• Journal of Microbiology and Biotechnology
• /
• v.22 no.1
• /
• pp.84-91
• /
• 2012

Two staphylococcal lipases were obtained from Staphylococcus epidermidis S2 and Staphylococcus aureus S11 isolated from sebaceous areas on the skin of the human face. The molecular mass of both enzymes was estimated to be 45 kDa by SDS-PAGE. S2 lipase displayed its highest activity in the hydrolysis of olive oil at $32^{\circ}C$ and pH 8, whereas S11 lipase showed optimal activity at $31^{\circ}C$ and pH 8.5. The S2 lipase showed the property of cold-adaptation, with activation energy of 6.52 kcal/mol. In contrast, S11 lipase's activation energy, at 21 kcal/mol, was more characteristic of mesophilic lipases. S2 lipase was stable up to $45^{\circ}C$ and within the pH range from 5 to 9, whereas S11 lipase was stable up to $50^{\circ}C$ and from pH 6 to 10. Both enzymes had high activity against tributyrin, waste soybean oil, and fish oil. Sequence analysis of the S2 lipase gene showed an open reading frame of 2,067 bp encoding a signal peptide (35 aa), a pro-peptide (267 aa), and a mature enzyme (386 aa); the S11 lipase gene, at 2,076 bp, also encoded a signal peptide (37 aa), pro-peptide (255 aa), and mature enzyme (399 aa). The two enzymes maintained amino acid sequence identity of 98-99% with other similar staphylococcal lipases. Their microbial origins and biochemical properties may make these staphylococcal lipases isolated from facial sebaceous skin suitable for use as catalysts in the cosmetic, medicinal, food, or detergent industries.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.4
• /
• pp.624-630
• /
• 2008

Terminal restriction fragment length polymorphism (T-RFLP) is a method that has been frequently used to survey the microbial diversity of environmental samples and to monitor changes in microbial communities. T-RFLP is a highly sensitive and reproducible procedure that combines a PCR with a labeled primer, restriction digestion of the amplified DNA, and separation of the terminal restriction fragment (T-RF). The reliable identification of T-RF requires the information of nucleotide sequences as well as the size of T-RF. However, it is difficult to obtain the information of nucleotide sequences because the T-RFs are fragmented and lack a priming site of 3'-end for efficient cloning and sequence analysis. Here, we improved on the T-RFLP method in order to analyze the nucleotide sequences of the distinct T-RFs. The first method is to selectively amplify the portion of T-RF ligated with specific oligonucleotide adapters. In the second method, the termini of T-RFs were tailed with deoxynucleotides using terminal deoxynucleotidyl transferase (TdT) and amplified by a second round of PCR. The major T-RFs generated from reference strains and from T-RFLP profiles of activated sludge samples were efficiently isolated and identified by using two modified T-RFLP methods. These methods are less time consuming and labor-intensive when compared with other methods. The T-RFLP method using TdT has the advantages of being a simple process and having no limit of restriction enzymes. Our results suggest that these methods could be useful tools for the taxonomic interpretation of T-RFs.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.4
• /
• pp.397-402
• /
• 2009

Kombucha tea(KT) is sugared black tea fermented with a symbiotic culture of acetic acid bacteria and yeasts, which is said to be tea fungus. KT is claimed to have various beneficial effects on human health, but there is very little scientific evidence available in the literature. In the present study, KT along with black tea(BT) and black tea manufactured with tea fungus enzymes(enzyme-processed tea, ET) were evaluated for hepatoprotective and curative properties against $CCl_4$-induced toxicity, using male albino rats as an experimental model by analyzing aspartate transaminase, alanine transaminase, and alkaline phosphatase in plasma and malondialdehyde content in plasma and liver tissues. Histopathological analysis of liver tissue was also included. Results showed that BT, ET, and KT have the potential to revert the $CCl_4$-induced hepatotoxicity. Among the three types of teas tried, KT was found to be more efficient than BT and ET. Antioxidant molecules produced during the fermentation period could be the reason for the efficient hepatoprotective and curative properties of KT against $CCl_4$-induced hepatotoxicity.

