• Microbiology and Biotechnology Letters
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• v.13 no.3
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• pp.223-232
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• 1985

To find microorganisms of producing $\alpha$-amylase inhibitors, actinomycetes were isolated from soil samples that were collected at different locations in Korea and screened for enzyme inhibitory activity. A strain of these microbes had a high inhibitory activity and was identified as one of the genus Streptomyces by morphological, biochemical and physiological studies according to the methods of the International Streptomyces Project (ISP). The medium used consisted of 3 ％ corn starch, 0.2％ yeast extract and 0.8％ peptone (pH 7.0). When this strain was aerobically cultured in the medium on a rotary shaker, the highest inhibitory activity was obtained after four days. This inhibitor had inhibitory activities on various $\alpha$-amylases and glucoamylase, but not on $\beta$-amylase.

• Journal of Microbiology and Biotechnology
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• v.20 no.11
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• pp.1597-1602
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• 2010

Chitinase is one of the most important mycolytic enzymes with industrial significance. This enzyme is produced by a number of organisms including bacteria. In this study, we describe the optimization of media components with increased production of chitinase for the selected bacteria, Stenotrophomonas maltophilia, isolated from soil. Different components of the defined media responsible for influencing chitinase secretion by the bacterial isolate were screened using Plackett-Burman experimental design and were further optimized by Box-Behnken factorial design of response surface methodology in liquid culture. Maximum chitinase production was predicted in medium containing 4.94 g/l chitin, 5.56 g/l maltose, 0.62 g/l yeast extract, 1.33 g/l $KH_2PO_4$, and 0.65 g/l $MgSO_4{\cdot}7H_2O$ using response surface plots and the point prediction tool of the DESIGN EXPERT 7.1.6 (Stat-Ease, USA) software.

• Environmental Engineering Research
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• v.25 no.4
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• pp.561-570
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• 2020

In the present study, dye decolorizing bacteria were isolated from water and soil samples, collected from textile industries in Jodhpur province, India. Two bacterial species namely, Bacillus pumilis and Paenibacillus thiaminolyticus were screened and identified based on biochemical characterization. The degradation efficiency of these two microorganisms was compared through optimization of pH, incubation time, initial dye concentration and inoculum size. B. pumilis and P. thiominolyticus were able to degrade 61% and 67% Red HE3B, 81% and 75% Orange F2R, 49.7% and 44.2% Yellow ME4GL and 61.6% and 59.5% Blue RC CT dyes of 800mg/l concentration respectively. The optimum pH and time were found to be 8 within 24 hours. The FT-IR analysis confirmed that microorganisms were able to degrade toxic azo dyes into a non-toxic product as proved through structural modifications to analyze chemical functions in materials by detecting the vibrations that characterize chemical bonds. It is based on the absorption of infrared radiation by the microbial product. Therefore, Bacillus pumilis and Paenibacillus thiaminolyticus are a promising tool for decolorization of dyes due to its potential to effectively decolorize higher azo dye concentrations (10-800 mg/L) and can be exploited for bioremediation.

• Journal of Microbiology and Biotechnology
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• v.2 no.3
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• pp.183-188
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• 1992

A soil bacterium which produces raw starch-digesting $\beta$-amylase in culture medium, has been screened from soils. One strain, isolated and identified as Bacillus polymyxa No. 26, was selected as a $\beta$-amylase producing bacterium. Morphological and biological characteristics of the strain were found to be similar to those of a strain belonging to B. polymyxa. The electron microscopic observations of the bacterial vegetative cells and sporulated cells were extensively done to know the corelation between the enzyme synthesis and sporulation. When the bacterium was cultured on the appropriate media (3% dextrin, 0.3% beef extract, 0.5% polypeptone, 1% yeast extract and 0.3% NaCl at pH 7.0 for 4 days) raw starch-digestible $\beta$-amylase was produced extracellularly. This strain produced 130 units of $\beta$-amylase per ml in a culture medium containing 3% dextrin at $30^\circ{C}$. This value is compared to those of other $\beta$-amylase-producing strains. The optimum pH and temperature for crude enzymes were pH 6.5 to 7.0 and $50^\circ{C}$, respectively. The enzymes were stable between pH 5.5 and 9.0 for 30 min at $45^\circ{C}$.

• Journal of Microbiology and Biotechnology
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• v.16 no.2
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• pp.184-192
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• 2006

Six-hundred bacterial strains from human milk and milk from Sahiwal cows, Holstein Friesian cows, and buffaloes were screened for their ability to suppress phytopathogenic fungi under in vitro conditions. A consortium of 3 strains, viz., Bacillus lentimorbus B-30486 (B-30486), B. subtilis B-30487 (B-30487), and B. lentimorbus B-30488 (B-30488), isolated from Sahiwal cow milk resulted in better biological control and plant-growth promotion than single-strain treatments. For commercial-scale production of a bioinoculant, the solid-state fermentation of sugarcane agro-industrial residues, i.e., molasses, press mud, and spent wash, using the consortium of B-30486, B-30487, and B-30488, resulted in a value-added product, useful for enhancing plant growth. The application of the consortium to sugarcane fields infested with Fusarium moniliforme and Colletotrichum falcatum resulted in a reduction of mortality and significantly higher (P=0.05) plant height, number of tillers, and cane girth when compared with the control. Furthermore, under field conditions, the treatment of sugarcane with the consortium resulted in significantly (P=0.05) greater plant growth compared with nonbacterized plants. Accordingly, this is the first report on the effective use of bacteria isolated from milk for biological control and enhancing plant growth under field conditions. Furthormore, a solid-state fermentation technology was developed that facilitates the economic utilization of agro-industrial residues for environmental conservation and improving plant and soil health.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.135-135
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• 1998

