• Journal of Microbiology and Biotechnology
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• 제29권12호
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• pp.1957-1968
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• 2019

Tetraselmis is a green algal genus, some of whose species are important in aquaculture as well as biotechnology. In algal culture, fluorescent lamps, traditional light source for culturing algae, are now being replaced by a cost-effective light-emitting diodes (LEDs). In this study, we investigated the effect of LED light of different wavelengths (white, red, yellow, and blue) on the growth of Tetraselmis suecica and its associated microbial community structures using the next-generation sequencing (NGS). The fastest growth rate of T. suecica was shown in the red light, whereas the slowest was in yellow. The highest OTUs (3426) were identified on day 0, whereas the lowest ones (308) were found on day 15 under red light. The top 100 OTUs associated with day 0 and day 5 cultures of T. suecica under the red and yellow LED were compared. Only 26 OTUs were commonly identified among four samples. The highest numbers of unique OTUs were identified at day 0, indicating the high degree of initial microbial diversity of the T. suecica inoculum. The red light-unique OTUs occupied 34.98%, whereas the yellow-specific OTUs accounted for only 2.2%. This result suggested a higher degree of interaction in T. suecica culture under the red light, where stronger photosynthesis occurs. Apparently, the microbial community associated with T. suecica related to the oxygen produced by algal photosynthesis. This result may expand our knowledge about the algae-bacteria consortia, which would be useful for various biotechnological applications including wastewater treatment, bioremediation, and sustainable aquaculture.

• 한국식품위생안전성학회지
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• 제30권1호
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• pp.65-73
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• 2015

The purpose of this study is to evaluate quality characteristics of the Cheonggukjang produced using rice straw-derived Bacillus cereus free starter culture (RiBS1). The Cheonggukjang was prepared in 0.1 and 1.0% inoculum concentrations of starter culture and fermented from 12 hr to 72 hr at 40 and $50^{\circ}C$. Amino-nitrogen contents after 48 hr fermentation were 559.6~590.2 mg% and 393.8~494.0 mg% at 40 and $50^{\circ}C$, respectively. Sensory evaluation showed that the Cheonggukjang fermented using RiBS1 starter for 48 hr at $50^{\circ}C$ was better than the control. And we inspected on B. cereus and biogenic amine in the Cheonggukjang produced using RiBS1 starter. As a results, B. cereus was not detected and histamine and tyramine of biogenic amine were $5.53{\pm}0.13{\sim}39.96{\pm}0.62mg/kg$. This research results showed that rice straw-derived B. cereus free starter culture (RiBS1) will be produce the Cheonggukjang with good flavour and taste.

• Journal of Microbiology
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• 제44권4호
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• pp.403-408
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• 2006

The purpose of this study was to determine the efficacy of a nucleic acid sequence-based amplification (NASBA) method of detecting noroviruses in artificially and naturally contaminated shellfish. We used 58 fecal samples that tested positive for noroviruses with electron microscopy (EM) to develop an NASBA assay for these viruses. Oligonucleotide primers targeting the polymerase coding region were used to amplify the viral RNA in an isothermal process that resulted in the accumulation of RNA amplicons. These amplicons were detected by hybridization with digoxigenin-labeled oligonucleotide probes that were highly specific for genogroup I (GI) and genogroup II (GII) of noroviruses. The expected band of 327bp appeared in denaturing agarose gel without any nonspecific band. The specific signal for each amplicon was obtained through Northern blotting in many repeats. All fecal samples of which 46(79.3%) belonged to GII and 12(20.6%) belonged to GI were positive for noroviruses by EM and by NASBA. Target RNA concentrations as low as 5pg/ml were detected in fecal specimens using NASBA. When the assay was applied to artificially contaminated shellfish, the sensitivity to nucleic acid was 100pg/1.5g shellfish tissue. The potential use of this assay was also confirmed in naturally contaminated shellfish collected from different ponds in Guangzhou city of China, of which 24 (18.76%) out of 128 samples were positive for noroviruses; of these, 19 (79.6%) belonged to GII and 5 (20.4%) belonged to GI. The NASBA assay provided a more rapid and efficient way of detecting noroviruses in fecal samples and demonstrated its potential for detecting noroviruses in food and environmental samples with high specificity and sensitivity.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.326-329
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• 2003

