• Korean Journal of Soil Science and Fertilizer
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• v.49 no.5
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• pp.461-468
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• 2016

One of the important phytohormones produced by plant growth promoting bacteria is the auxin; indole-3-acetic acid (IAA), with L-tryptophan as the precursor. In this study, we focused on the investigation of optimal conditions for the production of IAA by Bacillus megaterium BM5. We investigated culturing conditions, such as incubation temperature, pH of the culture medium and incubation period, with varying media components such as inoculation volume, tryptophan concentration and carbon and nitrogen source. Besides, optimization study intended for high IAA production was carried out with fermentation parameters such as rpm and aeration. The initial yield of $42{\mu}g\;IAA\;ml^{-1}$ after 24 hr increased to $85{\mu}g\;ml^{-1}$ when 5% (v/v) of L-tryptophan was used in the culture broth. The maximum yield of $320{\mu}g\;IAA\;ml^{-1}$ was observed in trypticase soy broth (TSB) supplemented with starch and soybean meal as C and N sources with a C/N ratio of 3:1 (v/v) at $30^{\circ}C$, pH 8.0 for 48 hrs with 1.0 vvm and 250 rpm in 5 L working volume using 10 L scale fermenter. The bacterial auxin extracted from the culture broth was confirmed by thin layer chromatography and high-performance liquid chromatography and effect on plant growth was confirmed by root elongation test.

• Journal of Microbiology and Biotechnology
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• v.9 no.6
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• pp.726-731
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• 1999

It was discovered that ammonium phosphate in the medium played an important role in both growing mycelium and producing exopolysaccharides (EPS) from G. lucidum. In lower concentration levels of ammonium phosphate (0-3 g/l), an improved mycelial growth was observed by maintaining more filamentous morphology than in high concentrations (5-11 g/l). In addition, it was confirmed by comparing the factual dimension and frequency of the area regarding the mycelial pellets. This must be attributed to limitations of nutrient transfer by maintaining filamentous mycelium during the cultivation in a low ammonium phosphate containing medium. On the other hand, the best EPS production was observed in medium with the absence or low concentration of ammonium phosphate. The shear stress of the culture broth was greatly affected by the shear rate, as compared with that of the culture broth with high ammonium phosphate concentration. The rheological characteristics of the fermentation broth and filtrate worked well according to the Herschel-Bulkley model. It was also found that the morphological changes of the mycelium resulting from the ammonium phosphate concentration directly affected the rheological characteristics of the system and resulted in reversely affecting the EPS production levels. Based on these results, it can be concluded that delicate regulation of the ammonium phosphate concentration in the culture media should be provided in order to obtain optimal mycelial growth and/or EPS production.

• Food Science and Biotechnology
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• v.14 no.4
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• pp.518-522
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• 2005

Yogurt containing high ${\gamma}$-aminobutyric acid (GABA) was developed using lactic acid bacteria and germinated brown rice. Lactobacillus acidophilus, L. plantarum, and L. brevis OPY-1 strains were inoculated into Lactobacillus MRS broth for use as yogurt starter. After treatment with 5% monosodium glutamate in MRS broth, L. brevis OPY-1 strain isolated from Kimchi produced GABA concentration of 8,003.28 nmol/mL. Starter was inoculated into fermentation substrate mixture containing germinated brown rice extract and blend of powdered whole milk and skim milk. Samples were incubated, and viable cell colonies were counted. Highest number of lactic acid bacteria was reached between 16 and 20 hr. Concentrated rice milk fermented with high GABA-producing strain contained GABA concentrations of $137.17\;{\mu}g/g$ D.W., whereas concentrated fermented milk prepared by conventional method contained GABA of $1.29\;{\mu}g/g$ D.W. Sensory evaluation panelists gave favorable ratings to fermented rice milk containing high GABA concentration.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.1030-1034
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• 2009

A fermenting microorganism involved in formation of ortho-dihydroxyisoflavones (ODIs) during aging of doenjang (Korean fermented soybean paste) has been investigated. Microorganisms in ODI-containing doenjang were isolated by cultivating on yeast mold (YM) agar medium containing 0-7% NaCl. ODI formation of the isolated strains was examined by gas chromatography/mass spectrometry (GC/MS) analysis after cultivation in modified YM broth or soybean extract medium. An ODI-producing microbe was identified as Bacillus subtilis HS-1 based on 16S rRNA gene sequence analysis. The strain has produced 8-hydroxydaidzein as a major product during growth in the modified YM broth or soybean extract medium. Therefore, it was concluded that one of the microorganisms involved in the formation of ODIs in doenjang was B. subtilis HS-1.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.8
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• pp.1170-1178
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• 2001

This study was conducted to isolate lactobacilli having characteristics to be used as health adjuncts with fermented milk products. Acid tolerant strains were selected in Lactobacilli MRS broth adjusted to pH 4.0 from human faeces. Bile tolerant strains were examined in Lactobacilli MRS broth in which 1.0% bile salt was added. Microhemagglutination tests using swine erythrocytes were performed to select lactobacilli having adherence properties to survive in the intestinal tract. By examination of these characteristics the strain Nam 27, which was isolated from adult faeces, was selected and identified as Lactobacillus salivarius subsp. salivarius based on carbohydrate fermentation and 16S rDNA sequencing.

