• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.570-583
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• 2021

Pyrococcus furiosus α-amylase can hydrolyze α-1,4 linkages in starch and related carbohydrates under hyperthermophilic condition (~ 100℃), showing great potential in a wide range of industrial applications, while its relatively low productivity from heterologous hosts has limited the industrial applications. Bacillus subtilis, a gram-positive bacterium, has been widely used in industrial production for its non-pathogenic and powerful secretory characteristics. This study was conducted to increase production of P. furiosus α-amylase in B. subtilis through three strategies. Initial experiments showed that co-expression of P. furiosus molecular chaperone peptidyl-prolyl cis-trans isomerase through genomic integration mode, using a CRISPR/Cas9 system, increased soluble amylase production. Therefore, considering that native P. furiosus α-amylase is produced within a hyperthermophilic environment and is highly thermostable, heat treatment of intact culture at 90℃ for 15 min was performed, thereby greatly increasing soluble amylase production. After optimization of the culture conditions (nitrogen source, carbon source, metal ion, temperature and pH), experiments in a 3-L fermenter yielded a soluble activity of 3,806.7 U/ml, which was 3.3- and 28.2-fold those of a control without heat treatment (1,155.1 U/ml) and an empty expression vector control (135.1 U/ml), respectively. This represents the highest P. furiosus α-amylase production reported to date and should promote innovation in the starch liquefaction process and related industrial productions. Meanwhile, heat treatment, which may promote folding of aggregated P. furiosus α-amylase into a soluble, active form through the transfer of kinetic energy, may be of general benefit when producing proteins from thermophilic archaea.

• KSBB Journal
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• v.9 no.4
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• pp.418-427
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• 1994

For the production of ${\alpha}$-amylase cloned from Bacillus licheniformis expressed in E. coli, cultivating factors including the concentrations of glucose, maltose and acetic acid were investigated. The results were as follows: 1) Maximum ${\alpha}$-amylase yield and maximum specific production rate obtained from glucose source were better than those achieved from maltose source. 2) The optimum production yield of ${\alpha}$-amylase was obtained at 1.0ml/$\ell$ or less of initial acetic acid concentration.

• Microbiology and Biotechnology Letters
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• v.18 no.3
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• pp.309-316
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• 1990

The sequence of a 1795 bp restriction fragment containing the B. circulans F-2 gene for NaC1- dependent $\alpha$-amylase (CI-amylase) is reported. The probable coding region of the gene is 1005 base pairs (335 amino acida) long. The NaC1-dependent $\alpha$-amylase (el-amy) sequence shows an open reading frame (ORF) with the translated molecular weight of about 38, 006, which correspond to a molecular weight of about 35, 000 (Mi). The gene is preceded by the sequence resembling promoter for the vegetative B, subtitis RNA polymerases. These are followed by the sequences resembling a B. subtilis ribosome binding site 5 nucleotides before the first codon of the gene. Homologous regions with other amylases were found. The N-terminal sequences of the mature proteins expressed in E. eoli were identical to the N-terminal sequences which are anaIysed.

• Microbiology and Biotechnology Letters
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• v.9 no.2
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• pp.91-97
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• 1981

A thermophilic soil isolate Bacillus sp. Y-127 was selected for the production of thermostable amylase. The strain was used for the enzyme production and the thermostable amylase was characterized. The optimum cultural conditions for the enzyme production were 6$0^{\circ}C$ at pH 7.0 for 32 hours using a mineral medium containing 2% soluble starch and 0.2% yeast extract. The extra-cellular enzyme was purified about 123-folds with about 6% recovery. The purified enzyme was stable at pH between 4.0 and 7.0, and temperature up to 6$0^{\circ}C$.

• Korean Journal of Microbiology
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• v.15 no.1
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• pp.31-41
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• 1977

Dextrinogenic and glucoamylase activities of Aspergillus isolated from various habitat-substrates collected through South Korea are measured, and their amylase activities are surveyed in taxonomical and ecological viewpoints. 1. A. flavous group and A.wentii group exhibited higher activities for both amylases than others. 2. In the relations between amylase activity of Asperguillus and their habitat-sub-strates, the strains isolated from meju and cereals exhibited predominant dextrinogenic amylase activity. 3. Dextrinogenic amylase activity of Aspergillus is higher in the strains isolated from southern coast than the other regions. 4. Among the 601 strains of Aspergillus surveryed, strain No.74 and strain No.421 exhibited the most predominant activity for dextrinogenic amylase and glucoamylase, respectively.

• Journal of Environmental Science International
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• v.16 no.4
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• pp.409-414
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• 2007

Effects of dimethipin on ${\alpha}$-amylase activity of barley seeds were investigated. In the treatments of $1{\mu}M\;and\;10{\mu}M$ dimethipin, the indexes of germination were reduced to 17% and 24 % respectively. After seed germination, dimethipin was added to germinated seedlings and then the seedlings were kept to measure seedling length under illumination for 7 days. In control, the length of seedling was 5.7 cm, but in the treatments of $1{\mu}M$ dimethipin and $10{\mu}M$ dimethipin, seedling lengths were 5.5 cm and 1.2 cm respectively. In the relationship between dimethipin concentrations and ${\alpha}$-amylase activities, there was a linear curve. The more dimethipin was added to the seeds, the more ${\alpha}$-amylase activities were inhibited. In the treatments of $1{\mu}M$ dimethipin and $10{\mu}M$ dimethipin, ${\alpha}$-amylase activities were reduced to 33% and 71% respectively. Dimethipin also inhibited ${\alpha}$-amylase activities increased by gibberellin and the content of soluble protein. Therefore, it could be suggested that dimethipin might inhibit directly the activities of hydrolysis enzymes including ${\alpha}$-amylase or the expression of ${\alpha}$-amylase genes as germination and seedling growth were severely disturbed.

