• Journal of the Korean Society of Industry Convergence
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• v.2 no.1
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• pp.77-83
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• 1999

Grown in the secondary broth of production media, the strain Streptomyces albulus has increased more the production of its metabolite ${\varepsilon}$-poly-L-lysine, one of poly(amino acid)s used as disinfecting food additives, than the strain in the primary culture of growth nutrients. Having the strain removed, the large concentrate obtained by ultrafiltrating the secondary culture broth. The concentrated production broth exchanged into followed by detecting in UV flowcell at 220nm the peptide bond of the components eluting the adsorbed proteins and polylysine with NaCl salt of gradient concentration, and has separated into five components. Among them the component in the fourth peak fraction has proved to be the pure ${\varepsilon}$-poly-L-lysine after the portion being hydrolyzed the fraction with HCl into amino acid followed by being the composing amino acid analysis.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.417-420
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• 2005

Plants generally produce secondary metabolites in nature as a defense mechanism against pathogenic and insect attack. In this study, we applied several abiotic elicitors in order to enhance growth and ginseng saponin biosynthesis in the hairy roots of P. ginseng. Generally, elicitor treatments were found to inhibit the growth of the hairy roots, although simultaneously enhancing ginseng saponin biosynthesis. The addition of selenium at inoculum time did not significantly affect ginseng saponin biosynthesis. However, when 0.5 mM selenium was added as an elicitor after 21 days of culture, ginseng saponin content and productivity increased to about 1.31 and 1.33 times control levels, respectively. These results suggest that processing time for the generation of ginseng saponin in a hairy root culture can be reduced via the application of an elicitor.

• Journal of Industrial Technology
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• v.21 no.A
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• pp.343-349
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• 2001

This study characterizes the growth of white rot fungi Phanerochaete chrysosporium IFO 31249) and lignin peroxidase(LiP) activity in different submerged culture media. P. chrysosporium was grown in the form of pellet of various sizes from a spore inoculum under shaking liquid culture condition. While the growth of mycelia was higher under the nitrogen-sufficient culture than under the nitrogen-limited culture, ligninase activity was relatively lower. The lignin peroxidase appeared in nitrogen-limited culture and was suppressed by excess nitrogen. High level(40U/l) of lignin peroxidase activity was obtained in the growth medium containing 1.5mM veratryl alcohol, a secondary metabolite of P. chrysosporium. Lignin peroxidase production was not observed under conditions of nitrogen sufficiency or in balanced media, suggesting that control parameters could increase the activity by manipulating the secondary metabolism.

• Journal of Microbiology and Biotechnology
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• v.28 no.7
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• pp.1068-1077
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• 2018

DKxanthenes are a class of yellow secondary metabolites produced by myxobacterial genera Myxococcus and Stigmatella. We identified a putative 49.5 kb DKxanthene biosynthetic gene cluster from Myxococcus stipitatus DSM 14675 by genomic sequence and mutational analyses. The cluster consisted of 15 genes (MYSTI_06004-MYSTI_06018) encoding polyketide synthases, non-ribosomal peptide synthases, and proteins with unknown functions. Disruption of the genes by plasmid insertion resulted in defects in the production of yellow pigments. High-performance liquid chromatography and liquid chromatography-tandem mass spectrometry analyses indicated that the yellow pigments produced by M. stipitatus DSM 14675 might be novel DKxanthene derivatives. M. stipitatus did not require DKxanthenes for the formation of heat-resistant viable spores, unlike Myxococcus xanthus. Furthermore, DKxanthenes showed growth inhibitory activity against the fungi Aspergillus niger, Candida albicans, and Rhizopus stolonifer.

• Korean Journal of Pharmacognosy
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• v.52 no.4
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• pp.203-207
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• 2021

LC/MS approach targeting secondary metabolites of bacterial strain resulted in the discovery of boholamide A (1), from the culture of marine actinomycete strain which was isolated from a tidal mudflat in Muan, Republic of Korea. Boholamide A (1), a cyclodepsipeptide with HDMN, APD, glycine, and valine was structurally determined by using 1D/2D NMR spectroscopy, mass spectrometry and UV spectroscopy. Boholamide A (1) showed the inhibitory activity against Bacillus subtilis, with IC₅₀ value of 0.08 mM.

