• 한국작물학회:학술대회논문집
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• 한국작물학회 2021년도 추계학술대회
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• pp.162-162
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• 2021

• Asian-Australasian Journal of Animal Sciences
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• 제13권10호
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• pp.1399-1406
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• 2000

A continuous culture study was conducted to determine the impact of ruminal degradable soy protein (S-RDP) level and dilution rate (D) on growth of ruminal non-structural carbohydrate-fermenting microbes. Corn starch, urea and isolated soy protein (ISP) were used to formulate three diets with S-RDP levels of 0, 35 and 70% of total dietary CP. Two Ds were 0.03 and $0.06h^{-1}$ of the fermenter volume in a single-effluent continuous culture system. As S-RDP levels increased, digestibilities of dietary dry matter (DM), organic matter (OM) and crude protein (CP) linearly (p=0.001) decreased, whereas digestion of dietary starch linearly (p=0.001) increased. Increasing D from 0.03 to $0.06h^{-1}$ resulted in decreased digestibilities of dietary DM and OM, but had no effect on digestibilities of dietary starch (p=0.77) and CP (p=0.103). Fermenter pH, the concentration of volatile fatty acids (VFA) and daily VFA production were unaffected (p=0.159-0.517) by S-RDP levels. Molar percentages of acetate, propionate and butyrate were greatly affected by S-RDP levels (p=0.016-0.091), but unaffected by D (p=0.331-0.442). With increasing S-RDP levels and D, daily bacterial counts, daily microbial N production (DMNP) and microbial efficiency (MOEFF; grams of microbial N produced per kilogram of OM truly digested) were enhanced (p=0.001). The increased microbial efficiency with increasing S-RDP levels is probably the result of peptides or amino acids that served as a stimulus for optimal protein synthesis. The quantity of ruminal degradable protein from soy proteins required for optimum protein synthesis of non-structural carbohydrate-fermenting microbes appears to be equivalent to 9.5% of dietary fermented OM.

• 한국토양비료학회지
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• 제49권2호
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• pp.125-131
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• 2016

The biodegradable film application can escape from plastic environmental pollution. This experiments studied the effect of biodegradable mulch film on the soil microbial community using fatty acid methyl ester method in soybean production field. The soil $NO_3$-N content in polyethylene mulch film (PE) soil was significantly higher than biodegradable mulch film soil (p < 0.05). The soil microbial community of Gram negative bacteria showed significantly higher in biodegradable mulch film soil than PE mulch film soil (p < 0.05). In addition, biodegradable mulch film soil had significantly low ratio of cy17:0 to $16:1{\omega}7c$ and cy19:0 to $18:1{\omega}7c$ compared with those of PE mulch film soil (p < 0.05), indicating that microbial stress decreased. The ratio of cy17:0 to $16:1{\omega}7c$ and cy19:0 to $18:1{\omega}7c$ should be considered as a potential responsible factor for the obvious differentiation that was observed between the biodegradable mulch film soil and PE mulch film soil in a upland field. The results of this experimentation show the potential of using biodegradable mulch film in place of PE.

• The Plant Pathology Journal
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• 제30권1호
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• pp.33-42
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• 2014

Nivalenol (NIV) and deoxynivalenol (DON) are predominant Fusarium-producing mycotoxins found in grains, which are mainly produced by Fusarium asiaticum and F. graminearum. NIV is found in most of cereals grown in Korea, but the genetic basis for NIV production by F. asiaticum has not been extensively explored. In this study, 12 genes belonging to the trichothecene biosynthetic gene cluster were compared at the transcriptional level between two NIV-producing F. asiaticum and four DON-producing F. graminearum strains. Chemical analysis revealed that time-course toxin production patterns over 14 days did not differ between NIV and DON strains, excluding F. asiaticum R308, which was a low NIV producer. Both quantitative real-time polymerase chain reaction and Northern analysis revealed that the majority of TRI gene transcripts peaked at day 2 in both NIV and DON producers, which is 2 days earlier than trichothecene accumulation in liquid medium. Comparison of the gene expression profiles identified an NIV-specific pattern in two transcription factor-encoding TRI genes (TRI6 and TRI10) and TRI101, which showed two gene expression peaks during both the early and late incubation periods. In addition, the amount of trichothecenes produced by both DON and NIV producers were correlated with the expression levels of TRI genes, regardless of the trichothecene chemotypes. Therefore, the reduced production of NIV by R308 compared to NIV or DON by the other strains may be attributable to the significantly lower expression levels of the TRI genes, which showed early expression patterns.

• Journal of Microbiology and Biotechnology
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• 제2권4호
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• pp.278-283
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• 1992

Aldehyde production by cells of a methanol utilizing yeast, Hansenula nonfermentans KYP-1 was improved when they were grown in a methanol-limited continuous culture, in comparison with cells grown in a batch culture. A higher cell yield was also obtained in continuous culture than in batch culture. This could be due to the fact that a lower methanol concentration was maintained in the jar fermentor to minimize growth inhibition by methanol. A maximum cell productivity of 0.219 g.$liter^{-1}.hr^{-l}$ and a cell yield of 47% were obtained at dilution rates of 0.1 $hr{-1}$ and 0.06 hr{-1}, respectively. The greatest amount of aldehyde was measured at a dilution rate of 0.08 $hr{-1}$. Under optimum reaction conditions, 915.7 mM of acetaldehyde was produced from 1.5 M ethanol after 21 hours reaction, with a conversion rate of 61%. Propionaldehyde and acrolein were produced with conversion rates of 32.7% and 44%, respectively.

