• KSBB Journal
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• v.15 no.6
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• pp.584-588
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• 2000

The optimum conditions for the production of an antifungal antibiotic from Bacillus sp. YJ-63 were investigated. The oprimumized medium consisted of 1.5% soluble starch, 1% tryptone and 0.5% yeast extract, and temperature and initial medium pH for production were optimal at 35$^{\circ}C$ and pH 6.0, respectively. Production yield was significantly improved by shaking culture using 50 ml medium in 500 ml flasks. Under these conditions, the production of the antifungal antibiotic was growth-dependent, from 35hrs into cultivation to the stationary phase and endospore formation.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1986.12a
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• pp.514.2-514
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• 1986

Since sisomicin which is produced by Micromonospora inyoensis is an intracellular antibiotic, the final antibiotic titer to be attained depends singnificantly on the cell mass in fermentation broth. Cobalt ion in medium was indispensable for getting a high antibiotic titer. However, in the presence of cobalt ion in medium, the antibiotic production proceeded up to about 4 days and thereafter stopped. From the experiments on theaddition of cobalt ion to culture medium, it was shown that the antibiotic production stopped due to the other physiological properties of cells rather than the accumulation of antibiotic in cells.

• KSBB Journal
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• v.6 no.1
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• pp.69-77
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• 1991

When S. fradiae was cultured in S medium, it stavted to produce neomycin in the middle of stationary phase of growth. Antibitoic production is regulated not only by glucose but also by metabolites formed from glucose. A chemically defined minimal salt broth was developen for the study of metabolites activating produition of antibiotic in a neomycin producer. When growth and production or antibiotic in minimal salt broth was examined with a full grown or a vefctativc mycelium, the medium was found not to be good for the growth, but to be good enough for the production of antibiotic with a full grown mycelium. When many carbotlydrates, organic acids, or alcohol were supplmented with instead of glucose in the medium suspcndcn with a full grown mycelium, the amount of antibiotic produced in the medium containing fumaratc was 5 times more than that in the medium with glucose. Further study indicated that the medium is not good also for the growth but good for the production of antibiotic. The antibiotic produced in this medium was identified to be neomycin. The activation of the production of neomycin by fumarate was further confirmed in a complex medium. Fuinarate is suspected to initiate and to activate the biosynthesis of neomycin at the gene level.

• Journal of Microbiology and Biotechnology
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• v.22 no.7
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• pp.939-946
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• 2012

Antibiotic production with Streptomyces sindenensis MTCC 8122 was optimized under submerged fermentation conditions by artificial neural network (ANN) coupled with genetic algorithm (GA) and Nelder-Mead downhill simplex (NMDS). Feed forward back-propagation ANN was trained to establish the mathematical relationship among the medium components and length of incubation period for achieving maximum antibiotic yield. The optimization strategy involved growing the culture with varying concentrations of various medium components for different incubation periods. Under non-optimized condition, antibiotic production was found to be $95{\mu}g/ml$, which nearly doubled ($176{\mu}g/ml$) with the ANN-GA optimization. ANN-NMDS optimization was found to be more efficacious, and maximum antibiotic production ($197{\mu}g/ml$) was obtained by cultivating the cells with (g/l) fructose 2.7602, $MgSO_4$ 1.2369, $(NH_4)_2PO_4$ 0.2742, DL-threonine 3.069%, and soyabean meal 1.952%, for 9.8531 days of incubation, which was roughly 12% higher than the yield obtained by ANN coupled with GA under the same conditions.

• YAKHAK HOEJI
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• v.35 no.3
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• pp.245-251
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• 1991

Selective culture of actinomycetes from soil microbes and their antibiotic producing characters by agar-disk method were examined. Some of the organisms which produced antibiotics on agar disk did not produce antibiotics in liquid culture. Further examination indicated that production of antibiotic was dependent on the composition of medium. Many streptomycestes produced antibacterial substances in tryptic soy broth but others produced antifungal antibiotics in V-8 broth. Production of antibacterial substances by Streptomyces sp. was also dependent on the medium composition.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.488-497
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• 1999