• Journal of Applied Biological Chemistry
• /
• v.57 no.4
• /
• pp.313-320
• /
• 2014

Black liquor (BL) is a by-product of rice straw pulping process. It is a low costs raw material for production value-adding proteins and enzymes, which has been paid more and more attention to reduce its environmental pollution. Mixed cultures of micelial fungi, Trichoderma reesei Northern Regional Research Laboratory (NRRL)11236, Trichoderma reesei NRRL 6165 and Aspergillus niger strains NRC 5A, NRC 7A, and NRC 9A were evaluated for their ability to produce xylanase using crude hemicellulose (CHC) prepared from BL and peat moss as an inert support under solid state fermentation (SSF). The most potent strains, A. niger NRC 9A (818.26 U/g CHC) and T. reesei NRRL 6165 ($100.9{\pm}57.14$ U/g CHC), were used in a mixed culture to enhance xylanase production by co-culturing under SSF. In the mixed culture, xylanase production ($1070.52{\pm}12.57$ U/g CHC) was nearly1.3 and 10.6-fold increases over the activities attained in their monocultures, A. niger NRC 9A and T. reesei NRRL 6165, respectively. Optimization of the culture parameters of the mixed culture SSF process, concentration of ammonium sulfate and corn steep liquor, CHC/peat moss ratio, inoculum size and ratios of the two strains, initial pH value, initial moisture content and incubation time, exhibited a significant increase ($2414.98{\pm}84.02$ U/g CHC) in xylanase production than before optimization.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.3
• /
• pp.408-413
• /
• 2006

A strain, P821, with phospholipase D activity was isolated from soil and identified as a Streptomyces species. The phospholipase D enzyme was purified from a culture broth of the isolated strain using ammonium sulfate precipitation and DEAE-Sepharose, phenyl-Sepharose, and Superose 12 HR column chromatographies. The purified enzyme exhibited an optimum temperature and pH of $55^{\circ}C$ and 6.0, respectively, in the hydrolysis of phosphatidylcholine and remained stable up to $60^{\circ}C$ within a pH range of 3.5-8.0. The enzyme also catalyzed a transphosphatidylation reaction to produce phosphatidylserine with phosphatidylcholine and serine substrates. The optimum conditions for the transphosphatidylation were $30^{\circ}C$ and pH 5.0, indicating quite different optimum conditions for the hydrolysis and transphosphatidylation reactions. The gene encoding the enzyme was cloned by Southern hybridization and colony hybridization using a DNA probe designed from the conserved regions of other known phospholipase D enzymes. The resulting amino acid sequence was most similar to that of the PLD enzyme from Streptomyces halstedii (89.5%). Therefore, the enzyme was confirmed to be a phospholipase D with potential use in the production of phosphatidylserine.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.6
• /
• pp.1011-1017
• /
• 2001

Streptomyces sp. Y-110 cytochrome P-450, induced by the addition of compactin -Na into the culture medium, was purified from the cell extract to apparent homogeniety, mainly by DEAE-Sepharose, hydroxyapatite, and Mono Q column chromatyography. The sepcific activity of purified enzyme on its substrate, compactin-Na, was determined to be 15 nmol of pravastatin per mg protein. The molecular mass of this enzyme on SDS-PAGE was $37{\pm}0.5$ kDa, pI was 4.5, and its CO difference spectrum showed maximum absorption peaks at 452 and 550nm, respectively. The N-terminal amino acid sequence was determined to be Met>Thr>Cys>Thr>Pro>Val>Thr>Val>The>Gly>Ala>Ala>Gly>Gln>Ile>Gly>Tyr>Ala>Leu. Its apparent $K_m$ on compactin-Na was $1.294{\mu}M{\cdot}min^-1,\;and\;V_{max}\;was\;1.028{\mu}M{\cdot}min^-1$. The maximum substrate concentration ($K_s$) for reaction was $270 {\mu}M$and thus $1/[K_s]$ was $3.7{\mu}M$. These physicochemical characteristics and kinetic behavior of this enzyme were compared and shown to be different from those of Streptomyces cytochrome P-450 enzymes reported, suggesting that this enzyme may be an additional member of the Streptomyces cytochrome P-450 family.