• Biomolecules & Therapeutics
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• v.27 no.2
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• pp.127-133
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• 2019

The study of the genus Streptomyces is of particular interest because it produces a wide array of clinically important bioactive molecules. The genomic sequencing of many Streptomyces species has revealed unusually large numbers of cytochrome P450 genes, which are involved in the biosynthesis of secondary metabolites. Many macrolide biosynthetic pathways are catalyzed by a series of enzymes in gene clusters including polyketide and non-ribosomal peptide synthesis. In general, Streptomyces P450 enzymes accelerate the final, post-polyketide synthesis steps to enhance the structural architecture of macrolide chemistry. In this review, we discuss the major Streptomyces P450 enzymes research focused on the biosynthetic processing of macrolide therapeutic agents, with an emphasis on their biochemical mechanisms and structural insights.

• Microbiology and Biotechnology Letters
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• v.49 no.1
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• pp.32-38
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• 2021

Tubulysins are a group of secondary metabolites produced by myxobacteria that inhibit the function of the eukayotic cytoskeleton. We developed a pair of PCR primers that specifically amplified tubulysin biosynthetic genes. Using these primers, eight out of the eighty-one strains of myxobacteria belonging to the Cystobacteraceae family that harbored putative tubulysin biosynthetic genes were screened through PCR analysis. The selected strains included two Archangium gephyra, two Stigmatella sp., two Vitiosangium cumulatum, and two unidentified myxobacteria. LC-MS analysis of the culture extracts from the selected strains revealed that A. gephyra KYC4066 produced putative tubulysin A and B.

• KSBB Journal
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• v.13 no.3
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• pp.251-258
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• 1998

A structured kinetic model is proposed to describe cell growth and secondary metabolite, flavone glycosides, synthesis in batch suspension culture of Scutellaria baicalensis G. The model has been developed by representing the physiological state of cell described as the activity and viability which can be estimated based on the culture fluorescence. In the model, three type of cells are considered; active-viable, nonactive-viable and dead cells. Viable cell weight could be determined based on the relative fluorescence intensity. The flavone glycosides could be produced by both active-viable and non-active viable cells with a different production rate. And the model includes the cell expansion due to glucose concentration and death phase which accounts for the release of intracellular secondary metabolite into medium. Dependent variables include substrate concentration(glucose), cell mass(dry cell weight and fresh cell weight), product concentration(flavone glycosides), activity and viability. Satisfactory agreement between the model and experimental data is obtained from shake flask culture of Scutellaria baicalensis G. The proposed model can predict the cell growth and flavone glycosides synthesis as well as intermediate materials.

• Journal of Microbiology and Biotechnology
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• v.16 no.12
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• pp.1841-1848
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• 2006

Insights into gene expression have the potential for improvement of antibiotic yield and the development of robust production hosts for use in recombinant biomolecule production. $Cubicin^{TM}$ (daptomycin for injection) is a recently approved antibiotic active against many Gram(+) pathogens, including those resistant to methicillin, vancomycin, and fluoroquinolones. Daptomycin is produced as a secondary metabolite by Streptomyces roseosporus. A 128 kb region of DNA including the daptomycin biosynthetic gene cluster (dpt) has been cloned. and sequenced. Using a selected array of nucleic acid probes representing this region, we compared the expression levels of the dpt genes between S. roseosporus wild-type (WT) and derived S. roseosporus high-producer of daptomycin (HP). We observed that the majority of the biosynthetic genes were upregulated in HP compared with WT; a total of 12 genes, including those encoding daptomycin synthetase, showed consistently and significantly higher expression levels, at least 5-fold, in HP compared with WT. In contrast, some genes, flanking the dpt cluster, were expressed at higher levels in the WT strain. The expression of housekeeping genes such as S. roseosporus rpsL, rpsG, and 16S (positive controls) and presumptive intergenic regions in the dpt cluster (negative control) were identical in the two strains. In addition, we compared transcription during the early, mid-log, and early-stationary phases of growth in the HP strain. The same set of genes was upregulated and downregulated under all conditions examined; housekeeping genes showed no relative change in expression level over the periods of growth tested. Analyses of this type would be of value in studies of strain improvement and also for the identification of gene regulation processes that are important for secondary metabolite production.

• Korean Journal of Plant Tissue Culture
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• v.22 no.4
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• pp.183-187
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• 1995

The relationship between the intracellular phosphate level and catharanthine production in hairy root cultures of Catharanthus roseus was investigated The growth of hairy root increased in proportion to the phosphate concentration in the growth medium. When hairy roots were cultured in a phosphate-free medium, the catharanthine content was increased to the highest level As the phosphate concentration in the medium was enhanced, the catharanthine content decreased proportionally. Hairy root cultures with elevated intracellular phosphate concentrations indicated that growth was proportional to the level of intracellular phosphate. Catharanthine production increased abruptly below an intracellular phosphate level of $100\;\mumoles/g$ dry wt. The intracellular phosphate level may play a key role in the regulation of growth and secondary metabolite production.