Isolation and identification of Bacillus megaterium producing Alkaline α-amylase

Shiru Jia,Yong-Deok Choe,Hoon Cho 대한환경위생공학회 2008 대한환경위생공학회지 Vol.23 No.1

A bacterial strain, Bacillus megaterium L-49 has been isolated and identified that produces alkaline a-amylase. The cell is ellipsoidal, about 1.0-1.2 × 3.0-3.6 ㎛ in diameter, Gram-positive, motile, and central partial central. Growth occurs in media containing 7% of NaCl. This strain could utilize D-glucose, lactose, xylose, sucrose, mannose, and maltose, and but it does not utilize D-fructose, and glycogen. Among the various concentrations of saturated ammonium sulfate, the retractation ratio in range of 70 to 100% was about 93%. However, in the case of acetone, it was about 98.7%. EDTA has activating effect and Ca2+ has no effect on alkaline α-amylase activity. The alkaline a-amylase has low thermal stability. The optimal temperature for reaction is 50℃The alkaline a-amylase activity maintained stabilizing at pH 6-11 and the optimal pH for reaction was 9-10.

Characteristics and Model for Growth of Rhizopus oryzae on the Simulated Gas-solid Interface

( Shiru Jia ),( Ri Xiang Kong ),( Hui Jun Dong ),( Kyu Hyuk Kwun ),( Sun Il Kim ),( Ki An Cho ),( Du Bok Choi ) 한국환경생물학회 2004 환경생물 : 환경생물학회지 Vol.22 No.4

N/A In order to investigate the effect on morphology of Rhizopus oryzae and production of lactic acid, various interface materials were used. Morphology of fungal showed sheet and flock when resin was added. The production of lactic acid was increased dramatically when interface materials were added. Furthermore, the effect of resin was more significant than that of others. It was assumed that interface materials could absorb substrate and microorganism together, so microorganism was not inhibited by substrate. The effect of static electric field on the interface culture was studied. When the exerting potential was 6.78 voltage, the biomass y was obviously higher than that of zero voltage. A simulated gas-solid interface system was developed to study the growth and two phases model for the growth of Rhizopus oryzae was build up that depended on the symmetric branching theory. An important parameter F was researched. The results indicated that the value of F had obvious difference at exponential and deceleration period, respectively.

Characterization of Extracellular Polysaccharides from Nostoc flagelliforme Cells in Liquid Suspension Culture

Shiru Jia,Haifeng Yu,Yongxian Lin,Yujie Dai 한국생물공학회 2007 Biotechnology and Bioprocess Engineering Vol.12 No.3

Nostoc flagelliforme cells were studied with regard to the physico-chemical characterization of the extracellular polysaccharides (EPS) secreted in a liquid suspension culture. The hydrolyzed EPS were determined to be composed of four neutral sugars, which were glucose (43.2%), xylose (20.6%), galactose (29.9%), and mannose (6.3%). The glucuronic acid was the only uronic acid identified in the residue. The apparent molecular weight was estimated at 2.79 × 105. The Fourier transform infrared spectra showed that the EPS evidenced characteristics typical of non-sulfated polysaccharides. The UV spectrum and Bradford reaction indicated that there were no nucleic acids and proteins in them. The thermal analysis showed a decomposition peak at 245oC on the thermogravimetric (TG) curves. The scanning electron microscope (SEM) analysis indicated that the EPS possessed a porous structure. The observed microstructural irregularities indicated that the polysaccharide was a type of amorphous solid. These results showed that the EPS of N. flagelliforme cells might be employed as a substitute for those normally derived from field colonies. The results of this study may prove to be beneficial to the protection of the natural resource represented by N. flagelliforme.

Alkaline α-amylaseProduction from Bacillus megaterium

Shiru Jia,Chae-kyu Lim,Gwang-yeob Seo,Hyung-Gun Nam 대한환경위생공학회 2009 대한환경위생공학회지 Vol.24 No.1

The enzyme expressed from strain L-49 was 2.01 times higher than that of original strain. Strain L-49 can grow on culture plate with 50㎍/mL ampicillin. The synthesis of α-amylase was greatly suppressed when strain L-49 was grown on monosaccharide such as glucose and polysaccharide at the same time cell concentration was low. Amylase production was enhanced when the bacterium was grown on starch and dextrin. Among different nitrogen sources tried, yeast extract was found to be the best followed by panpeptone, peptone, meat extract, bean meal, and corn steep liquor. The average rate of enzyme production was enhanced for 3~4 times in fermentation time from 24h to 44h.. The sugar uptake rate has also increased. Low oxygen supply rate enhanced the rate of strain propagation but depressed the enzyme production. Hence it is benefit to obtain high enzyme activity that agitation speed maintained not lower than 400r/min and aeration rate maintained greater than 1:1vvm.

