• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.380-387
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• 2002

To investigate the effects of xylooligosaccharides on the in vitro growth of intestinal bacteria, various species were cultivated individually on the m-PYF medium containing a carbon source (0.5% w/v) such as xylooligosaccharides, isomaltooligosaccharides, fructooligosaccharides and sucrose, respectively. The health-promoting microorganisms such as Bifidobacterium bifidum, Bifidobacterium infantis, Bifidobacterium longum, Lactobacillus casei and Lactobacillus acidophilus grew more effectively by xylooligosaccharides than by other carbon source, though xylooligosaccharides inhibited the growth of Clostridium perfringens, Bacteroides fragilis, Escherichia coli, Staphylococcus aureus and Salmonella typhumurium. At the mixed culture xylooligosaccharides exerted a preferential stimulatory effects on numbers of the health-promoting microorganisms, while xylooligosaccharides inhibited populations of potential pathogens at relatively low level. Xylooligosaccharides also maintained the acidity of culture with Streptococcus mutans, caries-inducing bacteria, over pH 5.0. These results suggest that xylooligosaccharides selectively promote the growth of the health-promoting microorganisms in human intestine and prevent caries by inhibiting acid production from Streptococcu mutans.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.6
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• pp.1190-1196
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• 2001

This study was conducted to examine the effects of dietary xylooligosaccharides on HMG-CoA reductase activity and lipid composition of liver in rat fed high cholesterol diet. Sprague-Dawley male rats weighing 100 $\pm$ 10 g were randomly divided into groups of one normal diet, and four high cholesterol diet containing 1% cholesterol. The high cholesterol (1%) diet groups were classified into xylooligosaccharides free diet (C group), 5% xylooligosaccharides diet (C5XO group), 10% xylooligosaccharides diet (C10XO group), and 15% xylooligosaccharides diet (C15XO grcup) according to the levels of dietary xylooligosaccharides supplementation. The experimental diets were fed ad libitum for 4 weeks. The hepatic lipid contents, cholesterol and triglycerides in xylooligosaccharides supplemented groups were significantly lower than those of C group. An antithrombGsis index, a ratio of n-3 to n-6 fatty acids of liver was significantly increased in 10% xylooligosaccharides supplemented groups compared to that of C group. The activity of hepatic HMG-CoA reductase, a rate limiting enzyme of cholesterol biosynthesis, in xylooligosaccharides supplemented groups was more significantly increased than in C group. These results suggest that dietary xylooligosaccharide may be act as potential substitute for a dietary fiber to improve lipids metabolism in rat fed high cholesterol diet.

• Microbiology and Biotechnology Letters
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• v.36 no.4
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• pp.307-313
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• 2008

The yeast surface expression system, pCTXYN (6.8 kb), of Bacillus endoxylanase gene (xynB, 642 bp) was constructed and introduced into Saccharomyces cerevisiae EBY100 cell. The transformed yeast cell showing the highest endoxylanase activity was selected through the active staining of colonies grown on YPDG medium containing xylan. With the yeast transformant, EBY100/pCTXYN, grown on galactose containing medium, it was found that the endoxylanase was successfully displayed on the yeast cell surface and the xylooligosaccharides were efficiently produced from xylan. The most of endoxylanase activity was detected in the cell fraction and reached about 1.9 unit/mL after 48 h cultivation. The optimized conditions for xylooligosaccharides production from xylan were determined as follows: substrate and its concentration, oat spelt xylan 6%; concentration of yeast whole-cell, 5 unit/mL; temperature, $50^{\circ}C$, and reaction time $2{\sim}4\;h$. When the oat spelts xylan and corncob xylan were hydrolyzed by treatment with cell surface-displayed endoxylanase, xylotriose was formed as a main product.

