage of fermentation in ATMR and LTMR silages, respectively. Conclusion: The microbial amylase contributes to starch hydrolysis during the ensiling process in both TMR silages, whereas the microbial hemicellulase participates in the hemicellulose degradation only at the early stage of ensiling.

• Asian-Australasian Journal of Animal Sciences
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• 제28권1호
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• pp.50-57
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• 2015

This study was conducted to investigate the effect of soybean meal (SM) and soluble starch (SS) on biogenic amine production and microbial diversity using in vitro ruminal fermentation. Treatments comprised of incubation of 2 g of mixture (expressed as 10 parts) containing different ratios of SM to SS as: 0:0, 10:0, 7:3, 5:5, 3:7, or 0:10. In vitro ruminal fermentation parameters were determined at 0, 12, 24, and 48 h of incubation while the biogenic amine and microbial diversity were determined at 48 h of incubation. Treatment with highest proportion of SM had higher (p<0.05) gas production than those with higher proportions of SS. Samples with higher proportion of SS resulted in lower pH than those with higher proportion of SM after 48 h of incubation. The largest change in $NH_3$-N concentration from 0 to 48 h was observed on all SM while the smallest was observed on exclusive SS. Similarly, exclusive SS had the lowest $NH_3$-N concentration among all groups after 24 h of incubation. Increasing methane ($CH_4$) concentrations were observed with time, and $CH_4$ concentrations were higher (p<0.05) with greater proportions of SM than SS. Balanced proportion of SM and SS had the highest (p<0.05) total volatile fatty acid (TVFA) while propionate was found highest in higher proportion of SS. Moreover, biogenic amine (BA) was higher (p<0.05) in samples containing greater proportions of SM. Histamines, amine index and total amines were highest in exclusive SM followed in sequence mixtures with increasing proportion of SS (and lowered proportion of SM) at 48 h of incubation. Nine dominant bands were identified by denaturing gradient gel electrophoresis (DGGE) and their identity ranged from 87% to 100% which were mostly isolated from rumen and feces. Bands R2 (uncultured bacterium clone RB-5E1) and R4 (uncultured rumen bacterium clone L7A_C10) bands were found in samples with higher proportions of SM while R3 (uncultured Firmicutes bacterium clone NI_52), R7 (Selenomonas sp. MCB2), R8 (Selenomonas ruminantium gene) and R9 (Selenomonas ruminantium strain LongY6) were found in samples with higher proportions of SS. Different feed ratios affect rumen fermentation in terms of pH, $NH_3$-N, $CH_4$, BA, volatile fatty acid and other metabolite concentrations and microbial diversity. Balanced protein and carbohydrate ratios are needed for rumen fermentation.

• KSBB Journal
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• 제24권1호
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• pp.30-40
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• 2009

Aspergillus terreus에 의한 이타콘산 생산 발효공정에서 생산균주의 성장을 어느 정도 제한시킴으로써 배양생리적 특성이 이타콘산 생합성 쪽으로 치우치도록 통계적 방법을 적용하여 itaconic acid의 생산배지 조성을 최적화하는 연구를 수행하였다. 이타콘산은 TCA회로를 거쳐 합성된 cis-aconitic acid의 디카르복실화 반응에 의해 생합성되는 고부가 화학원료물질이다. 우선 One factor at a time (OFAT) 방법을 이용하여 이타콘산의 생산성 증가에 크게 영향을 미치는 중요한 탄소원들로 sucrose, glucose, fructose와 soluble starch를 확인할 수 있었고, 질소원들로는 cottonseed flour와 soybean meal을 찾을 수 있었다. Fractional factorial design을 통하여 이들 6가지 요인들 간의 상호작용의 정도를 확인한 결과 sucrose와 cottonseed flour간의 상호작용의 정도가 가장 컸고, 나머지 요인들 간의 상호작용의 정도는 작거나 혹은 이타콘산 생산에 오히려 부정적인 결과를 나타냈다. 또한 full factorial design (FFD) 실험을 통해 생산배지에 $KH_2PO_4$와 $MgSO_4$가 과량 첨가되면 이타콘산의 생산성이 심각하게 저해됨을 알 수 있었다. FFD의 1차모델식을 근간으로 하여 최급상승법 (steepest ascent method, SAM)을 적용하여 sucrose, cottonseed flour, $KH_2PO_4$ 및 $MgSO_4$의 최적 농도로 향하는 가장 가파른 기울기를 구함으로써, 신속하고 효율적으로 최적 농도지점에 대한 정보를 얻을 수 있었다. SAM이 제시해주는 농도 부근에서 반응표면분석 (response surface method, RSM)을 적용하여 각 배지성분의 농도를 최적화시키기 위해, 2개의 중요한 요인인 sucrose와 cottonseed flour를 이용하여 중심합성계획 (central composite design, CCD) 실험을 수행하였다. 그 결과 이타콘산의 최적 배지 조건은 sucrose 90.4 g/L, cottonseed flour 53.8 g/L인 것으로 관찰되었고, 이 농도에서 이타콘산의 생산성은 초기 사용된 배지에서의 생산성에 비해 약 7배 증가한 4360 mg/l로 나타났다. 이로부터 탄소원 (C)으로 사용한 sucrose와 질소원 (N)으로 사용한 cottonseed flour 간의 C/N 비율이 이타콘산의 생산성에 큰 영향을 미친다는 것을 확인할수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• 제26권12호
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• pp.1732-1741
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• 2013

Two experiments were conducted to determine physical and chemical properties of vermicelli waste (VW) and effect of VW inclusion levels on growth performance of broilers. In experiment 1, VW samples were randomly collected from vermicelli industry in Thailand to analyze nutritional composition. Vermicelli waste contained 9.96% moisture, 12.06% CP, 32.30% crude fiber (CF), and 0.57% ether extract (EE), as DM basis. The ratio of insoluble:soluble non-starch polysaccharide (NSP) was 43.4:8.9. A total of 120 chicks (6 pens per treatment and 10 chicks per pen) were fed a corn-soybean meal-based diet or 20% VW substituted diet to determine the apparent metabolizable energy corrected for nitrogen retention ($AME_n$) of VW. The $AME_n$ of VW was $1,844.7{\pm}130.71$ kcal/kg. In experiment 2, a total of 1,200 chicks were randomly allotted to 1 of 4 dietary treatments for 42-d growth assay. There were 300 chicks with 6 pens per treatment and 50 chicks per pen. The dietary treatments contained 0%, 5%, 10%, or 15% VW, respectively. All diets were formulated to be isocaloric and isonitrogenous. From 0 to 18 d of age chicks fed VW diets had higher (p<0.001) feed conversion ratio (FCR) compared with those fed the control diet. No difference was observed during grower and finisher phase (19 to 42 d). Chicks fed VW diets had lower relative weight of abdominal fat (p<0.001) but higher relative weight of gizzard (p<0.05) than those of chicks fed the control diet. Increasing VW inclusion levels increased ileal digesta viscosity (p<0.05) and intestinal villus height of chicks (p<0.001). For apparent total tract digestibility assay, there were 4 metabolic cages of 6 chicks that were fed experimental treatment diets (the same as in the growth assay) in a 10-d total excreta collection. Increasing VW inclusion levels linearly decreased (p<0.05) apparent total tract digestibility of DM and CF.