• Title/Summary/Keyword: strains G5 and G7H

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Studies on Rhodopesudomonas palustris in Korea (한국산 Rhodopseudomonas palustris에 관한 연구)

  • 김경식;이현순
    • Korean Journal of Microbiology
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    • v.14 no.4
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    • pp.167-175
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    • 1976
  • Twenty one strains of Rhodopseudomonas palustris from 7 different regions in Korea have been isolated and identified on the basis of Bergey's Manual in order to study their regional variation. They can use fructose as carbon source (or hydrogen donor). Capacity to produce molecular hydrogen during photosynthesis was tested using liquid medium, modified by omission of $NH_4Cl$ and addition of L0glutamic acid. As nitrogen source nitrate can be used, and isopropanol can be used as hydrogen donor. their pH ranges are 5.9 - 9.1. Their growth are inhibited in the medium that contains 100 units of penicillin G/ml. as for the growing test in dark aerobic condition, the period needed for adptation is longer than that of Korea strain of Rhodopseudomonas gelatinosa.

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Intergeneric Protoplast Fusion between Rhizopus oryzae and Aspergillus oryzae (Rhizopus oryzae와 Aspergillus oryzae의 속간 원형질체융합)

  • Lee, Soo-Youn;Jung, Sung-Won;Kim, Seong-Han;Lee, Yung-Nok
    • Korean Journal of Microbiology
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    • v.31 no.3
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    • pp.218-223
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    • 1993
  • Conditions for the release and regeneration of protoplasts form Rhizopus oryzae and intergeneric protoplast fusion between Rhizopus oryzae and Aspergillus oryzae were studied. High yields of protoplast fusion between Rhizopus oryzae and Aspergillus oxyzae were studied. High yield of protoplasts from young germilings of R. oryzae were obtained by using lytic enzymes containing chitosanase (3 mg/ml), chitinase (3 mg/ml) and Novozym 234 (5 mg/ml). 0.5M glucose was used as the osmotic stabilizer and optimum pH of buffer was determined to be pH 7.5-8.0. Under these conditions, protoplasts were formed after about 3-4 hrs incubation. Approximately, 1.0%-4.9% of these protoplasts were formed after about 3-4 hrs incubation. Approximately, 1.0%-4.9% of these protoplasts regenerated on solid medium with a soft agar overlay. We have also carried out protoplasts fusion between R. oryzae and A. oryzae and have succeeded in obtaining three types of intergeneric fusants. In these experiments, 35% PEG-4000 and 10 mM CaCl$_{2}$ were used as fsogenic agents, and auxotrophic properties were used as a genetic marker to select fusants. Complementation frequency be protoplasts fusion of A. oxyzae and R. oryzae was 4.4% * 10$^{-5}$ . The fusant strains of the first type were prototrophs showing an Aspergillus type morphology with dark-yellow sporulation, those of the second type were also Apergillus type morphology but showed no sporulation. And the strains of the third type stopped growing when fusion products grown on regeneration minimal medium were transferred to fresh minimal medium. The formation of fusion products was observed by fluorescent vital stains for complementary labelling of protoplats from R. oryzae and A. oryzae. Rhodamine 6G and fluorescein diacetate wer useful complementary vital stains of Rhizopus and Aspergillus protoplasts for visualization of requency and type (dicell, multicell) of fusion.

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Changes of Indicator Microorganisms and Pathogenic Bacteria in Spinach during Cook-Chill Process (시금치의 cook-chill 가공 중 오염지표균 및 병원성세균의 변화)