To find an antagonist of Pythium ultimum, the causal agent of damping-off, numerous actinomycete strains were screened for in vitro inhibiting mycelial growth of the target fungus and producing bioactive metabolites. A strain identified as Streptomyces sp. G60655 was isolated and used for further antagonistic efficacy. The degree of antagonism between the fungus and G60655 was affected by the medium used. Furthermore, the preinoculation of the antagonist was found to be necessary to exhibit the maximum efficacy of antagonsim against the fungus. From the culture broth, a bioactive metabolite was detected and purified by solvent extraction, silica gel chromatography and preparative HPLC. The FAB-MS spectrum of the active compound showed a molecular ion peak at m/z 1101 (M + H)$\^$+/, suggesting the molecular weight of 1100. The UV absorptions at 242 and 323 nm indicated the presence of aromatic functions. The structure of this compound was identified as echinomycin, a depsipeptide antibiotic by spectroscopic studies including various NMR measurements. Echinomycin was inactive against several soil born fungi, but inhibited the mycelial growth of P. ultimum and its related oomycetous fungi.

• Journal of Microbiology
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• v.44 no.4
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• pp.432-438
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• 2006

Twelve actinomycete strains were isolated from Egyptian soil. The isolated actinomycete strains were then screened with regard to their potential to generate antibiotics. The most potent of the producer strains was selected and identified. The cultural and physiological characteristics of the strain identified. the strain as a member of the genus Streptomyces. The nucleotide sequence of the 16S rRNA gene (1.5kb) of the most potent strain evidenced a 99% similarity with Streptomyces spp. and S. aureofaciens 16S rRNA genes, and the isolated strain was ultimately identified as Streptomyces sp. MAR01. The extraction of the fermentation broth of this strain resulted in the isolation of one major compound, which was active in vitro against gram-positive, gram-negative representatives and Candida albicans. The chemical structure of this bioactive compound was elucidated based on the spectroscopic data obtained from the application of MS, IR, UV, $^1H$ NMR, $^{13}C$ NMR, and elemental analysis techniques. Via comparison to the reference data in the relevant literature and in the database search, this antibiotic, which had a molecular formula of $C_{19}H_{29}NO_2$ and a molecular weight of 303.44, was determined to differ from those produced by this genus as well as the available known antibiotics. Therefore, this antibiotic was designated Meroparamycin.

• KSBB Journal
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• v.13 no.2
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• pp.220-222
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• 1998

Three microbial consortia were screened for their ability to degrade phenolic resin, resole as a sole carbon source. These microbial consortia were derived from soil samples collected from a phenolic resin manufacturing plant site. Among the consortia, the test consortium, designated as MS2, displayed approximately 70% degradation of the substrate, 100 mg of resole per liter, within the fist twelve days of incubation but the degradation was inhibited. During the incubation period, pH was decreased from 7.0 to 2.7, and the resole degradation became inhibited under the conditions. UV-scans of spent culture showed that the wavelength of maximum absorption was 261 nm for resole.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.1
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• pp.109-114
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• 2006

For the purpose of oligosaccharide production from alginate, the main component in cell walls of brown algae, the alginate degrading bacteria have been screened from the seaweeds and soil. Among the isolated 69 strains, one strain showing the highest degrading activity was selected and identified as Bacillus licheniformis strain. The adequate sodium alginate concentration for growing the Bacillus licheniformis was $2.0\%$. The effective nitrogen source is nutrient broth $(0.1\%)$, and optimum initial pH, NaCl concentration, temperature and incubation time to produce the alginate degrading enzyme were 7.5, $2\%,\;30{\pm}2^{\circ}C$, and 144 hrs, respectively.

• KSBB Journal
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• v.26 no.5
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• pp.465-470
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• 2011

Twenty six microorganisms were isolated from soil and horse manure samples from in Iowa, U.S. Microorganisms were cultivated and screened by using plate count agar (PCA) at $35^{\circ}C$ containing 1% (w/v) oat spelt xylan instead of glucose. The xylanase activities of bacterial strains were analyzed by measuring the concentration of reducing sugar by DNS method. All isolated strains were characterized as the rod form and gram positive strains. Among the isolated strains, the HM6 strains gave the highest xylanase activity. This strain was identified as Bacillus pumilus HM6 by 16S rDNA sequence, morphological and biochemical analysis. Optimal culture temperature and initial medium pH for B. pumilus HM6 were $30-35^{\circ}C$ and pH 6-7, respectively. The maximum xylanase activity of 6879 IU/mL was obtained after growth of HM6 with 1% (w/v) oat spelt xylan at $35^{\circ}C$ for 6 days. Studies on enzymatic properties showed that the optimum conditions for the highest xylanase activity were $60^{\circ}C$ and pH 8.0. In addition, xylanase activity was stable over 2 hours at $50^{\circ}C$, whereas activity decreased after 30 min at $70^{\circ}C$.