• Microbiology and Biotechnology Letters
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• v.29 no.4
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• pp.221-226
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• 2001

Streptomyces themocyaneovio-laceus producing the thermostable xylanase was used for the production of xylooligosaccharides from xylan. The optimal conditions for the xylanase production were investigated in jar fermentor, which operated at 2 vvm aera-tion and 400 rpm agitation speed at $50^{\circ}C$ for 24 h. The optimal reaction condtion for the production of xylooli-gosaccharides with xylanases which were prepared by the percipitation with ammonium sulfate were obtained by the reaction at $60^{\circ}C$ for 12 h in the mixture composed of 10% birchwood xylan in 50 mM sodium phosphate buffer (pH 6.0)and 10 unit/ml of xylanase. In this optimal condition for the xylooligosaccharides production the mixture of xylooligosaccharides (58.8 g/I) which were composed of 20.1 g/I of xyobiose, 8.9 g/I of xylotriose 4.5 g/I of xylotetraose 16.2g/I of xylopentaose and 9.1 g/I xylohexaose and 5.0 g/I of xylose was produced from 100 g/I of birchwood xylan by the xylanases of S thermocyaneoviolaceus .

• Journal of Nutrition and Health
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• v.35 no.10
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• pp.1015-1022
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• 2002

This study was conducted to examine the effects of dietary xylooligosaccharides on hepatic HMG-CoA reductase activity and morphological exchange of liver in rats fed high fat diet. Sprague-Dawley male rats weighing 100 $\pm$ 10 g were randomly divided into four groups, two normal diets and two high fat diets containing 1% cholesterol and 10% lard. Two normal diets were classified into a basal diet (normal group) and 10% xylooligosaccharide diet (NX group). The high fat diet groups were classified into a HF group without xylooligosaccharides diet and HFX group supplemented 10% xylooligosacchride diet. Experimental diets were fed ad libidum to the rats for 4 weeks and then they were sacrificed. The body weight of high fat diet (HF group) was increased more than that of normal group, but it was significantly decreased by xylooligosacchrides supplementation. The food intake was not significantly different among the all groups. The weight of liver, small intestine and cecum of all xylooligosaccharide supplemented groups were significantly heavier than those of normal and HF groups. The activity of hepatic HMG-CoA reductase, a rate limiting enzyme of cholesterol biosynthesis, in xylooligosaccharide supplemented groups was higher than that of HF group. Light micrographs revealed that the structures of hepatocytes in xylooligosaccharide supplemented groups were preserved well, compared to HF group. The xylooligosaccharide supplementation exerted a lipid-lowering action by decreasing cholesterol and triglycerides contents in hepatic tissue. In conclusion, the activity of hepatic HMG-CoA reductase and damage of liver in rats fed high fat diets were improved by dietary xylooligosaccharides.

• Journal of Nutrition and Health
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• v.35 no.10
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• pp.1023-1030
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• 2002

This study was conducted to examine the effects of dietary xylooligosaccharides on lipoprotein lipase (LPL) activitiy in epididymal adipose tissue and lipid composition in serum of rats fed normal or high fat diet. Male Sprague-Dawley male rats weighing 100 $\pm$ 10 g were randomly divided into four groups, two normal diets and two high fat diets containing 1% cholesterol and 10% lard. Two normal diets were classified into a basal diet (normal group) and that with 10% xylooligosaccharide diet (NX group). The high fat diet groups were classified into a HF group without xylooligosaccharides diet and HFX group supplemented with 10% xylooligosacchride diet. Experimental diets were fed ad libitum to the rats for 4 weeks and then they were sacrificed. Body weight, epididymal weight and abdominal weight in HF group were hevier than the those of normal group, but HFX group was significantly reduced compared to HF group. Relative body weight to epididymal weight and relative body weight to abdominal weight in HF group were increased to 50%, 51%, respectively, compared to normal group, but HFX group was reduced 22%, 16%, respectively, compared to HF group. The levels of serum triglyceride, total cholesterol, LDL-cholesterol and atherogenic index in HFX groups were significantly lower than those of HF group, whereas HDL-cholesterol levels were significant increased. Triglyceride contents of epididymal adipose tissue in HF group was increased to 39%, compared to normal group, but HFX group was reduced to 15.8%, compared to HF group. Cholesterol contents of epididymal adipose tissue in HF group was increased 121%, compared to normal group, but HFX group was reduced to 26%, compared to HF group. The activity of LPL in epididymal adipose tissue was increased to 259% in HF group, compared to normal group and HFX group was reduced to 66%, compared to HF group. These result of this study suggested that improved lipid metabolism observed in rats fed xylooligosaccharides may be caused by an alteration of LPL activity in epididymal adipose tissue and lipid composition in serum.