• KSBB Journal
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• v.17 no.6
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• pp.566-570
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• 2002

In lactic acid fermentation, the end product inhibition by lactic acid causes several problems. The most important of which are low lactate formation rate and its recovery from fermentation broth. To overcome these problems, extractive lactic acid fermentation was carried out in a bioreactor, which was connected to a column packed with anion exchange resin (Amberlite IRA-400, 250 g). The system was started as a batch process, and then the separation process was started when the lactic acid concentration reached 10 g/L, 20 g/L or 30 g/L. In each case, total lactic acid concentration was reached to 48.6, 53.6, 52.6 g/L with its productivity of 1.2 g/L $.$ h, 1.6 g/L $.$ h, and 1.3 g/L $.$ h, respectively Especially, in the case of the 20 g/L recycling-initiation process, extractive fermentation reduced tie fermentation time (17 hrs) by 34% in comparison with the conventional batch process. The direct consequence of this time reduction was shown by a 1.8 fold increase in overall lactic acid productivity.

• Korean Journal of Medicinal Crop Science
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• v.18 no.6
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• pp.429-438
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• 2010

The use of cellulolytic lactic acid bacteria in new method to prepare high nutrition complementary foods was investigated. For the screening of cellulolytic lactic acid bacteria, more than 1,150 bacterial colony were isolated from diluted infant feces samples. A typical strain which appeared the most excellent cellulolytic activities was identified novel acidophilic Enterococcus sp. TO-94 through the results of morphological, biochemical and chemotaxonomic characteristics and 16S rDNA sequencing. The optimal lactic acid fermentation conditions of Omija(Schizandra chinensis Baillon) by Enterococcus sp. TO-94 were as follows: pH and temperature were 3.0 and $37^{\circ}C$, respectively, and fermentation time was 20hrs. The fructose and glucose were major free sugar and the contents were 5.83 and 4.30 mg/g after fermentation, respectively. The contents of lactic acid and acetic acid were 9.84 mg/g and 2.08 mg/g after fermentation, respectively. The vitamin $B_1$, $B_2$, niacin, folic acid and C were major vitamin in the fermented broth, the contents were 1.5~3 times higher than those of initial fermentation time. Also, the contents of polyphenol and anthocyanine were 3.8 and 1.2 times higher than those of initial fermentation time.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.4
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• pp.305-311
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• 1993

Marine organisms were investigated to identify the marine actinomycetes that produced noble bioactive compounds. Microorganism counts range from $2.1{\times}10^3\;to\;1.2{\times}10\;CFU/g$ of marine organisms. Actinomycetes constituted 0.01 to $0.5\%$ of culturable microbial community. We identified the marine actinomycetes that produced novel bioactive compounds. During the course of screening for bioactives from the marine microorganisms, we found that the strain in sponge had antimicrobial activities. From the morphological, cultural and various physiological characteristics, this strain was identified for Actinomycetes No. 101. The optimal compositions of culture medium for Actinomycetes No. 101 were starch 30g/l as carbon source, casamino acid 10g/l as nitrogen source. The optimal pH of medium and fermentation temperature were $6.5{\sim}7.0$ and $30^{\circ}C$, respectively. Fermentation has been conducted in the marine broth at $30^{\circ}C$ for 72 hour. The yield of fermentation got about 3g as dry weight(per liter of broth). The distribution of antimicrobial activity of Actinomycetes No. 101 was screened by paper disc. The extract of cultured cell and broth inhibited the growth of Staphylococcus aureus and Bacillus subtilis, but the inhibition action was week against yeast and mold.

• KSBB Journal
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• v.10 no.5
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• pp.568-574
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• 1995

To investigate the effect of pH on organic acid production by Anaerobiospirillum succiniciproducens, an anaerobic fermentation was carried out by maintaining the pH of the fermentation broth at 5.8, 6.0, 6.4, 6.8, and 7.2. At various pHs, the concentrations of cell were $1.0∼1.9g/\ell$ which were two to three times higher than those of the other worker's results, and the maximum was obtained at pH 5.8. Substrate consumption was increased by increasing the pH in the range of pH 6.0 to 6.8, while the sugar consumption rate at both pH 5.8 and 7.2 was very slow. The total amount of 2M $Na_2C0_3$ added for adjustment of pH change due to organic acid production was maximum at pH 6.8. Changes of conductivity of the fermentation broth was very simillar to those of 2M $Na_2C0_3$ added at various pHs. Therefore, it is suggested that determination of the amount of organic acid in a broth can be possible by measuring the conductivity. The maximum production yield of lactate based on glucose was 64% for pH 7.2 and 32% for pH 6.8, respectively.

• Journal of Life Science
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• v.18 no.8
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• pp.1049-1052
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• 2008

Microbial production of cellulolytic enzymes by Aspergillus niger in solid state fermentation (SSF) and submerged state fermentation (SF) in laboratory scale was compared. Czapek Dox liquid broth amended with cellulose (0.5%) was used for cultivation in SF, whereas rice bran was used as a solid support, moistened with cellulose, amended Czapek Dox broth for growth in SSF. The production of Carboxymethyl cellulase, Filter paperase and ${\beta}$-Glucosidase was monitored at regular intervals. The peak production of the enzymes occurred within 3 days of incubation in SSF as against $\geq$ 7 days in SF. SSF gave higher yields of enzymes in comparison to SF. Maximum titres of 0.40, 0.62 and 0.013 U/ml in respect of FPase, CMCase and ${\beta}$-glucosidase in SSF were recovered as against 0.13, 0.06 and 0.0013 U/ml in SF respectively, at their respective peak time intervals. Hence, SSF appeared to be a better choice for production of cellulolytic enzymes by Aspergillus niger.