• Food Science of Animal Resources
• /
• v.33 no.4
• /
• pp.522-530
• /
• 2013

The ability of probiotics to adhere to the intestinal epithelium likely plays an important role in their colonization of the gastrointestinal tract. Here, we performed high-throughput screening (HTS) for suitable characteristics of potential probiotic bacteria using attachment and colonization ability through a C. elegans surrogate in vivo model. A total of 100 strains of lactic acid bacteria (LAB) isolated from infant feces were subjected to the colonization assay using C. elegans intestine. Based on colonization ability, we showed that nine isolates have a high attachment ability during whole experimental periods (up to 168 h), compared to Lactobacillus rhamnosus strain GG as a control. Also, through the use of an in vitro cell attachment model, nine isolates revealed highly binding activity to the mucus layer. Next, the selected 9 isolates were assayed for their survival ability when exposed to acidic and bile conditions as well as cholesterol reduction and the utilization of prebiotic substrates. As a result, the isolated nine strains were determined to be highly resistant to acid and bile conditions. In addition, they have significant activity for the reduction of cholesterol and utilization of several prebiotic substrates as a carbon source. Finally, the selected nine strains were identified by either L. rhamnosus or L. plantarum (4 strains for L. rhamnosus and 5 strains for L. plantarum, respectively). Taken together, we propose that the direct colonization of probiotics using C. elegans may be applicable to the rapid screening of valuable probiotic strains in vivo.

• Microbiology and Biotechnology Letters
• /
• v.13 no.1
• /
• pp.71-77
• /
• 1985

A bacterium which grows on cyclohexanol as sole carbon and energy source was isolated from sludge of industrial areas in Taegu and identified as Acinetobacter calcoaceticus C-15. The growth medium for the optimal culture condition was composed of 0.2% cyclohexanol, 0.11% $NH_4Cl$, 0.05% $KH_2PO_4$, 0.2% $K_2HPO_4$, 0.02% $MgSO_4{\cdot}7H_2O$, and 0.05% yeast extracts. The optimal pH value and temperature for the growth were 7.2 and $33^{\circ}C$, respectively. Specific growth rate of A. calcoaceticus C-15 at $33^{\circ}C$ on the cyclohexanol and cyclohexanone was $0.27hr^{-1}$ and $0.15hr^{-1}$, respectively. Growth yield for cyclohexanol was 1.0. The bacteria utilized ethanol, 1-butanol, 1-pentanol, and cyclohexanol as a carbon source but not methanol, 1-hexanol, m-cresol, glycerol, and cyclohexane. The bacteria grew on benzoate, adipate, acetate, and citrate, but did not on salicylate, phthalate, p-hydroxybenzoate, and gluconate. A calcoaceticus C-15 did not utilize all kind of sugars other than xylose. Cell-free extracts contained $NAD^+$-linked cyclohexanol dehydrogenase which catalized the oxidation of cyclohexanol to cyclohexanone.

• Journal of Microbiology and Biotechnology
• /
• v.15 no.3
• /
• pp.616-625
• /
• 2005

It is likely that maltose could provide a good substrate for the bacteria in the intestine, when the pathogenic bacteria invade and colonize in human gut. For better understanding of this organism's maltose metabolism, a mutant that was not able to grow with maltose as a sole carbon source was screened from a library of mutants constructed by a random transposon mutagenesis. By a transposon-tagging method, malPQ genes encoding a maltodextrin phosphorylase and a 4-${\alpha}$-glucanotransferase, were identified and cloned from Vibrio vulnificus. The deduced amino acid sequences of malPQ from V. vulnificus were 48 to $91\%$ similar to those of MalP and MalQ reported from other Enterobacteriaceae. Functions of malPQ genes were assessed by the construction of mutants whose malPQ genes were inactivated by allelic exchanges. When maltose was used as the sole carbon source, neither malP nor malQ mutant was able to grow to a substantial level, revealing that the MalP and MalQ are the only enzymes for metabolic utilization of maltose. The malQ mutant exhibited decreased adherence toward intestinal epithelial cells in vitro, but there was no difference in the $LD_{50}s$ of the wild-type and the malQ mutant in mice. Therefore, it appears that MalQ is less important in the pathogenesis of V. vulnificus than would have been predicted by considering maltose as a most common sugar in the intestine, but not completely dispensable for virulence in mice.

