• Journal of Applied Biological Chemistry
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• v.53 no.3
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• pp.174-178
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• 2010

Calcium and iron binding peptides were prepared by enzymatic hydrolysis and ultrafiltration of rice bran protein (RBP), which was isolated from defatted rice bran by phytase and xylanase treatment and ultrasonication. The isolated RBP had a molecular weight in the range of 10-66 kDa. The extracted proteins were hydrolyzed using Flavourzyme for 6 hr. After ultrafiltration under 5 kDa as molecular weight, the peptides were fractionated into 4 peaks by Sephadex G-15 gel permeation chromatography, and each fraction was determined for calcium and iron binding activity. As the result, Fl and F2 fractions were the best candidate for calcium and iron chelation, respectively. These results suggest that the calcium and iron binding peptides can be used as functional food additives in food industry.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.11
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• pp.1555-1565
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• 2009

Anaerobic rumen fungi have been regarded as good genetic resources for enzyme production which might be useful for feed supplements, bio-energy production, bio-remediation and other industrial purposes. In this study, an expressed sequence tag (EST) library of the rumen anaerobic fungus Neocallimastix frontalis was constructed and functional genes from the EST library were analyzed to elucidate carbohydrate metabolism of anaerobic fungi. From 10,080 acquired clones, 9,569 clones with average size of 628 bp were selected for analysis. After the assembling process, 1,410 contigs were assembled and 1,369 sequences remained as singletons. 1,192 sequences were matched with proteins in the public data base with known function and 693 of them were matched with proteins isolated from fungi. One hundred and fifty four sequences were classified as genes related with biological process and 328 sequences were classified as genes related with cellular components. Most of the enzymes in the pathway of glucose metabolism were successfully isolated via construction of 10,080 ESTs. Four kinds of hemi-cellulase were isolated such as mannanase, xylose isomerase, xylan esterase, and xylanase. Five $\beta$-glucosidases with at least three different conserved domain structures were isolated. Ten cellulases with at least five different conserved domain structures were isolated. This is the first solid data supporting the expression of a multiple enzyme system in the fungus N. frontalis for polysaccharide hydrolysis.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.988-1001
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• 1999

The rumen ecosystem is increasingly being recognized as a promising source of superior polysaccharide-degrading enzymes. They contain a wide array of novel enzymes at the levels of specific activities of 1,184, 1,069, 119, 390, 327 and $946{\mu}mol$ Reducing sugar release/min/mg protein for endoglucanase, xylanase, polygalactouronase, amylase, glucanase and arabinase, respectively. These enzymes are mainly located in the surface of rumen microbes. However, glycoside-degrading enzymes (e.g. glucosidase, fucosidase, xylosidase and arabinofuranosidase, etc.) are mainly located in the rumen fluid, when detected enzyme activities according to the ruminal compartments (e.g. enzymes in whole rumen contents, feed-associated enzymes, microbial cell-associated enzymes, and enzymes in the rumen fluid). Ruminal fungi are the primary contributors to high production of novel enzymes; the bacteria and protozoa also have important functions, but less central roles. The enzyme activities of bacteria, protozoa and fungi were detected 32.26, 19.21 and 47.60 mol glucose release/min/mL mediem for cellulose; 42.56, 14.96 and 64.93 mmol xylose release/min/mL medium after 48h incubation, respectively. The polysachharide-degrading enzyme activity of ruminal anaerobic fungi (e.g. Neocallimastix patriciarum and Piromyces communis, etc.) was much higher approximately 3~6 times than that of aerobic fungi (e.g. Tricoderma reesei, T. viridae and Aspergillus oryzae, etc.) used widely in industrial process. Therefore, the rumen ecosystem could be a growing source of novel enzymes having a tremendous potential for industrial applications.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.12
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• pp.1676-1685
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• 2009

This trial was conducted to determine the effects of various feed additives on nutrient digestibility, performance and carcass traits of growing-finishing pigs fed diets containing wheat distiller' grains with solubles (WDGS). Seventy-two, individually fed pigs (19.7${\pm}$2.6 kg), were assigned to one of six dietary treatments in a 6${\times}$2 (treatment${\times}$sex) factorial design (N = 12). The control diet was based on wheat and soybean meal while the five experimental diets contained 20% WDGS during the growing period and 12% WDGS during the finishing period. One 20% WDGS diet was unsupplemented while the remaining diets were supplemented with either 0.1% threonine, 5% canola oil, 0.2% enzyme (0.1% Endofeed W containing 1,250 units/g of xylanase and 385 units/g of $\beta$-glucanase and 0.1% Vegpro containing 7,700 HUT/g protease and 75 CMC/g cellulase), or a combination of the three additives at the same levels as those fed separately. The digestibility of dry matter, crude protein and energy were all significantly higher in the control diet than the unsupplemented diet containing 20% WDGS. None of the feed additives improved nutrient digestibility. In addition, none of the additives had any significant effect on gain or feed intake during the growing (19.7 to 43.6) or finishing (43.6 to 114.3 kg) periods or overall (19.7 to 114.3 kg). During the growing period, feed conversion was significantly improved for pigs fed the combination of additives compared with the unsupplemented WDGS diet. During the finishing period and overall, feed conversion was significantly improved for pigs fed 5% canola oil alone or in combination with the other additives. None of the supplements had any effect on carcass traits. These results indicate that WDGS can be successfully used as a partial replacement for soybean meal in diets fed to growingfinishing pigs. However, due to its low energy content, there may be some merit in including high energy ingredients such as canola oil when diets containing WDGS are fed.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.6
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• pp.810-817
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• 2011