• Microbiology and Biotechnology Letters
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• v.14 no.3
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• pp.209-212
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• 1986

$\alpha$-Amylase gene of Bacillus amyloliquetaciens was cloned on plasmid YEp13, S. cerevisiae-E. coli shuttle vector. Hybrid plasmid pTG17, carrying $\alpha$-amylase gene of B. amyloliquefaciens, was transformed to E. coli and the expression of it in yeast was investigated. This plasmid was unstable in E. coli and produced two minor plasmids, pTG17-1 and PTG17-2, which resulted from the segregation of it. Transformant of S. cerevisiae MC16 with pTG17-1 plasmid was not appeared on SD medium because of the Leu2 gene defection. S. cerevisiae could be transformed by the hybrid plasmid, and $\alpha$-amylase activity of the yeast transformant was detected by somogyi-Nelson method and agar diffusion method.

• Asian Journal of Turfgrass Science
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• v.1 no.1
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• pp.49-55
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• 1987

Zoysia japonica를 부위별로 나누어서 그들간의 amylase와 nitrate reductase의 활성을 조사한 결과는 다음과 같다. 1. Amylase의 활성은 관부에서 8.36~9.46 unit/mg.rotein/hr.로 가장 높았고 이삭에서 2.04 unit/mg.rotein/hr.로 가장 낮았다. 포복경, 뿌리, 잎에서의 amylase의 활성을 각각 5.42~5.82, 3.76, 2.32~3.16 unit/mg.rotein/hr.나타내었다. 2. Nirate reductase의 활성은 빛을 많이 받는 잎에서 0.35~0.66 n mole/mg.rotein/hr.로 가장 높았고 관부에서 0.06~0.10 n mole/mg.rotein/hr.로 가장 낮았다. 이삭과 포복경에서는 각각 0.31,0.27~0.63 n mole/mg.rotein/hr.를 나타내었다. 이러한 결과로부터 저장기관인 관부나 관부 절간에서 높은 amylase의 활성을 이용하여, 양분을 이삭으로 이동시키고 있음을 알 수 있었다. nitrate reductase의 활성은 chloroplast를 갖지 않는 기관보다 광합성기관에서 더 높았다. 잔디밭에서 같이 사는 크로버와 비교해 보면 amylase의 활성이 Zoysia japonica보다 2배가량 더 높았다. 이러한 결과로부터 잔디밭에서 크로버가 더 생장력이 큼을 알 수 있었다.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.12
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• pp.1749-1754
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• 2006

Two slaughter experiments were conducted to determine the effects of rumen escape starch, by altering dietary starch concentration and corn particle size, on ${\alpha}$-amylase activity in the pancreas and the small intestinal digesta of lambs. In experiment 1, 18 wether lambs (28.5${\pm}$1.6 kg) were fed low, medium or high starch diets for 35 d and slaughtered. Dietary starch concentrations linearly increased rumen escape starch (p<0.05). Pancreatic ${\alpha}$-amylase activity was lower (p<0.05) in lambs fed the low starch diet. When expressed per gram of digesta, ${\alpha}$-amylase activity was lower in lambs fed the low starch diet. However, expressed as total activity, ${\alpha}$-amylase in the digesta was greater in lambs fed the medium starch diet. In experiment 2, 12 wether lambs (23.5${\pm}$0.3 kg) were fed diets with finely cracked corn, coarsely cracked corn and whole corn. These dietary treatments continued for 35 d before tissue collection. Rumen escape starch increased with increasing corn particle size (p<0.05). ${\alpha}$-amylase activity in the pancreas and the small intestinal digesta was significantly greater (p<0.05) in lambs fed the coarsely cracked corn. These data suggest that increasing rumen escape starch results in a quadratic increase in total ${\alpha}$-amylase activity in the pancreas and the small intestinal digesta. Maximum ${\alpha}$-amylase activity is reached when rumen escape starch is about 100-120 g/d in 25-30 kg lambs.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.123-127
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• 1969

The studies were conducted to know the relationship between $\beta$-amlyase activities and hardiness for the germinated seedlings of, winter wheat varieties which were classified with eye estimated cold resistance in field as, susceptible, moderate and resistant. These varieties were tested in continued five days from germination in four replicated split plot design. For the measurement of $\beta$-amylase, improved A. K. Balls method (2) was employed. Result obtained will be summarized as follows. 1. Tested varieties showed highly significant differences in $\beta$-amylase activity, while no differences were obtained between dates after germination. 2. Winter hardy varieties, Yukseung ＃3, Chin Kwang and Suwon＃85 showed higher amylase activities than the moderate hardy varieties, Jukdalma, Kangdosinryuk and Norin ＃4, while lower activities were measured in susceptible varieties, Norin ＃6, Kangdo and Norin＃12. 3. With measurement of $\beta$-amylase activity, rurther detail classification to cold resistance is seemed available than eye-estimating in the field condition. 4. In accordance with testing dates, amylase activities were not so clear on 1st, 2nd, 4th and 5th days from germination, while clear differences were found on 3rd day from germination. 5. Amylase activity obtained on 3rd day after germination is considered easy and effective method to estimate cold resistance of wheat varieties with a classification standard.