• Microbiology and Biotechnology Letters
• /
• v.13 no.4
• /
• pp.397-402
• /
• 1985

The fermentation of various sugars by C. thermosaccharolyticum was examined under pH controlled, anaerobic condition. The kinetic model for Product formation at various sugars was the combination of growth and non-growth associated mode. In the utilization of a single sugar, glucose was the best carbon source for growth. The specific growth rate of glucose, xylose and cellobiose were 0.363 h$^{-1}$, 0.242 h$^{-1}$ and 0.144 h$^{-1}$ respectively. The production of ethanol from glucose showed a negatively growth associated mode, so the higher growth rate decreased the productivity of ethanol. The maximum concentrations of the produced ethanol were 2.42 g/l, 3.76 g/l, and 3.4 g/l on glucose, xylose, and cellobiose. No glucose was detected during cellobiose fermentation. Sequential utilization of sugars was observed in the mixtures of glucose, xylose and cellobiose. It preferred glucose, followed by xylose and then cellobiose. The presence of other sugars had little or no effect on the rate of another sugar utilization. Cell lysis at the end of fermentation occured more slowly in the mixtures of sugars than a single sugar.

• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.101-101
• /
• 2010

Anaerobic digestion(AD) is the most promising method for treating and recycling of different organic wastes, such as organic fraction of municipal solid waste, household wastes, animal manure, agro-industrial wastes, industrial organic wastes and sewage sludge. During AD, i.e. organic materials are decomposed by anaerobic forming bacteria and fina1ly converted to excellent fertilizer and biogas which is a mixture of carbon dioxide and methane. AD has been one of the leading technologies that can make a large contribution to produce renewable energy and to reduce $CO_2$ and other green-house gas(GHG) emission, it is becoming a key method for both waste treatment and recovery of a renewable fuel and other valuable co-products. Currently some 80% of the world's overall energy supply of about 400 EJ per year in derived from fossil fuels. Nevertheless roughly 10~15% of this demand is covered by biomass resources, making biomass by far the most important renewable energy source used to date. The representative biofuels produced from the biomass are bioethanol, biodiesel and biogas, and currently biogas plays a smaller than other biofuels but steadily growing role. Traditionally anaerobic digestion applied for different biowaste e.g. sewage sludge, manure, other organic wastes treatment and stabilization, biogas has become a well established energy resource. However, the biowaste are fairly limited in respect to the production and utilization as renewable source, but the plant biomass, the so called "energy crops" are used for more biogas production in EU countries and the investigation on the biomethane potential of different crops and plant materials have been carried out. In Korea, with steadily increasing oil prices and improved environmental regulations, since 2005 anaerobic digestion was again stimulated, especially on the biogasification of different biowastes and agro-industrial biomass including "energy crops". This study have been carried out to investigate anaerobic biodegradability by the biochemical methane potential(BMP) test of animal manures, different forage crops i.e. "energy crops", plant and industrial organic wastes in the condition of thermophilic temperature, The biodegradability of animal manure were 63.2% and 58.2% with $315m^3CH_4/tonVS$ of cattle slurry and $370m^3CH_4/tonVS$ of pig slurry in ultimate methane yields. Those of winter forage crops were the range 75% to 87% with ultimate methane yield of $378m^3CH_4/tonVS$ to $450m^3CH_4/tonVS$ and those of summer forage crops were the range 81% to 85% with ultimate methane yield of $392m^3CH_4/tonVS$ to $415m^3CH_4/tonVS$. The forge crops as "energy crops" could be used as good renewable energy source to increase methane production and to improve biodegradability in co-digestion with animal manure or only energy crop digestion.

• Korean Journal of Organic Agriculture
• /
• v.26 no.3
• /
• pp.427-437
• /
• 2018

In this study, microorganism community characteristics of organic managed soil which applied rye (Secale cereal L.) as green manure for 25 years, were determined. The chemical properties of organic soil showed high level of organic matter and available $P_2O_5$, while the level of exchangeable cation was low. The analysis of dehydrogenase activity and carbon source utilization indicated that the values in on organic soil were significantly higher than those of the control. It suggested that the microorganism community of organic soil had high microorganism activity, compared to the control. In addition, when the 16S rRNA gene-targeted NGS (Next generation sequencing) analysis was conducted to estimate the class of bacterial community, the class level of bacterial taxon composition on organic soil showed higher portion of Sphingobacteriia, Acidobacteriia, Gammaproteobacteria, Solibacteres and Planctomycetia. By base on the results of various reports in which organic managed soil had high portion of Acidobacteriia and Planctomycetia, the characteristic of taxon composition in organic soil, which showed the high percentages of Ktedonobacteria, Sphingobacteriia, Acidobacteriia and Gammaproteobacteria, was resulted from the application of rye as a green manure for the long term. However, further researches were needed because the crop effect was not considered in this study.