A feeding trial was conducted to study the effect of tannin rich Pakar (Ficus infectoria) leaves on microbial profile, rumen fermentation and nutrient utilization in goats. Eight goats divided in two groups were fed pakar leaves (experimental group) and green oats (control group) as sole roughage source along with a fixed quantity of concentrate mixture for a period of 3 months. Two metabolic trials of six days duration were conducted after 30 and 90 days of experimental feeding. The dry matter intake was significantly higher (p<0.05) and digestibility's of DM, OM, CP, EE, NDF and ADF were reduced in experimental as compared with the control group. The TDN intake was similar (236.52 vs. 240.39 g/d) in both the groups. All the animals were in positive nitrogen balance. The concentration of ammonia nitrogen, TVFA, lactic acid and activities of xylanase and protease were reduced in pakar leaves fed goats. The rumen microbial profile as obtained by MPN technique showed no change in total bacterial population but total fungi and cellulolytic bacteria were reduced (p<0.05), whereas, tannin degrading/tolerant bacteria increased with the feeding of pakar leaves. Real time PCR data revealed a decrease in Ruminococcus flavefaciens, an increase in methanogens and no change in the Fibrobacter succinogenes population by feeding of pakar leaves.

• Mycobiology
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• v.43 no.4
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• pp.458-466
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• 2015

Oak tree death caused by symbiosis of an ambrosia beetle, Platypus koryoensis, and an ophiostomatoid filamentous fungus, Raffaelea quercus-mongolicae, has been a nationwide problem in Korea since 2004. In this study, we surveyed the yeast species associated with P. koryoensis to better understand the diversity of fungal associates of the beetle pest. In 2009, a total of 195 yeast isolates were sampled from larvae and adult beetles (female and male) of P. koryoensis in Cheonan, Goyang, and Paju; 8 species were identified by based on their morphological, biochemical and molecular analyses. Meyerozyma guilliermondii and Candida kashinagacola were found to be the two dominant species. Among the 8 species, Candida homilentoma was a newly recorded yeast species in Korea, and thus, its mycological characteristics were described. The P. koryoensis symbiont R. quercusmongolicae did not show extracelluar CM-cellulase, xylanase and avicelase activity that are responsible for degradation of wood structure; however, C. kashinagacola and M. guilliermondii did show the three extracellular enzymatic activities. Extracelluar CM-cellulase activity was also found in Ambrosiozyma sp., C. homilentoma, C. kashinagacola, and Candida sp. Extracelluar pectinase activity was detected in Ambrosiozyma sp., C. homilentoma, Candida sp., and M. guilliermondii. All the 8 yeast species displayed compatible relationships with R. quercus-mongolicae when they were co-cultivated on yeast extract-malt extract plates. Overall, our results demonstrated that P. koryoensis carries the yeast species as a symbiotic fungal associate. This is first report of yeast diversity associated with P. koryoensis.

• The Plant Pathology Journal
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• v.27 no.1
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• pp.89-92
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• 2011

Cyclic AMP receptor-like protein (Clp), is known to be a global transcriptional regulator for the expression of virulence factors in Xanthomonas campestris pv. campestris (Xcc). Sequence analysis showed that Xanthomonas oryzae pv. oryzae (Xoo) contains a gene that is strongly homologous to the Xcc clp. In order to determine the role of the Clp homolog in Xoo, a marker exchange mutant of $clp_{xoo4158}$ was generated. Virulence and virulence factors, such as the production of cellulase, xylanase, and extracellular polysaccharides (EPS) and swarming motility were significantly decreased in the $clp_{xoo4158}$ mutant. Moreover, the mutation caused the strain to be more sensitive to hydrogen peroxide and to over-produce siderophores. Complementation of the mutant restored the mutation-related phenotypes. Expression of $clp_{xoo4158}$, assessed by reverse-transcription realtime PCR and clp promoter activity, was significantly reduced in the rpfB, rpfF, rpfC, and rpfG mutants. These results suggest that the clp homolog, $clp_{xoo4158}$, is involved in the control of virulence and resistance against oxidative stress, and that expression of the gene is controlled by RpfC and RpfG through a diffusible signal factor (DSF) signal in Xanthomonas oryzae pv. oryzae KACC10859.

