• Asian-Australasian Journal of Animal Sciences
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• v.14 no.1
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• pp.54-60
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• 2001

A study was conducted to assess the nutritive value of two diets based on a low-energy variety of wheat, RAC C1 and their effects on intestinal mucosal structure and function in broiler chickens. The diets were fed with or without microbial enzyme supplement to male and female broiler chickens. The digesta viscosity was reduced (p<0.001) through supplementation with a microbial enzyme in male and female chicks. Enzyme supplementation also improved the dietary apparent metabolizable energy content (p<0.001) and had slight but non-significant positive effects on chick growth and feed conversion ratio. Intestinal mucosal structure and enzyme function were not affected by microbial enzyme supplement. Male chicks consumed more feeds (p<0.001), attained higher final body weight (p<0.001) and were more efficient at feed utilization (p<0.01) than the female chicks. Except for duodenal villus surface area and ileal protein content, intestinal mucosal structure and enzyme activities were similar between the two sexes and dietary treatment groups. The study showed an improvement in the nutritive value of the diets in the presence of the microbial enzyme supplement.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.469-474
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• 1999

Thermoactinomyces sp. E79 produced two types of thermostable alkaline proteases extracellularly. A minor protease was separated from a major protease by using DEAE-column chromatography. This enzyme was purified to homogeneity by ammonium sulfate and DEAE-Sepharose ion-exchange chromatography. The purified minor protease showed different biochemical properties compared to the major protease. The molecular mass of the purified enzyme was estimated by SDS-PAGE to be 36 kDa. Its optimum temperature and pH for proteolytic activity against Hammarsten casein were $70^{\circ}C$ and 9.0, respectively. The enzyme was stable up to$75^{\circ}C$ and in an alkaline pH range of 9.0-11.0. The enzyme was inhibited by phenylmethylsulfonyl fluoride (PMSF) and $Hg^{2+}, indicating that the enzyme may be a cysteine-dependent serine protease. In addition, the enzyme cleaved the endoproteinase substrate, succinyl-Ala-Ala-Pro-Phe-p- nitroanilide, and the $K_m$ value for the substrate was 1.2 mM.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.186-186
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• 2005

• Journal of Microbiology
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• v.44 no.6
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• pp.583-590
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• 2006

In this study, an organic solvent tolerant bacterial strain was isolated. This strain was identified as Pseudomonas sp. strain S5, and was shown to degrade BTEX (Benzene, Toluene, Ethyl-Benzene, and Xylene). Strain S5 generates an organic solvent-tolerant lipase in the late logarithmic phase of growth. Maximum lipase production was exhibited when peptone was utilized as the sole nitrogen source. Addition of any of the selected carbon sources to the medium resulted in a significant reduction of enzyme production. Lower lipase generation was noted when an inorganic nitrogen source was used as the sole nitrogen source. This bacterium hydrolyzed all tested triglycerides and the highest levels of pro-duction were observed when olive oil was used as a natural triglyceride. Basal medium containing Tween 60 enhanced lipase production to the most significant degree. The absence of magnesium ions ($Mg^{2+}$) in the basal medium was also shown to stimulate lipase production. Meanwhile, an alkaline earth metal ion, $Na^+$, was found to stimulate the production of S5 lipase.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.324-324
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• 2005

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.323-323
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• 2005

• Journal of Microbiology
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• v.44 no.3
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• pp.354-359
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• 2006

This study examined the capacity of immobilized bacteria to degrade petroleum hydrocarbons. A mixture of hydrocarbon-degrading bacterial strains was immobilized in alginate and incubated in crude oil-contaminated artificial seawater (ASW). Analysis of hydrocarbon residues following a 30-day incubation period demonstrated that the biodegradation capacity of the microorganisms was not compromised by the immobilization. Removal of n-alkanes was similar in immobilized cells and control cells. To test reusability, the immobilized bacteria were incubated for sequential increments of 30 days. No decline in biodegradation capacity of the immobilized consortium of bacterial cells was noted over its repeated use. We conclude that immobilized hydrocarbon-degrading bacteria represent a promising application in the bioremediation of hydrocarbon-contaminated areas.

• Biotechnology and Bioprocess Engineering:BBE
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• v.9 no.5
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• pp.339-344
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• 2004

A method for synthesizing branched fructo-oligosaccharides (BFOS) with a high concentration of sucrose ($1{\~}3$ M) was developed using levansucrase prepared from Leuconortoc mesenteroides B-1355C. The degree of polymerization of oligosaccharides synthesized according to the present method ranged from 2 to over 15. The synthesized BFOS were stable at a pH ranges of 2 to 4 under $120^{\circ}C$. The percentage of BFOS in the reaction digest was $95.7\%$ (excluding monosaccharides; $4.3\%$ was levan). BFOS reduced the insoluble glucan formation by Streptococcus sobrinus on the surfaces of glass vials or stainless steel wires in the presence of sucrose. They also reduced the growth and acid productions of S, sobrinus. Oligosaccharides can be used as sweeteners for foods such as beverages requiring thermo- and acid-stable properties and 3s potential inhibitors of dental caries.

• Journal of Ginseng Research
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• v.3 no.2
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• pp.144-155
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• 1979

In order to investigate biochemical effects of ginseng saponin on microbial enzyme activity, Aspergillus oryxae-143 and Aspergillus niger-40, which were selected from various sources of samples and were the highest enzyme producing mold strains, were grown in the medium containing various saponin concentration (0mg%, l0mg%, 50mg%, l00mg%, 150mg% and 300mg%). The enzyme activity (amylase, protease) was found most active when the saponin was added in the culture media with the concentration of l0mg%∼l00mg%. But it seemed that the action of microbial enzyme was inhibited by adding more than 300mg% of saponin.

• Journal of Microbiology
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• v.42 no.4
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• pp.267-277
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• 2004

Effects of elevated $CO_2$ on soil microorganisms are known to be mediated by various interactions with plants, for which such effects are relatively poorly documented. In this review, we summarize and syn­thesize results from studies assessing impacts of elevated $CO_2$ on soil ecosystems, focusing primarily on plants and a variety the of microbial processes. The processes considered include changes in microbial biomass of C and N, microbial number, respiration rates, organic matter decomposition, soil enzyme activities, microbial community composition, and functional groups of bacteria mediating trace gas emission such as methane and nitrous oxide. Elevated $CO_2$ in atmosphere may enhance certain micro­bial processes such as $CH_4$ emission from wetlands due to enhanced carbon supply from plants. How­ever, responses of extracellular enzyme activities and microbial community structure are still controversy, because interferences with other factors such as the types of plants, nutrient availabilitial in soil, soil types, analysis methods, and types of $CO_2$ fumigation systems are not fully understood.