  • Kim, Hye-Jung;Park, Jae-Kap;Lee, Dong-Sun;Paik, Hyun-Dong
    • Korean Journal of Food Science and Technology
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    • v.34 no.5
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    • pp.927-930
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    • 2002
  • Spinach minimally processed using cook-chill and sous vide techniques was vacuum-packed in low gas permeable plastic film, pasteurized at $70^{\circ}C$ for 2 min, cooled rapidly at $3^{\circ}C$, and stored at 3 and $10^{\circ}C$. Contents of mesophilic bacteria, psychrophilic bacteria, anaerobic bacteria, spore-forming bacteria, total coliforms, yeast and molds, fecal Streptococcus, and Enterobacteriacea were measared to identify the degree of food contamination. Number of mesophilic bacteria, detected at $2.2{\times}10^8\;cfu/g$ in raw spinish, decreased to about $6.0{\times}10^3\;cfu/g$ after cook-chill process. During the storage at 3 or $10^{\circ}C$, levels of mesophilic, psychrophilic and anaerobic bacteria increased, whereas total coliforms, yeast and molds, fecal Streptococcus, and Enterobacteriacea were not detected. Twelve strains of Aeromonas hydphila, Escherichia coli O157:H7, Plesiomonas shigelloides, Pseudomonas aeruginosa, Salmonella spp., Shigella spp., Yersinia enterocolitica, Bacillus cereus, Campylococcus spp., Clostridium perfringens, Listeria monocytogenes, and Staphylococcus aureus were examined for detecting the presence of pathogenic bacteria in spinach. B. cereus and C. perfringens were isolated from raw, washed, and cook-chilled spinach, whereas A. hydrophila was isolated only from washed spinach. S. aureus was isolated from raw and washed spinach, but not from cook-chilled spinach. Other pathogenic organisms were not detected in raw, washed, and cook-chilled spinach.

Isolation and Characterization of Mannanase-Producing Bacillus amyloliquefaciens YJ17 from Spent Mushroom (Flammulina velutipes) Substrates

  • Kim, Hye Soo;Kim, Chul Hwan;Kwon, Hyun Sook;Cho, Soo Jeong
    • Journal of Mushroom
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    • v.14 no.1
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    • pp.21-26
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    • 2016
  • The mannanase-producing bacteria, designated YJ17, was isolated from spent mushroom (Flammulina velutipes) substrates. The isolate YJ17 was a facultative anaerobic and was grown at temperatures ranging from $20^{\circ}C$ to $50^{\circ}C$ with an optimal temperature of $40^{\circ}C$. The DNA G+C content of the YJ17 was 44 mol%. The major fatty acids were anteiso-15:0 (38.9%), 17:0 (7.6%), and iso-15:0 (36.5%). The 16S rRNA gene sequence similarity between the isolate YJ17 and other Bacillus strains was from 98% to 99%. In the phylogenetic analysis based on these sequences, the isolate YJ17 and Bacillus amyloliquefaciens clustered within a group together and separated from other species of Bacillus. Based on the physiological and molecular properties, the isolate YJ17 was classified within the genus Bacillus as B. amyloliquefaciens YJ17. The optimal pH and temperature for mannanase activity of B. amyloliquefaciens YJ17 were pH 7.0 and $50^{\circ}C$, respectively.

Incubation conditions affecting biogenic amines degradation of probiotic lactic acid bacteria (프로바이오틱 유산균의 바이오제닉 아민 분해능에 영향을 미치는 배양 조건)

  • Lim, Eun-Seo
    • Korean Journal of Microbiology
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    • v.53 no.4
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    • pp.273-285
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    • 2017
  • The purpose of this study was to investigate the inhibitory effect of antibacterial substances produced by probiotic lactic acid bacteria (LAB) against biogenic amines-producing bacteria and the influence of culture conditions on the antibacterial activity of bacteriocin and organic acid. The bacteriocin solutions of Lactobacillus plantarum FIL20 (64 AU/ml) and Lactobacillus paracasei FIL31 (128 AU/ml) showed strong antibacterial activity against Serratia marcescens CIH09 and Aeromonas hydrophilia RIH28, respectively. And the lactic acid contents in the cell-free culture supernatants (CFCS) obtained from FIL20 and FIL31 strains were $107.3{\pm}2.7mM$ and $129.5{\pm}4.6mM$, respectively. Therefore, the bacteriocin solution (200 AU/ml) and the CFCS ($200{\mu}l/ml$) produced by L. plantarum FIL20 and L. paracasei FIL31 significantly (P < 0.05) decreased the bacterial numbers and histamine and tyramine production ability of S. marcescens CIH09 and A. hydrophilia RIH28. The amounts of histamine and tyramine produced by the CIH09 strain under conditions of low initial pH (5.0) and incubation temperature ($15^{\circ}C$) was significantly reduced by treatment with bacteriocin solution and CFCS obtained from L. plantarum FIL20. In addition, the bacterial counts and biogenic amines contents of CIH09 strain were significantly decreased (P < 0.05) when sodium chloride (5%) or potassium nitrite (200 mg/g) were mixed with the antibacterial substances of L. plantarum FIL20. Consequently, the bacteriocin and organic acid solution of L. plantarum FIL20 and L. paracasei FIL31 can be used as a biological preservation to effectively control the production of biogenic amines by the application of hurdle technology.

