• Mycobiology
• /
• v.51 no.4
• /
• pp.230-238
• /
• 2023

Glabridin is a well-known active isoflavone found in the root of licorice (Glycyrrhiza glabra L.) that possess a wide range of biological activity. Plant cells, hairy roots, and fungal endophytes cultures are the most important alternative methods for plant resources conservation and sustainable production of natural compounds, which has received much attention in recent decades. In the present study, an efficient culture condition was optimized for the biomass accumulation and glabridin production from fungal endophyte Aspergillus eucalypticola SBU-11AE isolated from licorice root. Type of culture medium, range of pH, and licorice root extract (as an elicitor) were tested. The results showed that the highest and lowest biomass production was observed on PCB medium (6.43 ± 0.32 g/l) and peptone malt (5.85 + 0.11 g/l), respectively. The medium culture PCB was produced the highest level of glabridin (7.26 ± 0.44 mg/l), while the lowest level (4.47 ± 0.02 mg/l) was obtained from the medium peptone malt. The highest biomass (8.51 ± 0.43 g/l) and glabridin (8.30 ± 0.51 mg/l) production were observed from the PCB medium adjusted with pH = 6, while the lowest value of both traits was obtained from the same medium with pH = 7. The highest production of total glabridin (10.85 ± 0.84 mg/l) was also obtained from the culture medium treated with 100 mg/l of the plant root extract. This information can be interestingly used for the commercialization of glabridin production for further industrial applications.

• Journal of Microbiology and Biotechnology
• /
• v.31 no.4
• /
• pp.570-583
• /
• 2021

Pyrococcus furiosus α-amylase can hydrolyze α-1,4 linkages in starch and related carbohydrates under hyperthermophilic condition (~ 100℃), showing great potential in a wide range of industrial applications, while its relatively low productivity from heterologous hosts has limited the industrial applications. Bacillus subtilis, a gram-positive bacterium, has been widely used in industrial production for its non-pathogenic and powerful secretory characteristics. This study was conducted to increase production of P. furiosus α-amylase in B. subtilis through three strategies. Initial experiments showed that co-expression of P. furiosus molecular chaperone peptidyl-prolyl cis-trans isomerase through genomic integration mode, using a CRISPR/Cas9 system, increased soluble amylase production. Therefore, considering that native P. furiosus α-amylase is produced within a hyperthermophilic environment and is highly thermostable, heat treatment of intact culture at 90℃ for 15 min was performed, thereby greatly increasing soluble amylase production. After optimization of the culture conditions (nitrogen source, carbon source, metal ion, temperature and pH), experiments in a 3-L fermenter yielded a soluble activity of 3,806.7 U/ml, which was 3.3- and 28.2-fold those of a control without heat treatment (1,155.1 U/ml) and an empty expression vector control (135.1 U/ml), respectively. This represents the highest P. furiosus α-amylase production reported to date and should promote innovation in the starch liquefaction process and related industrial productions. Meanwhile, heat treatment, which may promote folding of aggregated P. furiosus α-amylase into a soluble, active form through the transfer of kinetic energy, may be of general benefit when producing proteins from thermophilic archaea.

• Journal of the Korean Society of Food Culture
• /
• v.23 no.5
• /
• pp.621-628
• /
• 2008

The principal objective of this study was to develop the optimal recipe for muffins containing dried broccoli powder. In this study, broccoli powder was substituted for wheat flour in order to reduce its content. The study was conducted by determining the optimal sensory composite recipe, by preparing muffins with different levels of broccoli powder (A), sugar (B), and butter (C), by C.C.D (Central composite design) and performing sensory evaluation and analysis via RSM (Response surface methodology). The sensory measurements yielded significant values for appearance, flavor (p<0.01), texture (p<0.05), overall quality (p<0.05) and color (p<0.05), whereas instrumental measurements yielded significant values in lightness (p<0.01), redness (p<0.05), yellowness, baking loss rate (p<0.05), hardness (p<0.05), cohesiveness (p<0.01) and gumminess (p<0.05). The optimum formulations processed by numerical and graphical optimization were determined as 13.58g of broccoli powder, 92.02g of sugar, and 71.97g of butter.