Fractionation and Characterization of ε-Poly-L-lysine from Streptomyces albulus CGMCC 1986

Shiru Jia,Yujie Dai,Baoqing Fan,Guoliang Wang,Yuanyuan Jia,Peng Peng 한국식품과학회 2010 Food Science and Biotechnology Vol.19 No.2

ε-Poly-L-lysine (ε-PLL) produced by Streptomyces albulus CGMCC 1986 was fractionated using ultra-filtration technique with 2 and 5 kDa cut-offs of membrane. The number-average molecular weight of each fraction was determined by 1H nuclear magnetic resonance (NMR)method. The number-average molecular weights of the cutoffs of 5 and 2 kDa and the filtrate are 4,230.95, 3,687.80,and 1,900.82 Da, respectively. 1H NMR indicates the chemical shifts of α-H, β-H, γ-H, δ-H, and ε-H are very similar to all the fractions. Fourier transform-infrared (FTIR)spectra showed that the ε-PLL solid samples obtained by freeze-drying at pH 5 with molecular weights higher than 2 kDa take on a β-turn conformation, however, the fraction with molecular weight smaller than 2 kDa adopts random coil structure. The antibacterial test proved that the fraction between 2 and 5 kDa of membranes behaves the highest antibacterial activity than other fractions for the test strains of Staphylococcus aureus, Micrococcus luteus,Bacillus subtilis, Escherichia coli, and Shigella.

Characteristics and model for growth of Rhizopus oryzae on the simulated gas-solid interface

shiru Jia,김선일,권규혁,조기안,Rixiang Kong,Huijun Dong,최두복 한국환경생물학회 2004 환경생물 : 환경생물학회지 Vol.22 No.4

In order to investigate the effect on morphology of Rhizopus oryzae and production of lactic acid, various interface materials were used. Morphology of fungal showed sheet and flock when resin was added. The production of lactic acid was increased dramatically when interface materials were added. Furthermore, the effect of resin was more significant than that of others. It was assumed that interface materials could absorb substrate and microorganism together, so microorganism was not inhibited by substrate. The effect of static electric field on the interface culture was studied. When the exerting potential was 6.78 voltage, the biomass y was obviously higher than that of zero voltage. A simulated gas-solid interface system was developed to study the growth and two phases model for the growth of Rhizopus oryzae was build up that depended on the symmetric branching theory. An important parameter F was researched. The results indicated that the value of F had obvious difference at exponential and deceleration period, respectively.

Alkaline $\alpha$-amylase Production from Bacillus megaterium

Jia, Shiru,Lim, Chae-kyu,Seo, Gwang-Yeob,Nam, Hyung-Gun Korean Society for Environmental Sanitary Engineer 2009 대한환경위생공학회지 Vol.13 No.1

The enzyme expressed from strain L-49 was 2.01 times higher than that of original strain. Strain L-49 can grow on culture plate with $50{\mu}g/mL$ ampicillin. The synthesis of $\alpha$-amylase was greatly suppressed when strain L-49 was grown on monosaccharide such as glucose and polysaccharide at the same time cell concentration was low. Amylase production was enhanced when the bacterium was grown on starch and dextrin. Among different nitrogen sources tried, yeast extract was found to be the best followed by panpeptone, peptone, meat extract, bean meal, and corn steep liquor. The average rate of enzyme production was enhanced for 3~4 times in fermentation time from 24h to 44h. The sugar uptake rate has also increased. Low oxygen supply rate enhanced the rate of strain propagation but depressed the enzyme production. Hence it is benefit to obtain high enzyme activity that agitation speed maintained not lower than 400r/min and aeration rate maintained greater than 1:1vvm.

