• KSBB Journal
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• v.9 no.4
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• pp.428-435
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• 1994

Cell growth and production of ${\alpha}$-amylase, acetic acid and lactic acid were investigated in Bacillus amyloliquefaciens(ATCC 23350) flask culture with various carbon sources. Maximum dry cell density increased with increase in initial maltose concentration. Maximum dry cell density was the highest(1.4g/$\ell$) at 10g/$\ell$ of initial glucose concentration. With 10g/$\ell$ of initial glucose concentration, maximum specific cell growth rate was obtained. Among the various carbon sources maximum ${\alpha}$-amylase production was obtained with 149 unit/ml at 20g/$\ell$ of initial maltose concentration. With 5g/$\ell$ of initial maltose concentration, maximum ${\alpha}$-amylase production rate was obtained. By increasing carbon source concentration, acetic acid formation decreased. Acetic acid formation was higher in glucose than in maltose. By increasing carbon source concentration, lactic acid formation increased. Lactic acid formation was higher in maltose than in glucose.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.2
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• pp.82-86
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• 1998

The maltose binding protein (MBP) fusion protein system is a versatile tool to express and isolate recombinant proteins in E. coli. In this system, MBP fusion proteins are efficiently isolated from whole cell lysate using amylose conjugated agarose beads and then eluted by competition with free maltose. Since MBP is a rather large molecule (∼42 kDa), for further experiments, the MBP part is usually proteolytically cleaved from the fusion protein and subsequently removed by ion-exchange chromatography or rebinding to amylose columns after washing out excess and MBP-bound maltose. In the present study, we have developed an improved method for the removal of cleaved MBP, which is advantageous over conventional methods. In this method, factor Xa cleaved MBP fusion proteins were incubated with Sepharose beads conjugated with MBP specific monoclonal antibodies and then precipitated buy centrifugation, resulting in highly purified proteins in the supernatant.

• KSBB Journal
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• v.9 no.2
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• pp.122-126
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• 1994

A new method for the production of isomalto-oligosaccharides from maltose was investigated using intact cells of Aureobasidium pullulaans which had been known to produce fructo-oligosaccharides. The cells showed transglucosylation activity producing isomalto-oligosaccharides at high concentrations of maltose, while they showed a hydrolytic activity at low concentrations of substrate when cultivated at $25^{\circ}C$. The optimum reaction conditions for the isomalto-oligosaccharide production were as follows: substrate concentration, 500g/l maltose; pH, 4.5; temperature, $65^{\circ}C$; cell dosage, 10 unit per gram substrate. Under optimized conditions, the maximum yield of isomalto-oligosaccharides achieved was around 48% (w/w). At the early period of reaction, panose was selectively produced from maltose, and thereafter isomaltotriose was synthesized by utilizing panose as a substrate when maltose consumption was discontinued.

• Microbiology and Biotechnology Letters
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• v.22 no.1
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• pp.106-113
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• 1994

A novel method for production of concentrated purity maltose using swollen extruded corn starch was investigated. Degree of gelatinization of extruded starch suitable for maltose formation was found to be around 70%. The optimal amiunt of enzyme was 400 unit fungal $\alpha $-amylase per g of starch, and the reaction time was 12 hours. At extruded starch concentration of 300 g/l(w/v), maltose concentration and content were reached up to 220 g/l(w/v) and 77%(w/w), respectively. The maltose forming reaction was also successfully proceeded at high starch concentration of 700 g/l(w/v), however, the conversion yield and content were decreased. By the addition of extruded starch by fed-batch wise, the maltose concentration, purity, and conversion yield could be improved up to 465 g/l(w/v), 70%(w/w), and 0.63, respectively. The investigated maltose production process seems to have many potential advantages over the conventional process utilizing liquefied starch, and the feasibility for industrial application needs to be evaluated.

• Journal of Life Science
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• v.10 no.2
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• pp.125-130
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• 2000

To overproduce endoxylanase from a recombinant Bacillus subtilis harboring the pJHKJ4 plasmid, the effects of carbon and nitrogen sources on the cell growth and expression level of endoxylanase were investigated in the flask cultures. Among the various carbon and nitrogen sources tested, glucose and maltose as carbon source and yeast extract as nitrogen source were found to be the most effective for the cell growth and the endoxylanase expression. When the concentration of glucose was increased from 0.5% to 5%, the highest activity of extracellular endoxylanse, 166 unit/$m\ell$, was observed at 2% glucose. In case of maltose, the endoxylanase was stably produced at the level of 180 unit/$m\ell$, regardless of the concentration of maltose. The higher the concentration of yeast extract, the greater cell growth and endoxylanase expression were obtained. However, the highest endoxylanase activity per unit cell mass was observed with 1% yeast extract. With the optimized medium (2% glucose, 1% yeast extract, etc), about 630 unit/$m\ell$ of endoxylanse was expressed through the batch fermentation in a fermentor, which expression level corresponded to about 0.7 g-endoxylanase protein /$\ell$. It was also found that the plasmid was stably maintained above 70% level, and more than 90% of endoxylanase activity was detected in the extracellular medium.

