• Biotechnology and Bioprocess Engineering:BBE
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• 제10권2호
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• pp.128-135
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• 2005

Mixed-mode hydrophobic/ionic matrices exhibit a salt-tolerant property for adsorbing target protein from high-ionic strength feedstock, which allows the application of undiluted feedstock via an expanded bed process. In the present work, a new type of mixed-mode adsorbent designed for expanded bed adsorption, Fastline $PRO^{\circledR}$, was challenged for the capture of nattokinase from the high ionic fermentation broth of Bacillus subtilis. Two important factors, pH and ion concentration, were investigated with regard to the performance of nattokinase ad-sorption. Under initial fermentation broth conditions (pH 6.6 and conductivity of 10 mS/cm) the adsorption capacity of nattokinase with Fastline PRO was high, with a maximum capacity of 5,350 U/mL adsorbent. The elution behaviors were investigated using packed bed adsorption experiments, which demonstrated that the effective desorption of nattokinase could be achieved by effecting a pH of 9.5. The biomass pulse response experiments were carried out in order to evaluate the biomass/adsorbent interactions between Bacillus subtilis cells and Fastline PRO, and to demonstrate a stable expanded bed in the feedstock containing Bacillus subtilis cells. Finally, an EBA process, utilizing mixed-mode Fastline PRO adsorbent, was optimized to capture nattokinase directly from the fermentation broth. The purification factor reached 12.3, thereby demonstrating the advantages of the mixed-mode EBA in enzyme separation.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.314-314
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• 2005

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVII)
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• pp.136-137
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• 2005

• Journal of Microbiology and Biotechnology
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• 제16권1호
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• pp.32-36
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• 2006

The genome sequences from several microbes have led to the discovery of numerous open reading frames of unknown functionality. The putative bacterial epoxide hydrolase (EH) genes selected from the genome databases were examined for their activities toward various epoxides. Among the nine open reading frames (ORFs) from four microbial species, the ORF from Caulobacter crescentus showed an epoxide hydrolase activity. The kinetic resolution, using C. crescentus EH (CCEH) of the aryl epoxides such as styrene oxide, could be performed more efficiently than short aliphatic epoxides. The resolution of racemic indene oxide, which could previously be resolved only by fungal epoxide hydrolases, was effectively accomplished by CCEH.

• Journal of Microbiology and Biotechnology
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• 제13권6호
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• pp.993-997
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• 2003

Response surface methodology was applied to find the optimum conditions for the production of DXAMase (containing both dextranase and amylase activities) based on the cultivation variables (pH, temperature, and agitation rate). The experimental values from the model equation conceded with predicted values in which the predicted values for dextranase and amylase activities were 2.26 and 3.52 U/ml at pH 4, $28^{\circ}C$, 235 rpm, and the corresponding experimental values were 2.41 and 3.68 U/ml, respectively.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.313-313
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• 2005

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권6호
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• pp.419-425
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• 2001

A dense pellicular solid matrix has been fabricated by coating 4% agarose gel on to dense zironia-silica(ZS) spheres by watr-in-oil emulsification . The agarose evenly laminated the ZS bead to a depth of 30㎛, and the resultin gpellicular assembly was characterised by densities up to 2.39g/mL and a mean particle dimeter of 136 ㎛. In comparative fluidisation tests, the pellicular solid phase exhibited a two-fold greater flow velocity than commercial benchmark ad-sorbents necessary to achieve common values of bed expansion. Furthermore, the perlicular parti-cles were characterised by improved qualities of chromatographic behaviour, particularly with re-spect to a three-fold increase in the apparent effective diffusivity of lysozyme within a pellicular assembly modified with Cibacron Blue 3GA. The properties of rapid protein adsorption/desorp-tion were attributed to the physical design and pellicular deployment of the reactive surface in the solid phase. When combined with enhanced feedstock throughput, such practical advantages recommend the pellicular assembly as a base matrix for the selective recovery of protein products from complex, particulate feedstocks(whole fermentation broths, cell disruptates and biological extracts).

• Journal of Microbiology and Biotechnology
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• 제34권5호
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• pp.1154-1163
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• 2024

Glucosylation is a well-known approach to improve the solubility, pharmacological, and biological properties of flavonoids, making flavonoid glucosides a target for large-scale biosynthesis. However, the low yield of products coupled with the requirement of expensive UDP-sugars limits the application of enzymatic systems for large-scale. C. glutamicum is a Gram-positive and generally regarded as safe (GRAS) bacteria frequently employed for the large-scale production of amino acids and biofuels. Due to the versatility of its cell factory system and its non-endotoxin producing properties, it has become an attractive system for the industrial-scale biosynthesis of alternate products. Here, we explored the cell factory of C. glutamicum for efficient glucosylation of flavonoids using apigenin as a model flavonoid, with the heterologous expression of a promiscuous glycosyltransferase, YdhE from Bacillus licheniformis and the endogenous overexpression of C. glutamicum genes galU1 encoding UDP-glucose pyrophosphorylase and pgm encoding phosphoglucomutase involved in the synthesis of UDP-glucose to create a C. glutamicum cell factory system capable of efficiently glucosylation apigenin with a high yield of glucosides production. Consequently, the production of various apigenin glucosides was controlled under different temperatures yielding almost 4.2 mM of APG1(apigenin-4'-O-β-glucoside) at 25℃, and 0.6 mM of APG2 (apigenin-7-O-β-glucoside), 1.7 mM of APG3 (apigenin-4',7-O-β-diglucoside) and 2.1 mM of APG4 (apigenin- 4',5-O-β-diglucoside) after 40 h of incubation with the supplementation of 5 mM of apigenin and 37℃. The cost-effective developed system could be used to modify a wide range of plant secondary metabolites with increased pharmacokinetic activities on a large scale without the use of expensive UDP-sugars.

• KSBB Journal
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• 제23권4호
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• pp.317-322
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• 2008

본 연구를 통하여 자체 구동형 모터를 갖는 BOD 센서를 개발하였으며, 6,000초 이상 측정한 결과 안정적인 측정이 가능함을 확인하였다. 응답시간은 30초 이내, 재현성은 1 ppm 이내, 선형성은 99%의 우수한 성능을 갖는 BOD 센서를 개발하였다. 최대 산소소모속도 (Maximum Oxygen Uptake Rate, $OUR_{max}$)와 $BOD_5$ 상관관계는 $BOD_5$ (ppm)=-2,490+33,889 ($OUR_{max}$)로서, 95.6%의 우수한 선형성을 보였다. 자체구동형 BOD 센서를 이용하여 시료의 전처리부터 BOD의 측정까지 자동으로 제어 및 측정되는 시스템을 구성하였다. 본 연구를 통하여 최대 산소소모속도 ($OUR_{max}$)와 $BOD_5$ 상관관계를 구한 후 수분내에 $BOD_5$ 값을 예측할 수 있었다.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2003년도 생물공학의 동향(XIII)
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• pp.699-700
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• 2003