Optimization of cultivation conditions for pullulan production from Aureobasidium pullulans MR by response surface methodology (반응표면분석법을 이용한 Aureobasidium pullulans MR의 풀루란 생산을 위한 배양 조건 최적화)

  • Jo, Hye-Mi;Kim, Ye-Jin;Yoo, Sang-Ho;Kim, Chang-Mu;Kim, KyeWon;Park, Cheon-Seok
    • Korean Journal of Food Science and Technology
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    • v.53 no.2
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    • pp.195-203
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    • 2021
  • Aureobasidium pullulans, a black yeast, produces pullulan, a linear α-glucan composed of maltotriose repeating units linked by α(1→6)-glycosidic linkages. Pullulan can be widely used in food, cosmetic, and biotechnology industries. In this study, we isolated eight strains of A. pullulans from Forsythia koreana, Magnolia kobus DC., Spiraea prunifolia var. simpliciflora, Cornus officinalis, Cerasus, and Hippophae rhamnoides. Among them, A. pullulans MR was selected as the best pullulan producer. The effects of a carbon source, a nitrogen source, and pH on pullulan production were examined. The optimal cultivation conditions for pullulan production by A. pullulans MR were determined by response surface methodology as 15% sucrose, 0.4% soy peptone, and an initial pH of 7 at 26℃. Under these conditions, the predicted pullulan production was 47.6 g/L, which was very close to the experimental data (48.9 g/L).

A Study on the Conversion to Feed Stuff from Cellulosic Biomass (섬유질자원(纖維質資源)의 사료(飼料) 전환(轉換))

  • Lee, Ke-Ho;Sung, Chang-Geun;Chung, Kyu-Ok
    • Applied Biological Chemistry
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    • v.27
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    • pp.29-46
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    • 1984
  • To utilize several species of hard wood as raw materials of feed products, fermentation characteristics of cellulosic substrates to single cell protein was investigated, and results were summarized as follows. Among the microorganisms investigated, Tricoderma viride was selected as one of the most cellulolytic. Mixed culture of fungi did not show a synergistic effect on cellulose degradation. When the fungi were cultured at $28^{\circ}C$ for 7 days in a medium containing wheat bran 25 g, cellulose 0.25 g, proteose peptone 0.025 g and tween 800.025 g, cellulotic activities on carboxy methyl cellulose and filter paper reached maximum at 12 hr. The alkali treatment resulted in increased degradation of substrate from 13 to 18% when treated with enzymes for 12h, and reducing sugar formation increased with decreased size of substrates. Glucose was a very good feedback inhibitor of the enzyme from T.viride than that of xylose. When the substrate was rehydrolyzed, hydrolysis rate was 31% to reducing sugars within 12 hr. Quantative anlysis with HPLC showed the ratio of glucose to xylose in sugar syrups as 1.77 to 1. For the purpose of producing cellulosic-single cell protein from the sawdust of mulberry tree, 15 strains of xylose-assimilating yeast were isolated from 42 samples of rotten woods and compost soils and examined for their ability to utilize xylose. Then three strains were selected by their strong xylose-assimilating activities. The cultivative condition, the growth characteristics, and protein and nucleic acid productivities of three strains were investigated. The results obtained were, 1. Wood hydrolysate of mulberry tree was assimilated by 5 strains of CHS-2, CHS-3, ST-40, CHS-12 and CHS-13. 2. The optimum initial pH and temperature for the growth of strain CHS-13 were 4.4 and $30^{\circ}C$. 3. The specific growth rate of strain CHS-13 was $0.23h^{-1}$ and generation time was 3.01 hrs at the optimum condition. 4. CHS-13 strain assimilated 81 % of sugar in wood hydrolysate. 5. CHS-13 strain was identified as Candida guilliermondii var. guilliermondii 6. When the CHS-13 strain was cultured in the wood hydrolysate containing yeast extract, L-protein content was increased with yeast extract concentration. 7. The L-protein and nucleic acid yields from wood hydrolysate were 0.73 mg/ml and $4.92{\times}10^{-2}\;mg/ml$ respectively. 8. An optimal nucleic acid content of CHS-13 strain was observed in the medium containing 0.2% of yeast extract.

