• Title/Summary/Keyword: mixed-culture

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Xylanase Production by Mixed Culture Using Crude Hemicellulose from Rice Straw Black Liquor and Peat Moss as an Inert Support

  • Shata, Hoda Mohamed Abdel Halim;El-Deen, Azza Mohmed Noor;Nawwar, Galal Abdel Moen;Farid, Mohmed Abdel Fattah
    • Journal of Applied Biological Chemistry
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    • v.57 no.4
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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.

The Effectiveness of Jeju Island Mixed Reality Tourism Application: Focusing on the Moderating Role of Users' K-Culture Involvement

  • Yoo, Seungchul;Jung, Kwanghee;Nguyen, Vinh T.;Piscarac, Diana
    • International Journal of Advanced Culture Technology
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    • v.8 no.2
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    • pp.116-128
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    • 2020
  • In this study, we introduce a multi-modal mixed reality (MR) application for advertising the main touristic landmarks on Jeju Island, and evaluate its effectiveness based on the Technology Acceptance Model (TAM) with a focus on the user's involvement in Korean culture (K-Culture). Specifically, we deployed several stimuli to enable users to retrieve information, visualize a variety of heritage content such as text, images, videos, virtual artifacts, and immerse in a VR environment to experience the heritage locations. The results of the online survey with 436 participants showed that for consumers with low K-Culture involvement, Perceived Usefulness and Perceived Ease-of-Use did not affect their Intention to Visit the island. Still, it had a significant impact on their Intention to Use the application. On the other hand, for the group with high K-Culture involvement, Perceived Usefulness had no effect on the Intention to Use and Intention to Visit. However, Perceived Ease-of-Use had a significant impact on their Intention to Use the application and Intention to Visit Jeju Island. Therefore, when user involvement in K-Culture is high, convenience of use has played a significant role in sensory media usage and the intention to visit, regardless of the usefulness of the mixed reality content. In contrast, users with low K-Culture involvement primarily focused on the functional aspects of the application. These findings open the path for follow-up studies on K-Culture involvement and immersive media tourism marketing, which will benefit digital tourism marketing and Korea's tourism industry.

Effect of Hydrocarbon Uptake Modes on Oil Degradation Rate by Mixed Cultures of Petroleum Degraders (Hydrocarbon Uptake Modes에 따른 유류분해 미생물 혼합체의 원유분해능)

  • 고성환;이홍금;김상진
    • KSBB Journal
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    • v.13 no.5
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    • pp.606-614
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    • 1998
  • In this study, biodegradation rate of Arabian light crude oil by mixed cultures of selected petroleum-degraders was determined. Their modes of hydrocarbon uptake were then observed to determine whether there are differences in biodegradation rate by the mixed cultures. By the mixed cultures of petroleum-degraders having same modes of hydrocarbon uptake, such as strain US1 and K1 (using pseudo-solubilized hydrocarbons by a biosurfactants), K2-2 and P1(using hydrocarbons by direct contact), CL 180 and IC-10 (mixed type of uptake modes), the biodegradation rates of aliphatics in the crude oil were increased more than those by their pure cultures, about 40%, 25% and 20%, respectively. Biodegradation rate of strain KH3-2 (using only water- dissolved hydrocarbons) was increased by mixed cultures with strain K1, CL180 or IC-10 possessing high emulsifying activity. However, the biodegradation rate of the crude oil was decreased about 20%-40% by the mixed cultures of petroleum-degraders having different mode of hydrocarbon uptake, such as addition of strain US1 or K1 in the cultures of K2-2 or P1. Biosurfactants produced by US1 or K1 seems to enhance the emulsification of crude oil in aqueous phase but inhibit the attachment of K2-2 or P1 to crude oil. As same phenomena, the addition to Triton X-100 into the culture of strain US1, K1, CL180, IC-10 or KH3-2 increased the biodegradation rate, but the addition in the culture of strain K2-2 or P1 decreased the biodegradation rate. The mixed culture made of CL180, IC-10 and KH3-2 degraded 61.5% of aliphatics and 69% of aromatics in 3% (v/v) of Arabian light crude oil added.

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Survival Strategies of the Rotifer Brachionus rotundiformis for Coexisting with the Copepod Apocyclops borneoensis in Laboratory Culture

  • Jung, Min-Min
    • Fisheries and Aquatic Sciences
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    • v.15 no.1
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    • pp.57-62
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    • 2012
  • Interspecific relationship between a euryhaline rotifer Brachionus rotundiformis and a cyclopoid copepod Apocyclops borneoensis was investigated in the laboratory culture. In a mixed culture of B. rotundiformis and A. borneoensis, population growth of B. rotundiformis was suppressed from day 10, while growth in a monoculture population continuously increased throughout the experimental period. However, the population growth of A. borneoensis in the mixed culture did not markedly differ from that in a monoculture population. Suppression of B. rotundiformis growth coincided with a decrease in the numbers of both non-egg-bearing and egg-bearing females, and increasing resting egg formation. Growth of A. borneoensis was not affected by the presence of the rotifer. However, relative growth index of ovisac bearing females in the mixed culture was 1.62 times higher than that in the monoculture. Presence of the copepod did not greatly reduce the food available to the rotifer population. The rotifer B. rotundiformis responded in a unique way, to stresses such as physical damage (filtering by A. borneoensis) with the production of many resting eggs to increase its chances of survival.