Probing Streptomyces albus ATCC 21838 chromosomal DNA with a proline tRNA sequence resulted in an isolation of a putative integrating element in the 6.4-kb EcoRI fragment. It was found that Streptomyces lividans TK-24 transformed with a cloned DNA fragment on a multicopy plasmid, produced a higher level of spore pigment and mycelial red pigment on a regeneration agar. Furthermore, the transformant S. lividans TK-24 produced a markedly increased level of undecylprodigiosin in a broth culture. A nucleotide sequence analysis of the cloned region revealed several open reading frames homologous to the integrases of integrating plasmids or temperate bacteriophages, signal-transducing regulatory proteins with a conserved ATP-binding domain, oxidoreductases ($\beta$-ketoacyl reductase), and an AraC-like transcriptional regulator. To examine the effect on antibiotic production, each coding region was overexpressed separately from the other genes in the region in S. lividans TK-24 with; pJHS3044 for the expression of the signal-transducing regulatory protein homologue, pJHS3045 for the homologue of oxidoreductase, and pJHS3051 for the homologue of the AraC-like transcriptional regulator. Phenotypic studies of S. lividans TK-24 strains harboring plasmids for the overexpression of individual genes suggested the following effects of the genes on antibiotic production: The oxidoreductase homologue stimulated the production of actinorhodin and undecylprodigiosin, which was influenced by the culture conditions; the homologue of the AraC-like transcriptional regulator was the most effective factor in antibiotic production within all the culture conditions tested; the signal-transducing regulatory protein homologue repressed the effect due to the homologue of the AraC-like transcriptional regulator, however, the antibiotic production was derepressed upon entering the stationary phase.

• Journal of Microbiology and Biotechnology
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• v.18 no.1
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• pp.128-134
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• 2008

The kinetics of cell growth and Cyclosporin A (Cyc A) production by Tolypocladium inflatum were studied in shake flasks and bioreactors under controlled and uncontrolled pH conditions. In the case of the shake flask, the production time was extended to 226 h and the maximal antibiotic concentration was 76 mg/l. When scaling up the cultivation process to a bioreactor level, the production time was reduced to only 70h with a significant increase in both the cell growth and the antibiotic production. The maximal dry cell weights in the case of the controlled pH and uncontrolled pH cultures in the bioreactor were 22.4g/l and 14.2g/l, respectively. The corresponding maximal dry cell weight values did not exceed 7.25g/l with the shake flask cultures. The maximal values for Cyc A production were 144.72 and 131.4 mg/l for the controlled and uncontrolled pH cultures, respectively. It is also worth noting that a significant reduction was observed in both the dry cell mass and the antibiotic concentration after the Cyc A production phase, whereas the highest rate of antibiotic degradation was observed in the stirred tank bioreactor with an uncontrolled pH. Morphological characterization of the micromorphological cell growth (mycelial/pellet forms) was also performed during cultivation in the bioreactor.

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.577-581
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• 2003

Streptomyces lividans is one of the most commonly-used streptomyetes strain as a molecular cloning and expression host. Unlike its close relative S. coelicolor, however, S. lividans rarely produces secondary metabolite such as actinorhodin in a typical glucose-containing culture condition due to insufficient expression of some antibiotic regulatory genes including afsR2. Although multiple copies of afsR2 or a glycerol-specific culture condition stimulated actinorhodin production in S. lividans, both failed to stimulate actinorhodin production in S. lividans cultured in a typical glucose-containing medium. To generate a culture-condition-independent actinorhodin-overproducing S. lividans strain the afsR2 gene was integrated into the S. lividans TK21 chromosome via homologous recombination, followed by the genetic confirmation. This S. lividans strain produced a significant amount of actinorhodin in both glucose-containing liquid and plate cultures, with higher actinorhodin productivity compared to the S. lividans containing multiple copies of afsR2. These results suggest that a chromosomal integration of a single copy of an antibiotic regulatory gene is a promising method for the development of a stable antibiotic-overproducing streptomycetes strain.

• Korean Journal of Veterinary Service
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• v.21 no.2
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• pp.149-156
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• 1998

The present study was carried out to investigate the biochemical characteristics, antibiotic susceptibility and toxin(ST, LT, VT1.2 type) production test of 60 Escherichia coli isolated from diseased domestic animals in southern area of Kyungbuk province from April to December 1997. 1. The biochemical and cultural reaction were consistent with the classification criteria of Edwards and Ewing. 2. In antibiotic susceptibility test, 60 E coli showed highly susceptible to CL(96.7%), XNL(86.7%), AN(81.7%), SXT(61.7%), Lin(55%), GM(53.3%), KM(41.7%), N(41.7%), ENR(40%), AM(40%), CF(30%), 5(13.3%) and Te(11.7%), in order. 3. Sixty E coli isolates were multiful resistant to seven or more antibiotics incombination. 4. Three strains for 60 E coli were detected heat-labile enterotoxin(LT) and that's titers were 2, 8 and 16, respectively.

• Journal of Microbiology and Biotechnology
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• v.21 no.12
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• pp.1294-1298
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• 2011

A metK gene encoding S-adenosyl-L-methionine synthetase was cloned from the non-Streptomyces actinomycetes, Actinoplanes teichomyceticus ATCC31121. In order to evaluate the effect of the metK expression on antibiotic production in actinomycetes, an expression vector harboring the metK gene was constructed and introduced into Streptomyces lividans TK24 and A. teichomyceticus, and the antibiotic production of the exconjugants was assessed. As a result, it was determined that the expression of metK induced 17-fold and 2.2-fold increases in actinorhodin production from S. lividans TK24 and teicoplanin production from A. teichomyceticus, respectively, compared with the control strains.