• Journal of Environmental Science International
• /
• v.27 no.9
• /
• pp.771-780
• /
• 2018

To develope a microbial weed control agent, HCN-producing bacteria were isolated, and their characteristics were investigated. A selected strain of WA15 was identified as Pseudomonas koreensis by morphological, cultural, biochemical and 16S rRNA gene analyses. The conditions for HCN production was investigated by a One-Variable-at-a-Time (OVT) method. The optimal HCN production conditions were tryptone 1%, glycine 0.06%, NaCl 1%, and an initial pH and temperature of 5.0 and $30^{\circ}C$, respectively. The major component for HCN production was glycine. Under optimal conditions, HCN production was about 3 times higher than that of the basal medium. The WA15 strain had physiological activities, such as indoleacetic acid that was associated with the elongation of plant roots and siderophore and ammonification inhibiting fungal growth, and produced hydrolytic enzymes, such as cellulase, pectinase and lipase. The strain was able to inhibit the growth of phytopathogenic fungi, such as Rhizoctonia solani, Botrytis cinerea and Fusarium oxysporum, by the synergistic action of volatile HCN and diffusible antimicrobial compounds. A microscopic observation of R. solani that was teated with the WA15 strain showed morphological abnormalities of fungal mycelia, which could explain the role of the antimicrobial metabolites that were produced by the WA15 strain. The volatile HCN produced by the WA15 strain was also found to have insecticidal activity against termites. Our results indicate that Pseudomonas koreensis WA15 can be applied as a microbial agent for weed control and also as a termite repellent. Furthermore, it could be applied as a microbial termiticidal agent to replace synthetic insecticides.

• Korean Journal of Food Science and Technology
• /
• v.28 no.5
• /
• pp.974-980
• /
• 1996

A biosensor was prepared with dual cathode electrode and immobilized enzyme membrane. A nylon net was used for the immobilization of glucose oxidase and alcohol oxidase. The immobilized enzymes were placed on the surface of the electrode which was prepared with one anode and two cathodes as an oxygen electrode. The determination of components by the biosensor was based on the consumption of dissolved oxygen. The optimum condition of this system was 0.1 M potassium phosphate buffer solution, pH 7.5 at $35^{\circ}C$. Glucose and ethanol in takju were simultaneously determined by the biosensor. Comparing with UV-spectrophotometer and gas chromatograph for cross checking, there was a good correlation between the biosensor and the conventional methods. Biosensor with dual cathode electrode required no clarification or pretreatments. It was used for simultaneous determination of glucose and ethanol during the fermentation of takju.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.245-245
• /
• 2017

Heavy metal pollution of agricultural soils affects land productivity and has impact on the quality of surrounding ecosystem. Soil microbial community parameters are used as reliable indices for assessing quality of agricultural lands under metal stress. This study investigated bacterial community structure of polluted and undisturbed paddy soils to elucidate soil factors that are related to alteration of bacterial communities under conditions of metal pollution. No obvious differences in the richness or diversity of bacterial communities were observed between samples from polluted and control areas. The bacterial communities of three locations were distinct from one another, and each location possessed distinctive set of bacterial phylotypes. The abundances of several phyla and genera differed significantly between study locations. Variation of bacterial community was mostly related to soil general properties at phylum level while at finer taxonomic levels concentrations of arsenic and lead were significant factors. According to results of bacterial community functional prediction, the soil bacterial communities of metal polluted locations were characterized by more abundant DNA replication and repair, translation, transcription and nucleotide metabolism pathway enzymes while amino acid and lipid metabolism as well as xenobiotic biodegradation potential was reduced.Our results suggest that the soil microbial communities had adapted to the elevated metal concentrations in the polluted soils as evidenced by changes in relative abundances of particular groups of microorganisms at different taxonomic resolution levels, and by altered functional potential of the microbial communities.

• Journal of Animal Environmental Science
• /
• v.2 no.2
• /
• pp.135-145
• /
• 1996

This study was carried out to investigate changes of physico-chemical properties and microbial activity during the early stage of composting with pig and chicken manure. The results were as follows; 1. The temperature was rapidly increased from the 3rd to the 7th day, and especially the pig manure compost preparing with enzyme was maintained $56^{\circ}C{\sim}69^{\circ}C$. 2. The pH range was shown $7.7{\sim}9.3$, and the pH level increased from the 3rd day to 25th day. Also after the 25th day the pH level decreased gradually. 3. The C/N ratio in the pig manure compost decreased 16.8 at the 30th day, while the compost containing enzymes decreased 19.2 at the 30th day. Chicken manure compost showed similar results at the 28 of C/N ratio at the 30th day with enzyme treatment. 4. The total ammount of sugar in pig manure compost was $6,000{\sim}7,000mg/kg$, while the chicken manure compost was $2,000{\sim}4,000mg/kg$. However, there was no significant difference in view point of enzyme treatment. 5. Cellulase, phosphatase and xylanase activity were continually increased, however amylase and urease activity were not changed during composting.