• KSBB Journal
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• v.11 no.2
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• pp.125-131
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• 1996

In this study, Bucillus amyloliquefaciens was adopted as bacterial source to investigate the concentration of carbon source by adding inhibitors in the batch culture. By adding acetic acid at $10g/\ell$ of initial glucose concentration, maximum dry cell density was obtained with the highest value of /$\3.9gell$ at $1.0g/\ell$ of initial acetic acid concentration. By adding acetic acid al 10g/$\ell$ of initial glucose concentration, maximum ${\alpha}$-amylase production was obtained with 331.55unit/m1 at $2.0g/\ell$ of initial acetic acid concentration. ${\alpha}$-Amylase production was decreased with the increase of initial acetic acrid concentration. By adding acetic acid to the medium, cell growth and ${\alpha}$-amylase production was higher in glucose than in maltose. By adding lactic acid to the medium, cell growth was decreased.

• Applied Biological Chemistry
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• v.43 no.1
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• pp.12-17
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• 2000

For the enzymatic production of $2-O-{\alpha}-D-glucopyranosyl-L-ascorbic$ acid (AA-2G) from ascorbic acid, rice seed was used as the source of ${\alpha}-glucosidase$ having transglucosylation activity. Among six rice varieties, cultivated in Korea, ${\alpha}-glucosidase$ activity of Oryza savita L. cv. Ilpumbyeo was the highest with 125.03 unit/ml and it had maximum specific activity with 8.52 unit/mg protein when rice seeds were grown for 3 days after germination. For the production of AA-2G using crude extract of O. savita L. cv. Ilpumbyeo, maltose was most effective glucose donor. The optimum concentration of maltose and ascorbic acid were 125 mM and 175 mM, respectively. The optimum concentration of ${\alpha}-glucosidase$ was 100 unit. The most effective buffer was 100 mM sodium citrate. The optimum pH and temperature were 5.0 and $60^{\circ}C$, respectively. Under the optimum condition, $108.43\;{\mu}M/unit$ of AA-2G was produced from ascorbic acid after 35 minutes of reaction, which corresponds to 6.2% of conversion ratio based on the amount of ascorbic acid used.

• Korean journal of food and cookery science
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• v.14 no.2
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• pp.182-187
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• 1998

The changes in weight, reducing sugar content, sugar composition and enzyme activities (${\beta}$-amylase and invertase) of sweet potato were studied with three kinds of cooking methods, microwave oven, gas oven, and steaming. The weights of sweet potato cooked by microwave oven and gas oven were decreased with increasing cooking time, whereas that of steaming was increased with cooking time. Reducing sugar content of sweet potato cooked by microwave oven was increased till 40 seconds, but decreased thereafter. In the cooking methods using gas oven and steaming, reducing sugar content were increased with cooking time. And reducing sugar content were 334.60 mg/g and 381.29 mg/g, respectively at 100$^{\circ}C$ of cold point in sweet potato cooked by gas oven and steaming. Raw sweet potato consisted of fructose (1.56 mg/g), glucose (1.79 mg/g), sucrose (5.58 mg/g), and maltose (2.22 mg/g). The contents of fructose, glucose, and sucrose were decreased during cooking process. But maltose content was increased with cooking time. Especially, maltose contents were 24.81 mg/g and 28.10 mg/g at 100$^{\circ}C$ of cold point in sweet potato cooked by gas oven and steaming. The activities of ${\beta}$-amylase and invertase were decreased with cooking time. Microwave oven-cooked sweet potato did not show on invertase activity.

• Preventive Nutrition and Food Science
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• v.21 no.2
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• pp.124-131
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• 2016

Among 116 bacterial strains isolated from Korean fermented foods, one strain (SS-76) was selected for producing new oligosaccharides in a basal medium containing maltose as the sole source of carbon. Upon morphological characterization using scanning electron microscopy, the cells of strain SS-76 appeared rod-shaped; subsequent 16S rRNA gene sequence analysis revealed that strain SS-76 was phylogenetically close to Bacillus subtilis. The main oligosaccharide fraction B extracted from the culture supernatant of B. subtilis SS-76 was purified by high performance liquid chromatography. Subsequent structural analysis revealed that this oligosaccharide consisted only of glucose, and methylation analysis indicated similar proportions of glucopyranosides in the 6-linkage, 4-linkage, and non-reducing terminal positions. Matrix-assisted laser-induced/ionization time-of-flight/mass spectrometry and electrospray ionization-based liquid chromatography-mass spectrometry/mass spectrometry analyses suggested that this oligosaccharide consisted of a trisaccharide unit with 1,6- and 1,4-glycosidic linkages. The anomeric signals in the $^1H$-nuclear magnetic resonance spectrum corresponded to ${\alpha}$-anomeric configurations, and the trisaccharide was finally identified as panose (${\alpha}$-D-glucopyranosyl-1,6-${\alpha}$-D-glucopyranosyl-1,4-D-glucose). These results suggest that B. subtilis SS-76 converts maltose into panose; strain SS-76 may thus find industrial application in the production of panose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.81-86
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• 1997

Spray dried powdered juice was processed from concentrated extract of jujube(Zizyphus jujuba MILLER). Spray drying of the extract solution could not be operated to have powder product by itself over whole concentration range and required addition of some carrier or support material. The concentrated extract of 26$^{\circ}$Bx was combined with carrier material solution to have a final concentration of 30$^{\circ}$Bx, and then spray dried. Proper addition level of carrier solid for physical and flavor quality of the powder product was determined to be 1 : 1 ratio to jujube solid. Combined use of maltose and gum arabic produced the best quality product among the studied carrier materials, which were maltose, dextrin, condensed milk and gum arabic. Enzymatic treatment in extraction process could increase the yield by 13~39%, but hurt the sensory quality of powdered juice. Treatment by 0.5% pectinase(0.05 unit/ml) may be used with lesser quality change for improved yield.