When an electrokinetic process is applied to a HOC-contaminated soil, hybrid types combined with soil flushing, chemical oxidation, and bioremediation are generally used. Especially when the electrokinetic process is combined with bioremediation, the hybrid technology can solve several limits of bioremediation such as low microbial mobility, low soil temperature, and shortage of nutrients in subsurface circumstance. Because microbial surface is charged negatively, the microorganism moves from cathode to anode under electrical field. In this study, mixed culture mainly-consisted by Pseudomonas sp. was applied to remediate pentadecane-contaminated kaolinite with particle size less than 300${\mu}{\textrm}{m}$. This remediation system was named ‘electrokinetic bioaugmentation’ and consisted of model aquifer, electrode reservoirs, bioreactor, power supply, and pump. The mixed culture above 0.5 of optical density in bioreactor was supplied to two reservoirs and penetrated soil when the electric current was applied. To enhance the removal efficiency, the optimal medium composition, electric current, and voltage were investigated.

• Archives of Pharmacal Research
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• 제11권1호
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• pp.61-64
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• 1988

To investigate the antibiotic constituents of Korean basidiomycetes the carpophores of the wood-rotting basidiomycetes were collected from several locations of Korea, and from them 17 mycelial strains were isolated on potato-dextrose-agar plates supplemented with tetracycline ($20\;{\mu}g/m{\ell}$. The isolated strains were shake-cultured in glucosepeptone-yeast extract medium and then the antibacterial activities of the culture filtrates were assessed by disc-plate method. Among them, 12 strains (70.6%) were active, and basidiomycete strain LMCB-109 (Daedalea quercina) and LMCB-116 showed potent activities against all the six bacterial target organisms including Serratia marcescens.

• Genomics & Informatics
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• 제7권1호
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• pp.41-45
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• 2009

The Korean Agricultural Culture Collection (KACC) has developed a web-based system to provide an integrated database with information updates about microbial resources. This integrated database consists of 5 major functions and contains general information, which includes identification numbers, culture media composition, image information, DNA sequences, patent information, and general forms for ordering and depositing microorganisms. In 2008, KACC started providing characterization information. KACC maintains 9,801 cultures of microorganisms, including 3,296 strains of bacteria, 4,734 fungi, 784 actinomycetes, 64 yeasts, and 923 others.

• Asian-Australasian Journal of Animal Sciences
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• 제18권3호
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• pp.326-331
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• 2005

A rumen simulated continuous culture (RSCC) system was used to study the influence of supplementation of the three different types of protein sources such as urea, casein and soy protein on rumen microbial synthesis in terms of rumen microbial synchronization. The urea treatment showed the highest pH value. Ammonia nitrogen concentration was rapidly increased after feeding and not significantly different in the urea treatment (13.53 mg/100 ml). Protozoa numbers were not significantly different for soy protein and casein treatment compared to urea treatments during incubation. The average concentration of total VFA (mMol) was not detected with significant difference among treatments, but iso-butyrate production showed the highest for soy protein treatment among treatments (p<0.001). The lowest concentration in total iso-acids (iso-butyrate and iso-valerate) production was observed in urea treatment. The soy protein treatment showed no significantly change in acetate/propionate. The amounts of dry matter (DM) out flow showed no significant difference among treatments. Organic matter (OM) flow was the highest for urea treatments and the lowest for casein treatment (p<0.03). The nitrogen flow for casein treatment was not significantly different from other treatments. The efficiency of microbial protein synthesis in terms of microbial nitrogen (MN) synthesis (g MN/kg ADOM) digested in the rumen was highest for casein treatment (58.53 g MN/kg ADOM) compared to soy protein and urea (p<0.05). This result suggests that rumen ammonia releasing rate may influence on microbial protein synthesis in the rumen.

• Journal of Applied Biological Chemistry
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• 제57권4호
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• pp.313-320
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• 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.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2006년도 추계학술대회 및 정기총회
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• pp.7-9
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• 2006

• Natural Product Sciences
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• 제26권3호
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• pp.183-190
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• 2020

Genome mining has recently emerged as a powerful strategy to discover novel microbial secondary metabolites. However, more than 50% of biosynthetic gene clusters are not transcribed under standardized laboratory culture condition. Several methods have been applied to activate silent biosynthetic gene clusters in the microbes so far. Among the regulatory systems for production of secondary metabolites, global regulators, which affect transcription of genes through regulatory cascades, typically govern the production of small molecules. In this review, global regulators to affect production of microbial secondary metabolites were discussed.