• 미생물과산업
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• 제27권1호
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• pp.23-32
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• 2001

• Asian-Australasian Journal of Animal Sciences
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• 제22권2호
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• pp.201-205
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• 2009

Effects of Cordyceps militaris mycelia on rumen microbial fermentation were determined by measuring in vitro gas production, cellulose digestion and VFA concentrations. C. militaris mycelia was added to buffered rumen fluid with final concentrations of 0.00, 0.10, 0.15, 0.20, 0.25 and 0.30 g/L and incubation times were for 3, 6, 9, 12, 24, 36, 48 and 72 h. At all incubation times, the gas production showed a quadratic increase with the supplementation of C. militaris mycelia; maximum responses were seen with 0.25 g/L supplementation. However, the gas production was significantly lower for the 0.30 g/L supplementation than for the 0.25 g/L supplementation from 9 h to 72 h incubation. The cellulose filter paper (FP) digestion showed a quadratic increase, as did the gas production except at 3 h incubation. The concentration of total VFA was significantly increased by the supplementation of C. militaris mycelia compared with the control treatment; the highest response was also seen with 0.25 g/L supplementation. This was true for responses in the concentration of acetic and propionic acids. As opposed to other responses, the responses of pH to the supplementation of C. militaris mycelia showed a quadratic decrease from 3 h to 36 h incubation. In conclusion, C. militaris mycelia alter the mixed rumen microbial fermentation with increases in the production of gas and VFA, and cellulose FP digestion.

• Asian-Australasian Journal of Animal Sciences
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• 제17권6호
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• pp.877-884
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• 2004

Although gut microbial functions have been analyzed through cultivation of isolated microbes, molecular analysis without cultivation is becoming a popular approach in recent years. Gene cloning studies have partially revealed the mechanisms involved in fiber digestion of individual microbe. The molecular approach finally made it possible to analyze full genomes of the representative rumen cellulolytic bacteria Fibrobacter and Ruminococcus. The coming database may contain useful information such as regulation of gene expression relating to fiber digestion. Meanwhile, unculturable bacteria are still poorly characterized, even though they are main constituents of gut microbial ecosystem. The molecular analysis is essential to initiating the studies on these unculturable bacteria. The studies dealing with rumen and large intestine are revealing considerable complexity of the microbial ecosystems with many undescribed bacteria. These bacteria are being highlighted as possibly functional members contributing to feed digestion. Manipulation of gut bacteria and gut ecology for improving animal production is still at challenging stage. Bacteria newly introduced in the rumen, whether they are genetically modified or not, suffer from poor survival. In one of these attempts, Butyrivibrio fibrisolvens expressing a foreign dehalogenase was successfully established in sheep rumen to prevent fluoroacetate poisoning. This expands choice of forages in tropics, since many tropic plants are known to contain the toxic fluoroacetate. This example may promise the possible application of molecular breeding of gut bacteria to the host animals with significance in their health and nutrition. When inoculation strategies for such foreign bacteria are considered, it is obvious that we should have more detailed information of the gut microbial ecology.

• 한국수소및신에너지학회논문집
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• 제26권3호
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• pp.247-259
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• 2015

This study was performed to investigate the application of dark $H_2$ fermentation to two-stage bioprocesses for organic waste treatment and energy production. We reviewed information about the two-stage bioprocesses combining dark $H_2$ fermentation with $CH_4$ fermentation, photo $H_2$ fermentation, microbial fuel cells (MFCs), or microbial electrolysis cells (MECs) by using academic information databases and university libraries. Dark fermentative bacteria use organic waste as the sole source of electrons and energy, converting it into $H_2$. The reactions related to dark $H_2$ fermentation are rapid and do not require sunlight, making them useful for treating organic waste. However, the degradation is not complete and organic acids remain. Thus, dark $H_2$ fermentation should be combined with a post-treatment process, such as $CH_4$ fermentation, photo $H_2$ fermentation, MFCs, or MECs. So far, dark $H_2$ fermentation followed by $CH_4$ fermentation is a promising two-stage bioprocess among them. However, if the problems of manufacturing expenses, operational cost, scale-up, and practical applications will be solved, the two-stage bioprocesses combining dark $H_2$ fermentation with photo $H_2$ fermentation, MFCs, or MECs have also infinite potential in organic waste treatment and energy production. This paper demonstrated the feasibility of two-stage bioprocesses combining dark $H_2$ fermentation as a novel system for organic waste treatment and energy production.

• Animal Bioscience
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• 제36권9호
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• pp.1384-1392
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• 2023

Objective: Replacing soybean meal (SBM) with cricket (Gryllus bimaculatus) meal pellets (CMP) in concentrate diets was investigated for feed efficiency, ruminal fermentation and microbial protein synthesis in Thai native beef cattle. Methods: Four male beef cattle were randomly assigned to treatments using a 4×4 Latin square design with four levels of SBM replaced by CMP at 0%, 33%, 67%, and 100% in concentrate diets. Results: Results revealed that replacement of SBM with CMP did not affect dry matter (DM) consumption, while digestibilities of crude protein, acid detergent fiber and neutral detergent fiber were significantly enhanced (p<0.05) but did not alter digestibility of DM and organic matter. Increasing levels of CMP up to 100% in concentrate diets increased ruminal ammoniacal nitrogen (NH₃-N) concentrations, blood urea nitrogen, total volatile fatty acids and propionate concentration (p<0.05), whereas production of methane and protozoal populations decreased (p<0.05). Efficiency of microbial nitrogen protein synthesis increased when SBM was replaced with CMP. Conclusion: Substitution of SBM with CMP in the feed concentrate mixture at up to 100% resulted in enhanced nutrient digestibility and rumen fermentation efficiency, with increased volatile fatty acids production, especially propionate and microbial protein synthesis, while decreasing protozoal populations and mitigating rumen methane production in Thai native beef cattle fed a rice straw-based diet.