• The Korean Journal of Mycology
• /
• v.40 no.4
• /
• pp.204-209
• /
• 2012

In this study, a novel yeast, Y111-5 for Makgeolli manufacture was selected from Nuruk yeasts, and its optimal culture condition were investigated. The Y111-5 strain was identified as Saccharomyces cerevisiae by phylogenetic analysis of 18S RNA sequence. The maximal growth was obtained when the yeast was cultivated at $30^{\circ}C$ for 15 h in the medium containing sucrose 9% and yeast extract 5%.

• Journal of the Korean Society of Food Culture
• /
• v.19 no.2
• /
• pp.193-199
• /
• 2004

The purpose of this study was to determine the organoleptic charateristics of cauliflower pickles made in various compounding ratio according to central conposite design for optimum organoleptic characteristics of the cauliflower pickles. The optimum mixing condition of cauliflower pickles were optimized, using central composite design with 3 variables and 3 levels, by response surface methodology. The various kinds of cauliflower pickle were made in various compounding ratio of vinegar, salt and sucrose - critical ingredients of pickle recipe - and were presented to reliable panels, who graded the subjects in 7 degrees for 4 items : color, flavor, hardness and overall quality. The optimum mixing conditions of cauliflower pickle were 603.50g of vinegar, 80.13g of salt and 251.07g of sucrose in the maximum point of overall quality.

• Journal of the Korean Society of Food Culture
• /
• v.34 no.3
• /
• pp.361-368
• /
• 2019

The purpose of this study was to establish the best optimized extraction condition for the optimal development of fresh maca beverage using low temperature extraction and enzyme treatment. Low temperatures were applied to prevent heat-related nutritional loss during the extraction process. Best extraction conditions were investigated based on the ratio of maca to water, the ratio of enzymes, extraction temperature and time, and agitation. The optimal enzyme conditions were also examined after the treatment of cellulase:pectinase mixture to maintain the original color and flavor, as well as to increase the extraction yield. When cellulase:pectinase was 1:1, the extraction rate ranged from 77.84 to 79.29%. In addition, the best extraction rate was found when maca was mixed with twice volume of water and incubated at $45^{\circ}C$ ($84.05{\pm}0.32%$) with 90 rpm ($87.13{\pm}0.46%$) agitation for 3 hours ($84.73{\pm}0.29%$). Furthermore, sensory evaluation showed a high score in flavor, sweetness, and overall acceptability after adding 3% jujube concentrate into a fresh maca beverage.

• KSBB Journal
• /
• v.30 no.6
• /
• pp.283-290
• /
• 2015

In this study was selected the cellulolytic microorganism and investigated optimum condition of cellulase production for the cellulosic bioethanol production. A bacterial strain Paenibacillus jamilae BRC15-1, was isolated from soil of domestic reclaimed land. For optimizing cellulase production from the selected strain, various culture parameters were investigated such as culture medium, pH (pH 4~10), temperature ($25{\sim}50^{\circ}C$) and culture time (2~72 h). As a result, P. jamilae BRC15-1 efficiently produced cellulase from cellulosic biomass under following conditions: 24 h of culture time (pH 7, $40^{\circ}C$) in manufactured media of CMC (carboxymethyl cellulose) with peptone. Optimum saccharifying condition of crude enzyme produced from P. jamilae BRC15-1 was identified on pH 6 and $40^{\circ}C$ of reaction temperature, respectively. This crude enzyme from P. jamilae BRC15-1 was used for saccharification of pretreated sweet sorghum (Sorghum bicolor var. dulciusculum Ohwi) bagasse under the optimal condition. Finally, pretreated sweet sorghum bagasse including 0.1 g of glucan was saccharified by crude enzyme of P. jamilae BRC15-1 into 2.75 mg glucose, 0.79 mg xylose and 1.12 mg arabinose.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.7 no.5
• /
• pp.237-251
• /
• 2002