Alcaligenes eutrophus 균주의 성장과 Poly-Beta-hydroxybutyrate 합성에 미치는 포도당과 암모늄농도의 영향

  • 이용우;유영제
    • Microbiology and Biotechnology Letters
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    • v.18 no.6
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    • pp.607-612
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    • 1990
  • The biodegradation of Aroclor 1242 was investigated by the mixed cultivation of the natural bacterial isolates and a genetically engineered microorganism (GEM). The natural strain of MS-1003 degraded the Aroclor 1242 through the ortho-cleavage pathway, while the other strains through the meta-cleavage pathway. When the MS-1003 strain was additionally inoculated into the 1 day culture of the DJ-26 strain and then cultivated for 2 days, the Aroclor was degraded up to 86% and resulted in increase of the meta-cleavage product. But in the MS-1003 culture inoculated with the DJ-26, degradation of the Aroclor was limited to the level of each pure culture. By the mixed cultivation of the DJ-26 strain together with the DJ-12 or its GEM strain of DF-10, which degrades the Aroclor through the meta-cleavage pathway, degradation of the Aroclor as well as production of the meta-cleavage compound were lower than those of each pure culture. The degradation of Aroclor 1242 by the GEM strain was not improved over the parental strain. Therefore, a form of cometaboiism of Aroclor 1242 was found in the mixed culture of the DJ-26 and MS-1003 strains which degrade the Aroclor through the different metabolic pathway, but in the mixed culture of the DJ-26 and DJ-12 strains degrading Aroclor 1242 through the same pathway, a kind of competetion for the substrate was observed.

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Strain Selection and Optimization of Mixed Culture Conditions for Lactobacillus pentosus K1-23 with Antibacterial Activity and Aureobasidium pullulans NRRL 58012 Producing Immune-Enhancing β-Glucan

  • Sekar, Ashokkumar;Kim, Myoungjin;Jeong, Hyeong Chul;Kim, Keun
    • Journal of Microbiology and Biotechnology
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    • v.28 no.5
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    • pp.697-706
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    • 2018
  • Lactobacillus pentosus K1-23 was selected from among 25 lactic acid bacterial strains owing to its high inhibitory activity against several pathogenic bacteria, including Escherichia coli, Salmonella typhimurium, S. gallinarum, Staphylococcus aureus, Pseudomonas aeruginosa, Clostridium perfringens, and Listeria monocytogenes. Additionally, among 13 strains of Aureobasidium spp., A. pullulans NRRL 58012 was shown to produce the highest amount of ${\beta}$-glucan ($15.45{\pm}0.07%$) and was selected. Next, the optimal conditions for a solid-phase mixed culture with these two different microorganisms (one bacterium and one yeast) were determined. The optimal inoculum sizes for L. pentosus and A. pullulans were 1% and 5%, respectively. The appropriate inoculation time for L. pentosus K1-23 was 3 days after the inoculation of A. pullulans to initiate fermentation. The addition of 0.5% corn steep powder and 0.1% $FeSO_4$ to the basal medium resulted in the increased production of lactic acid bacterial cells and ${\beta}$-glucan. The following optimal conditions for solid-phase mixed culture were also statistically determined by using the response surface method: $37.84^{\circ}C$, pH 5.25, moisture content of 60.82%, and culture time of 6.08 days for L. pentosus; and $24.11^{\circ}C$, pH 5.65, moisture content of 60.08%, and culture time of 5.71 days for A. pullulans. Using the predicted optimal conditions, the experimental production values of L. pentosus cells and ${\beta}$-glucan were $3.15{\pm}0.10{\times}10^8CFU/g$ and $13.41{\pm}0.04%$, respectively. This mixed culture may function as a highly efficient antibiotic substitute based on the combined action of its anti-pathogenic bacterial and immune-enhancing activities.