• Korean Journal of Microbiology
• /
• v.28 no.1
• /
• pp.71-75
• /
• 1990

The isolates biodigrading crude oil were examined to characterize thier properties. Isolates which were identified as Acinetobacter lwoffii G1, Klebsiella pneumoniae L25, Pseudomonas maltophilia N246, Xanthomonas campestris M12, and Xanthomonas sp. M28. The optimum concentration of crude oil was 0.15% for the bacterial growth. X. campestris M12, Xanthomonas sp. M28, and K. penumoniae L25 showed the maximal growth at the concentration of 3.5% sodium chloride, indicating that they were derived from sea water. Among the isolates, X. campestris M12, Xanthomonas sp. M28 specially utilized hexadecane and octane, and P. maltophilia N246 utilized octane with optimum concentration of 0.2-0.3% as sole carbon source. The utilization of components of saturate fraction by K. pneumoniae L25 was examined by gas-liquid chromatography. The short-chain saturates are used before the long chain ones although they almost disappear within 8 days of incubation at $30^{\circ}C$.

• Microbiology and Biotechnology Letters
• /
• v.27 no.1
• /
• pp.46-53
• /
• 1999

The purpose of this study was to optimize the conditions of continuous mixed culture of C.butyricum and R. spaeroides K-7, which were able to produce hydrogen using biomass-dreived substrate. To investigate the possibility of continuous culture, semi-continuous culture was carried out for 20 days. In semi-continuous culture using the reactor system, the replacement rate of fresh medium was 30% of total medium volume for the highest hydrogen evolution. In continuous culture, the optimum dilution rate was determined to be 0.05$h^{-1}$. The continuous culture produced 3.1 times as compared with the hydrogen on batch culture. On the other hand, the continuous mixed culture produced 1.3~2.1 times as much as hydrogen of the continuous monoculture of C. butyricum. When 10g of glucose in the media (1l) was supplied as a carbon source on continuous culture, mixed culture of C. butyricum and R. sphaeroides K-7 increased hydrogen evolution rate. Because considerable amount of glutamate was contained in waste water of glutamate fermentation, utilization of glutamate was examined in mixed culture. As a result of examination, production of hydorgen was slightly inhibited by high concentration of glutamate, more than 20mM, on continuous monoculture of R. sphaeroides K-7. On the other hand, both on continuous monoculture of C. butyricum and on mixed culture of C. butyricum and R. sphaeroides K-7, production of hydrogen was not inhibited by high concentration of glutamate such as 100mM. Hence this suggests that high concentration of waste water can be used as good substrate for hydrogen production on monoculture of C. butyricum and mixed culture of C. butyricum and R. sphaeroides K-7.

• Microbiology and Biotechnology Letters
• /
• v.6 no.4
• /
• pp.155-159
• /
• 1978

Phenol utilizing yeast No. 558 isolated from soil sewage sediment was able to use substantial amount of phenol as the sole carbon source, and the biomass productivity by this organism was very excellent. This organism could grow well in 1000 ppm of phenol concentration, the maxim-um specific growth rate obtainable at pH 5.0, 3$0^{\circ}C$ was 0.27/hr., and the biomass yield coefficient Y vs. consumed phenol was 3.2. Maximum production rate of biomass was observed at 35$^{\circ}C$, pH 3.5 to pH 4.5, and the addition of the 0.005~0. 01% yeast extract was the most effective. Addition of HgCl$_2$ and phenyl hydrazine, inhibitors of oxide-reductase, in the phenol containing cultural liquid caused this organism no-growth at the concentration of 10$^{-5}$ M, 10$^{-3}$ M respectively. This organism could utilize not only phenol but catechol, resorcinol and benzidine.

• Microbiology and Biotechnology Letters
• /
• v.2 no.1
• /
• pp.1-7
• /
• 1974

For the purpose of producing cellulosic single-cell protein from the agricultural wastes, 172 strains of cellulose-assimilating bacteria were isolated from 102 samples of rotten woods, compost soils, soils and so on by the enrichment culture technique. The isolates were examined for their ability to utilize cellulose as carbon source, and then six strains were screened by their strong cellulose assimilating ability and identified as follows: 1. Among six strains of bacteria screened, five strains were identified as species belonged to the genus Cellulomonas and the remainder to the genus of Sporocytophaga. 2. The isolated Sporocytophaga species was identified as S. ellipsosporn because it has a ellipsoidal microcyst. 3. The isolated Cellulomonas species were identical to a strain of C. fimi, C. aurcgena, C. gelida, respectively and two strains to C. flavigena. 4. The isolated C. aurogena was proved to be a new variety becauuse it has different characteristics of assimilating pentoses such as arabinose and xylose from the strain discribed in Bergey's Manual.