• Journal of Microbiology and Biotechnology
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• v.22 no.8
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• pp.1084-1091
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• 2012

Xylooligosaccharides are functional foods mainly produced during the hydrolysis of xylan by physical, chemical, or enzymatic methods. In this study, production of xylobiose was investigated using oil palm empty fruit bunch fiber (OPEFB) as a source material, by chemical and enzymatic methods. Xylanase-specific xylan hydrolysis followed by xylobiose production was observed. Among different xylanases, xylanase from FXY-1 released maximum xylobiose from pretreated OPEFB fiber, and this fungal strain was identified as Aspergillus terreus and subsequently deposited under the accession Number MTCC- 8661. The imperative role of lignin on xylooligosaccharides enzymatic synthesis was exemplified with the notice of xylobiose production only with delignified material. A maximum 262 mg of xylobiose was produced from 1.0 g of pretreated OPEFB fiber using FXY-1 xylanase (6,200 U/ml) at pH 6.0 and $45^{\circ}C$. At optimized environment, the yield of xylobiose was improved to 78.67 g/100 g (based on xylan in the pretreated OPEFB fiber).

• Korean Journal of Microbiology
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• v.46 no.3
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• pp.308-312
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• 2010

Deinococcus geothermalis is a moderate thermophillic radiation resistant bacterium producing greater abundance of sugar metabolism enzymes than other Deinococcus species. In this study, optimal condition for xylanolytic activity of D. geothermalis was determined and xylooligosaccharides from oat spelt, beechwood, and birchwood xylan hydrolysates by this organism were analyzed through HPLC. Reducing sugar yield was increased in the order of beechwood, birchwood, and oat spelt xylan. D. geothermalis displayed maximal xylanolytic activity at $40^{\circ}C$ and pH 8.0. Magnesium ion increased xylanolytic activity upto 7.5 fold. Six kinds of xylooligosaccharides (xylose, xylobios, xylotriose, xylotetraose, xylopentaose, and xylohexalose) were detected from beechwood and birchwood xylan reaction products. Among them, xylose was the major product. However, only three kinds of xylooligosaccharides (xylose, xylopentaose, and xylohexalose) were clearly detected from oat spelt xylan. Gamma-ray (50 kGy) treatment of beechwood xylan, birchwood xylan and oat spelt xylan increased xylanolytic activity of D. geothermalis. The results indicate that D. geothermalis and pretreatment of radiation is useful for xylooligosaccharides production.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.312-316
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• 2000

Crude xylooligosaccharides(XO) were separated with a cellulose membrane (10,000 molecular weight cut-off). Flux variation was measured at transmembrane pressures of 5, 10, 20 and 30 psi, while flow rates were maintained at 100, 200, 300 and 400 ml/min and temperatures at 10, 20, 23-25 and $30^{\circ}C$. Optimal conditions were found at the transmembrane pressure of 20 psi, the flow rate of 300 ml/min and the temperature of $23-25^{\circ}C$, where the flux was decreasing with time by 62% after 200 min. Total sugar, total solid and ash contents were rather independent of ultrafiltration but protein was removed up to 55% from crude XO. Especially, the use of ultrafiltration was very effective for decolorization (84%) of crude XO. These results suggest that ultrafiltration is a useful method for the primary purification of XO.

• Food Industry And Nutrition
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• v.6 no.1
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• pp.21-24
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• 2001