• The Plant Pathology Journal
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• v.35 no.6
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• pp.674-683
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• 2019

Some species of the Trichoderma genus are reported as the major problem in oak wood mushroom production in Korea. In spite of economic loss by the fungi, scientific information on airborne Trichoderma species is not much available. To generate information for disease management development we analyzed airborne Trichoderma. A total of 1,063 fungal isolates were purely obtained from indoor air sampling of cultivation houses used for oak wood mushroom using sawdust media. Among the obtained isolates, 248 isolates were identified as Trichoderma fungi including T. harzianum, T. atroviride, T. citrinoviride, and T. pseudokoningii, by morphological and molecular analysis. T. harzianum was dominant among the four identified species. All the four Trichoderma species grew fast on solid nutrient media tested (potato dextrose agar [PDA], malt extract agar [MEA], Czapek's Dox + yeast extract agar [CYA] and cornmeal dextrose agar). Compact mycelia growth and mass spore production were better on PDA and CYA. In addition, T. harzianum and T. citrinoviride formed greenish and yellowish mycelium and spores on PDA and CYA. Greenish and yellowish pigment was saturated into PDA only by T. pseudokoningii. These four Trichoderma species could produce extracellular enzymes of sawdust substrate degradation such as β-glucosidase, avicelase, CM-cellulase, amylase, pectinase, xylanase, and protease. Their mycelia inhibited the growth of oak wood mushroom mycelia of two tested cultivars on dual culture assay. Among of eleven antifungal agents tested, benomyl was the best to inhibit the growth of the four Trichoderma species. Our results demonstrate that the airborne Trichoderma fungi need to be properly managed in the cultivation houses for safe mushroom production.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.8
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• pp.1110-1115
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• 2005

To study the effect of feeding lactic acid producing bacteria on the performance of cattle calves, twenty four, day old male crossbred cattle calves (Bos indicus${\times}$Bos taurus), were distributed into two groups of 12 animals each. The animals were fed on calf starter containing wheat bran and green berseem ad libitum and milk as per requirement upto 8 weeks of age. The diet of calves of Group 2 was supplemented with 500 ml culture of Lactobacillus acidophilus-15. Total duration of the experiment was 31 weeks. There was no significant difference in intake and digestibility of dry matter (DM), organic matter (OM), neutral detergent fibre (NDF), acid detergent fibre (ADF) and crude protein (CP) between the groups. The rumen pH, protozoa numbers, concentration of volatile fatty acids (VFA), ammonia nitrogen ($NH_3-N$), trichloroacetic acid precipitable nitrogen (TCA-ppt N) and activity of microbial enzymes (carboxymethylcellulase, xylanase, amylase and protease) were not affected due to probiotic supplementation. Average live weight gain of the calves was improved (about 10%) and feed:gain ratio was reduced (about 5%) in the animals given Lactobacillus culture. The data indicated that crossbred calves could be reared on a diet devoid of cereal grain and addition of Lactobacillus culture in the diet resulted in an added advantage in growth performance of the animals.

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1681-1691
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• 2012

This work was conducted to evaluate the effect of dilute sodium hydroxide (NaOH) on barley straw at boiling temperature and fractionation of its biomass components into lignin, hemicellulose, and reducing sugars. To this end, various concentrations of NaOH (0.5% to 2%) were applied for pretreatment of barley straw at $105^{\circ}C$ for 10 min. Scanning electron microscopy (SEM), atomic force microscopy (AFM), and Fourier transform infrared (FTIR) spectroscopy studies revealed that 2% NaOH-pretreated barley straw exposed cellulose fibers on which surface granules were abolished due to comprehensive removal of lignin and hemicellulose. The X-ray diffractometer (XRD) result showed that the crystalline index was increased with increased concentration of NaOH and found a maximum 71.5% for 2% NaOH-pretreated sample. The maximum removal of lignin and hemicellulose was 84.8% and 79.5% from 2% NaOH-pretreated liquor, respectively. Reducing sugar yield was 86.5% from 2% NaOH-pretreated sample using an enzyme dose containing 20 FPU of cellulase, 40 IU of ${\beta}$-glucosidase, and 4 FXU of xylanase/g substrate. The results of this study suggest that it is possible to produce the bioethanol precursor from barley straw using 2% NaOH at boiling temperature.