• Journal of Microbiology and Biotechnology
• /
• 제27권3호
• /
• pp.450-459
• /
• 2017

This study evaluated the effects of culture conditions, including carbon and nitrogen sources, L-monosodium glutamate (MSG), and initial pH, on gamma-aminobutyric acid (GABA) production by Lactobacillus brevis HYE1 isolated from kimchi, a Korean traditional fermented food. L. brevis HYE1 was screened by the production analysis of GABA and genetic analysis of the glutamate decarboxylase gene, resulting in 14.64 mM GABA after 48 h of cultivation in MRS medium containing 1% (w/v) MSG. In order to increase GABA production by L. brevis HYE1, the effects of carbon and nitrogen sources on GABA production were preliminarily investigated via one-factor-at-a-time optimization strategy. As the results, 2% maltose and 3% tryptone were determined to produce 17.93 mM GABA in modified MRS medium with 1% (w/v) MSG. In addition, the optimal MSG concentration and initial pH were determined to be 1% and 5.0, respectively, resulting in production of 18.97 mM GABA. Thereafter, response surface methodology (RSM) was applied to determine the optimal conditions of the above four factors. The results indicate that pH was the most significant factor for GABA production. The optimal culture conditions for maximum GABA production were also determined to be 2.14% (w/v) maltose, 4.01% (w/v) tryptone, 2.38% (w/v) MSG, and an initial pH of 4.74. In these conditions, GABA production by L. brevis HYE1 was predicted to be 21.44 mM using the RSM model. The experiment was performed under these optimized conditions, resulting in GABA production of 18.76 mM. These results show that the predicted and experimental values of GABA production are in good agreement.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제6권1호
• /
• pp.6-10
• /
• 2001

The production of chitosan from the mycelia of Absidia coerulea was studied to improve cell growth and chitosan productivity. Culture conditions were optimized in batch cultivation (pH 4.5, agitator speed of 250 rpm, and aeration rate of 2 vvm) and the maximum chitosan concentration achieved was 2.3g/L under optimized conditions. Continuous culture was carried out successfully by the formation of new growth spots under optimized conditions, with a chitosan productivity of 0.052g/L(sup)-1 h(sup)-1, which is the highest value to date, and was obtained at a dulution rate of 0.05h(sup)-1. Cell chitosan concentrations reached about 14% in the steady state, which is similar to that achieved in batch culture. This study shows that for the continuous culture of Absidia coerulea it is vital to control the medium composition.

• 한국미생물·생명공학회지
• /
• 제30권1호
• /
• pp.63-67
• /
• 2002

본 연구에서 사용된 Bifidobacterium은 모유를 섭취한 유아의 분변으로부터 분리었으며 16s rRNA 염기서열분석 결과 Bifidobacterium longum속으로 동정되어 Bifidobacterium SH2라 명명하였다. Bifidobacterium SH2의 고농도 배양을 위하여 기본 배지로 MRS 배지를 변형하여 최적화한 결과 최적 배지의 조성은 50g/L lactose, 10 g/L beef extract, 10 g/L peptone, 5 g/L yeast extract, 7 g/L sodium acetate, 2 g/L ammonium citrate, 2 g/L disodium phosphat, 1 g/L tween 80, 0.2 g/L $MnSO_4$, 0.5 g/L L-cysteine이었다. 배양조건을 최적화한 결과 pH는 5.0에서, 온도는$ 37^{\circ}C$에서 균체량이 최대로 나타났다. 배지와 배양 조건을 최적화하여 건조 균체량과 생균수가 MRS 배지 보다 각각 2.7배, 1.8배 증가한 결과를 얻었다.

• Journal of Pharmaceutical Investigation
• /
• 제40권6호
• /
• pp.363-366
• /
• 2010

Identification of compounds that function as P-glycoprotein (P-gp) substrates or inhibitors can facilitate the selection and optimization of new drug candidates. The purpose of this study is to optimize the experimental conditions for in vitro P-gp assay using LLC-GA5 cells, which is a well-known transformant cell line derived by transfecting LLC-PK1 with human MDR1. The amount of rhodamine123 transported by the LLC-GA5 and LLC-PK1 cells was evaluated under the following experimental conditions: 3 different types of transport media, colchicine pretreatment or nontreatment of the cells in the culture media, and with and without poly-L-lysine coating of the culture plates. The assay sensitivity was found to considerably differ depending on the diluents used in the transport media. P-gp-mediated transport in LLC-GA5 cells was most clearly characterized in the Hanks' balanced salt solution based transport media. The sensitivity of P-gp-mediated transport was not changed by colchicine pretreatment or poly-L-lysine coating of the culture plates.