The recent progress on metabolic systems engineering was reviewed based on our recent research results in terms of (1) metabolic signal flow diagram approach, (2) metabolic flux analysis (MFA) in particular with intracellular isotopomer distribution using NMR and/or GC-MS, (3) synthesis and optimization of metabolic flux distribution (MFD), (4) modification of MFD by gene manipulation and by controlling culture environment, (5) metabolic control analysis (MCA), (6) design of metabolic regulation structure, and (7) identification of unknown pathways with isotope tracing by NMR. The main characteristics of metabolic engineering is to treat metabolism as a network or entirety instead of individual reactions. The applications were made for poly-3-hydroxybutyrate (PHB) production using Ralstonia eutropha and recombinant Escherichia coli, lactate production by recombinant Saccharomyces cerevisiae, pyruvate production by vitamin auxotrophic yeast Toluropsis glabrata, lysine production using Corynebacterium glutamicum, and energetic analysis of photosynthesic microorganisms such as Cyanobateria. The characteristics of each approach were reviewed with their applications. The approach based on isotope labeling experiments gives reliable and quantitative results for metabolic flux analysis. It should be recognized that the next stage should be toward the investigation of metabolic flux analysis with gene and protein expressions to uncover the metabolic regulation in relation to genetic modification and/ or the change in the culture condition.

• Microbiology and Biotechnology Letters
• /
• v.27 no.2
• /
• pp.172-178
• /
• 1999

In this study, we tested possibility of replacing nitrite salts, which were always added during the meat product processing, with the metabolites produced by antimicrobial and red pigment producing Monascus strains. We have already shown that Monascus No. 116 strain has the highest antimicrobial activity among the strains isolated from Ang-Khak. Monascus isolate No. 229 was chosen due to its outstanding red pigment producing ability. The red pigment production by No. 229 was highest in the medium containing 8% sucrose, 2% yeast extract, 0.1% K2HPO4, 0.5% MgSO4. Optimum pH and temperature for the red pigment production were pH 6.2 and 3$0^{\circ}C$, was found in spot or Rf value 0.54 on TLC plate using ethyl acetate-acetone-water (4:4:1, v/v/v) as development solvent system. Isolate No. 116 and No. 229 were cultured in a optimal condition for the antimicrobial activity and red pigmentation. The culture concentrates were applied in situ to the production of instantly processed ham. Mixed application of 89 ppm Na-nitrite and 300 ppm of culture broth concentrate of Monascus isolate No. 116 and 500 ppm of red color produced by Monascus isolate No. 229 showed similar results with the single application of 94 ppm Na-nitrite. These results confirmed that the antimicrobial activity and red pigment of Monascus strains might be valuable to replace Na-nitrite salt in meat processing.

• Journal of Microbiology and Biotechnology
• /
• v.29 no.6
• /
• pp.933-943
• /
• 2019

Gamma-aminobutyric acid (GABA)-producing strains were isolated from four edible insects and subjected to 16S rRNA sequence analysis. Among the four GABA-producing bacteria, Enterococcus avium JS-N6B4 exhibited the highest GABA-production, while cultivation temperature, initial pH, aerobic condition, and mono-sodium glutamate (MSG) feeding were found to be the key factors affecting GABA production rate. The culture condition was optimized in terms of glucose, yeast extract, and MSG concentrations using response surface methodology (RSM). GABA production up to 16.64 g/l was obtained under the conditions of 7 g/l glucose, 45 g/l yeast extract, and 62 g/l MSG through the optimization of medium composition by RSM. Experimental GABA production was 13.68 g/l, which was close to the predicted value (16.64 g/l) calculated from the analysis of variance, and 2.79-fold higher than the production achieved with basic medium. Therefore, GABA-producing strains may help improve the GABA production in edible insects, and provide a new approach to the use of edible insects as effective food biomaterials.