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Biodegradation of Kerosene by Pseudomonas aeruginosa K14 (Pseudomonas aeruginosa Kl4를 이용한 등유(Kerosene)의 생물학적 분해)

  • Kim, Jee-Young;Lee, Sang-Seob
    • Korean Journal of Microbiology
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    • v.44 no.2
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    • pp.156-163
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    • 2008
  • In this study, we isolated 32 strains of kerosene degrading bacteria from oil contaminated soil by enrichment culture. Isolates were screened for kerosene degradation efficiencies and K14 were selected which had the highest removal efficiency for 1,000 mg/L of kerosene. K14 were identified as Pseudomonas aeruginosa by morphological, biochemical test and 16S rDNA analysis. The optimal culture condition were determined as initial inoculated cell concentration, 1.0 g/L; substrate concentration, 1,000 mg/L; temperature $30^{\circ}C$; pH 7. When we enforced batch test in this condition, K14 degraded 72% of kerosene with 1,000 mg/L during 72 hr. And, at low concentration (200 mg/L), K14 degraded 95.8% of kerosene during 48 hr. As a result, kerosene biodegradation by Pseudomonas aeruginosa K14 could be useful for clean up of groundwater and soil contaminated with crude oil.

Enhancement of 1,3-Dihydroxyacetone Production from Gluconobacter oxydans by Combined Mutagenesis

  • Lin, Xi;Liu, Sha;Xie, Guangrong;Chen, Jing;Li, Penghua;Chen, Jianhua
    • Journal of Microbiology and Biotechnology
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    • v.26 no.11
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    • pp.1908-1917
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    • 2016
  • Wild strain L-6 was subjected to combined mutagenesis, including UV irradiation, atmospheric and room temperature plasma, and ion beam implantation, to increase the yield of 1,3-dihydroxyacetone (DHA). With application of a high-throughput screening method, mutant Gluconobacter oxydans I-2-239 with a DHA productivity of 103.5 g/l in flask-shake fermentation was finally obtained with the starting glycerol concentration of 120 g/l, which was 115.7% higher than the wild strain. The cultivation time also decreased from 54 h to 36 h. Compared with the wild strain, a dramatic increase in enzyme activity was observed for the mutant strain, although the increase in biomass was limited. DNA and amino acid sequence alignment revealed 11 nucleotide substitutions and 10 amino acid substitutions between the sldAB of strains L-6 and I-2-239. Simulation of the 3-D structure and prediction of active site residues and PQQ binding site residues suggested that these mutations were mainly related to PQQ binding, which was speculated to be favorable for the catalyzing capacity of glycerol dehydrogenase. RT-qPCR assay indicated that the transcription levels of sldA and sldB in the mutant strain were respectively 4.8-fold and 5.4-fold higher than that in the wild strain, suggesting another possible reason for the increased DHA productivity of the mutant strain.

Characteristics and breeding of a new cultivar Pleurotus eryngii var. ferulae, 'Beesan No.2' (아위느타리 신품종 '비산2호'의 육성 및 자실체 특성)

  • Shin, Pyung-Gyun;Yoo, Young-Bok;Kong, Won-Sik;Oh, Youn-Lee
    • Journal of Mushroom
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    • v.12 no.1
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    • pp.58-62
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    • 2014
  • To develop a new cultivar of King oyster mushroom white variety (Pleurotus ferulae), GW10-68 as parental strain was selected by the method of Di-mon crossing between monokaryotic strain ASI 2798-24 derived from ASI 2798 and dikaryotic strain ASI 2803. The GW10-95(ASI 2803 ${\times}$ ASI 2798-24) was shown the best cultural characteristics, selected to be a new cultivar and designed as 'Beesan No.2'. The 'Beesan No.2' was formed incompatibility line distinctly in the confrontation growth of parental strains ASI 2803, ASI 2798 and Beesan No.1. Analysis of the genetic characteristics of the new cultivar 'Beesan No.2' showed a different DNA profile as that of the control strains, ASI 2803, ASI 2798 and 'Beesan No.1', when RAPD(Random Amplified Polymorphic DNA) primer URP4 was used. The optimum temperature and pH arrange for mycelial growth were $25^{\circ}C$ and pH5~8, respectively. Fruiting body production per bottle was about 123.3 g. And also the stipe was long. This new cultivar 'Beesan No.2' of Pleurotus ferulae was characterized white-like variety of King oyster mushroom in the color of stipe, that was long and low yield compared to that of other cultuvar 'Beesan No.1'. We therefore expect that this new strain will increase of export and substitute cultivar of King oyster mushroom.