Kinetics of nitrification and acrylamide biodegradation by Enterobacter aerogenes and mixed culture bacteria in sequencing batch reactor wastewater treatment systems

  • Madmanang, Romsan;Jangkorn, Siriprapha;Charoenpanich, Jittima;Sriwiriyarat, Tongchai
    • Environmental Engineering Research
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    • v.24 no.2
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    • pp.309-317
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    • 2019
  • This study evaluated the kinetics of acrylamide (AM) biodegradation by mixed culture bacteria and Enterobacter aerogenes (E. aerogenes) in sequencing batch reactor (SBR) systems with AQUASIM and linear regression. The zero-order, first-order, and Monod kinetic models were used to evaluate the kinetic parameters of both autotrophic and heterotrophic nitrifications and both AM and chemical oxygen demand (COD) removals at different AM concentrations of 100, 200, 300, and 400 mg AM/L. The results revealed that both autotrophic and heterotrophic nitrifications and both AM and COD removals followed the Monod kinetics. High AM loadings resulted in the transformation of Monod kinetics to the first-order reaction for AM and COD removals as the results of the compositions of mixed substrates and the inhibition of the free ammonia nitrogen (FAN). The kinetic parameters indicated that E. aerogenes degraded AM and COD at higher rates than mixed culture bacteria. The FAN from the AM biodegradation increased both heterotrophic and autotrophic nitrification rates at the AM concentrations of 100-300 mg AM/L. At higher AM concentrations, the FAN accumulated in the SBR system inhibited the autotrophic nitrification of mixed culture bacteria. The accumulation of intracellular polyphosphate caused the heterotrophic nitrification of E. aerogenes to follow the first-order approximation.

Studies on a Mixed Yeast Culture -Part 1. Interactions in a Mixed Yeast Culture- (효모의 혼합 배양에 관한 연구 -제1보 혼합배양의 상호작용-)

  • Pyun, Yu-Ryang;Kwon, Tai-Wan;Yu, Ju-Hyun
    • Korean Journal of Food Science and Technology
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    • v.9 no.4
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    • pp.306-312
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    • 1977
  • A mixed culture of Candida tropicalis and Trichosporon cutaneum was carried out using a n-paraffin medium. The growth of C. tropicalis was markedly enhanced by the mixed culture with T. cutaneum which did not grow on n-paraffin. C. tropicalis extracellularly excreted free fatty acids as metabolic products of n-paraffin in the culture medium. T. cutaneum appeared to assimilate these free fatty acids which were growth inhibitors for C. tropicalis, threreby enhancing the growth of C. tropicalis.

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유사 생합성 경로를 가진 Streptomyces sp.의 혼합배양을 이용한 Doxorubicin 생합성

  • Choi, Yun-Hwa;Hong, Young-Soo;Lim, Jai-Yun;Lee, Jung-Joon
    • Microbiology and Biotechnology Letters
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    • v.25 no.6
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    • pp.580-585
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    • 1997
  • We selected two mutants namely strain D5 and Nu23 by mutagenesis of anthracycline producing Streptomyces: the former is an $\varepsilon$-rhodomycinone overproducing mutant selected from Streptomyces sp. C5, a baumycin producer and the latter, a blocked mutant of early pathway for doxorubicin biosynthesis obtained from Streptomyces peucetius ATCC 27952, a doxorubicin producer. The mutant strain Nu23 does not produce anthracycline metabolites but retains the most of enzyme activities converting aklavinone to doxorubicin and the mutant strain D5 produced $\varepsilon$-rhodomycinone at a level of 150 $\mu$g/ml. These strains were grown separately in NDYE medium and each was mixed at day 3 by equal volume of culture broth but the quantity of doxorubicin produced was far below an estimation based on the level of $\varepsilon$-rhodomycinone normaly produced by the strain D5. On the other hand doxorubicin was reached at maximum level after 4 days in the mixed culture condition which was composed of culture broth of strain D5 grown for 6 day and that of strain Nu23 grown for 3 day. It was turned out that the growth of mutant strain D5 was inhibited by the accumulation of daunorubicin and doxorubicin in mixed culture broth, which cause the limitation of $\varepsilon$-rhodomycinone.

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Lactic Fermentation of Soymilk by Mixed Culture of Lactobacillus bulgaricus and Saccharomyces uvarum (Lactobacillus delbrueckii subsp. bulgaricus와 Saccharomyces uvarum의 혼합배양에 의한 두유의 젖산발효)

  • 유주현;진효상;백영진
    • Microbiology and Biotechnology Letters
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    • v.19 no.4
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    • pp.413-418
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    • 1991
  • When L, bulgurzcus KFCC 35462 and S. uvarum KFCC 32021 were mixed cultured in soymilk, gorwth of L. bulgaricus was stimulated with growth of S. uvarunz little affected. Cultured in soymilk singly, L. bulgaricus produced only 0.07%) of acids. S. uvarum, cultured singly, produced 0.40% of ethanol and 0.18% of acids. Mixed culture of both produced 0.27% of acids and 0.42% of ethanol. Thus. S. uvarurrz was not much affected in growth and ethanol fermentation by L. bulgariccus, while L, bulgarzcus was stimulated by Sacch. uvarunz in growth but not in acid fermentation.

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