• 한국미생물·생명공학회지
• /
• 제48권4호
• /
• pp.515-524
• /
• 2020

With the increasing demand for enzymes in industrial applications there is a growing need to easily produce industrially important microbial enzymes. This study was carried out to screen the indigenous refinery bacterial isolates for their production of two industrially important enzymes i.e. lipase and protease. A total of 15 bacterial strains were isolated using Soil Extract Agar media from the oil-contaminated environment and one was shown to produce high quality lipase and protease enzymes. The culture conditions (culture duration, temperature, source of nitrogen, carbon, and pH) were optimized to produce the optimum amount of both the lipase (37.6 ± 0.2 Uml-1) and the protease (41 ± 0.4 Uml-1) from this isolate. Productivity of both enzymes was shown to be maximized at pH 7.5 in a medium containing yeast extract and peptone as nitrogen sources and sucrose and galactose as carbon sources when incubated at 35 ± 1℃ for 48 h. Bacterial strain SAB06 was identified as Bacillus licheniformis (MT250345) based on biochemical, morphological, and molecular characteristics. Further studies are required to evaluate and optimize the purification and characterization of these enzymes before they can be recommended for industrial or environmental applications.

• Journal of Microbiology and Biotechnology
• /
• 제24권2호
• /
• pp.188-196
• /
• 2014

Extracellular production of recombinant human bone morphogenetic protein-7 (rhBMP-7) was carried out through the fermentation of Bacillus subtilis. Three significant fermentation conditions and medium components were selected and optimized to enhance the rhBMP-7 production by using the response surface methodology (RSM). The optimum values of the three variables for the maximum extracellular production of rhBMP-7 were found to be 2.93 g/l starch, 5.18 g/l lactose, and a fermentation time of 34.57 h. The statistical optimization model was validated with a few fermentations of B. subtilis in shake flasks under optimized and unoptimized conditions. A 3-L jar fermenter using the shake-flask optimized conditions resulted in a higher production (413 pg/ml of culture medium) of rhBMP-7 than in a shake flask (289.1 pg/ml), which could be attributed to the pH being controlled at 6.0 and constant agitation of 400 rpm with aeration of 1 vvm.

• Journal of Microbiology and Biotechnology
• /
• 제34권4호
• /
• pp.757-764
• /
• 2024

Despite considerable advancements achieved using next-generation sequencing technologies in exploring microbial diversity, several species of the gut microbiome remain unknown. In this transformative era, culturomics has risen to prominence as a pivotal approach in unveiling realms of microbial diversity that were previously deemed inaccessible. Utilizing innovative strategies to optimize growth and culture medium composition, scientists have successfully cultured hard-tocultivate microbes. This progress has fostered the discovery and understanding of elusive microbial entities, highlighting their essential role in human health and disease paradigms. In this review, we emphasize the importance of culturomics research on the gut microbiome and provide new theories and insights for expanding microbial diversity via the optimization of cultivation conditions.

• 한국약용작물학회:학술대회논문집
• /
• 한국약용작물학회 2008년도 추계학술발표회
• /
• pp.328-329
• /
• 2008

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 1996년도 공동 춘계학술대회
• /
• pp.56.2-56
• /
• 1996

No Abstract, See Full Text

• Journal of Microbiology and Biotechnology
• /
• 제15권1호
• /
• pp.66-71
• /
• 2005

Doxorubicin is a clinically important anticancer polyketide compound that is typically produced by Streptomyces peucetius var. caesius. To improve doxorubicin productivity by S. peucetius, a doxorubicin pathway-specific regulatory gene, dnrI, was cloned into a high-copy-number plasmid containing a catechol promoter system. The S. peucetius containing the recombinant plasmid exhibited approximately 9.5-fold higher doxorubicin productivity compared with the wild-type S. peucetius. The doxorubicin productivity by this recombinant S. peucetius strain was further improved through the optimization of culture media composition. Based on the Fractional Factorial Design (FFD), cornstarch, $K_2HPO_4$, and $MgSO_4$ were identified to be the key factors influencing doxorubicin productivity. The Response Surface Method (RSM) results based on 20 independent culture conditions with varying amounts of key factors predicted the highest theoretical doxorubicin productivity of 11.1 mg/l with corn starch of 46.33 g/l, $K_2HPO_4$ of 4.63 g/l, and $MgSO_4$ of 9.26 g/l. The doxorubicin productivity of the recombinant S. peucetius strain with the RSM-based optimized culture condition was experimentally verified to be 11.46 mg/l, which was approximately 30.8-fold higher productivity compared with the wild-type S. peucetius without culture media optimization.