Isolation and identification of Bacillus megaterium producing Alkaline ${\alpha}$-amylase

Jia, Shiru,Choe, Yong-Deok,Cho, Hoon Korean Society for Environmental Sanitary Engineer 2008 대한환경위생공학회지 Vol.23 No.1

A bacterial strain, Bacillus megaterium L-49 has been isolated and identified that produces alkaline ${\alpha}$-amylase. The cell is ellipsoidal, about $1.0-1.2{\times}3.0-3.6{\mu}m$ in diameter, Gram-positive, motile, and central partial central. Growth occurs in media containing 7% of NaCl. This strain could utilize D-glucose, lactose, xylose, sucrose, mannose, and maltose, and but it does not utilize D-fructose, and glycogen. Among the various concentrations of saturated ammonium sulfate, the retractation ratio in range of 70 to 100% was about 93%. However, in the case of acetone, it was about 98.7%. EDTA has activating effect and Ca2+ has no effect on alkaline ${\alpha}$-amylase activity. The alkaline ${\alpha}$-amylase has low thermal stability. The optimal temperature for reaction is $50^{\circ}C$. The alkaline ${\alpha}$-amylase activity maintained stabilizing at pH 6-11 and the optimal pH for reaction was 9-10.

Characterization of Extracellular Polysaccharides from Nostoc flagelliforme Cells in Liquid Suspension Culture

Jia, Shiru,Yu, Haifeng,Lin, Yongxian,Dai, Yujie Korean Society for Biotechnology and Bioengineerin 2007 Biotechnology and Bioprocess Engineering Vol.12 No.3

Nostoc flagelliforme cells were studied with regard to the physico-chemical characterization of the extracellular polysaccharides (EPS) secreted in a liquid suspension culture. The hydrolyzed EPS were determined to be composed of four neutral sugars, which were glucose (43.2%), xylose (20.6%), galactose (29.9%), and mannose (6.3%). The glucuronic acid was the only uronic acid identified in the residue. The apparent molecular weight was estimated at $2.79{\times}10^5$. The Fourier transform infrared spectra showed that the EPS evidenced characteristics typical of non-sulfated polysaccharides. The UV spectrum and Bradford reaction indicated that there were no nucleic acids and proteins in them. The thermal analysis showed a decomposition peak at $245^{\circ}C$ on the thermogravimetric (TG) curves. The scanning electron microscope (SEM) analysis indicated that the EPS possessed a porous structure. The observed microstructural irregularities indicated that the polysaccharide was a type of amorphous solid. These results showed that the EPS of N. flagelliforme cells might be employed as a substitute for those normally derived from field colonies. The results of this study may prove to be beneficial to the protection of the natural resource represented by N. flagelliforme.

Variations in Projections of Precipitations of CMIP6 Global Climate Models under SSP 2-45 and SSP 5-85

Mohammed Sanusi Shiru,김진혁,정은성 대한토목학회 2022 KSCE Journal of Civil Engineering Vol.26 No.12

This study projects precipitation over East Asia comprising of East China, South Korea, and Japan using ten Global climate models (GCM) of the Coupled Model Intercomparison Project Phase 6 (CMIP6) and their Multi-Model Ensemble (MME). The historical GCMs were assessed using statistical metrics and compromise programming for their abilities in replicating the observed precipitation in order to assess their skills in projecting precipitation relative to the MME. Linear scaling method was used in bias correcting the GCMs using Global Precipitation Climatology Center (GPCC) as reference observed data. Probability density function and mean monthly precipitation of GCMs for the different months over the period 2021 − 2060 and 2061 − 2100 were compared with those of the observed under SSPs 2-45 and 5-85. The study revealed that NorESM2-MM, MRI-ESM2-0, MME and ACCESS-ESM1-5 have the best abilities to replicate the observed precipitation in the area of study. Under SSP 2-45, spatial projections show that the changes in precipitation for 2021 − 2060 are expected to range between -32.0 − 4.0% while those for 2061 − 2100 are -46.7 − 4.4%. Under SSP 5-85, the expected changes in precipitation range from -40 to 6.6% during 2021 to 2060 while the range is -87.3 to 6.6% with the highest decreases expected for CanESM5. The MME projects the changes of -12.0 − 6.6% during this period. The mean monthly precipitations for the different months over 2021 – 2060 and 2061 – 2100 show that while some GCMs project increases in mean monthly precipitation, others projected decreases depending on the months. Study show, no model exhibits the exact features of the observed precipitation. A model’s projection skill may be independent of its ability to replicate the properties of the observed climate. Therefore, there is a need for caution in choosing GCMs for the climate projection. This study suggests the use of the MME or the other models that have closest projections to it for climatic and hydrological studies in the region.