• 대한화학회지
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• 제62권1호
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• pp.64-67
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• 2018

• 한국식품과학회지
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• 제44권1호
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• pp.14-20
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• 2012

막걸리는 우리의 전통 주류이며, 최근 그 선호도가 높아지고 있음에도 불구하고 그에 함유된 성분들에 관한 체계적인 연구는 거의 전무한 실정이다. 그래서 막걸리에 함유된 항산화 활성화합물에 초점을 맞추어 column chromatography 및 HPLC를 행하여 화합물을 단리하고, 단리된 화합물들을 MS 및 NMR 분석을 행해 구조를 해석하였다. 그 결과 단리된 8종의 화합물을 4-hydroxybenzaldehyde(1), 2-(4-hydroxyphenyl)ethanol(2, tyrosol), trans-ferulic acid(3), cis-ferulic acid(4), 1H-indole-3-ethanol(5, tryptophol), dimethyl succinate(6), succinic acid(7), 그리고 mono-methyl succinate(8)로 동정하였다. 그리고 막걸리로부터 유기산들(화합물 6-8)의 존재가 보고된 바 있으나, 유기산 이외의 화합물 1-5는 본 연구에 의해 막걸리로부터 그 존재가 처음 밝혀졌다.

• Mycobiology
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• 제47권3호
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• pp.292-300
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• 2019

IAA biosynthetic pathways in a basidiomycetous yeast, Rhodosporidiobolus fluvialis DMKU-CP293, were investigated. The yeast strain showed tryptophan (Trp)-dependent IAA biosynthesis when grown in tryptophan supplemented mineral salt medium. Gas chromatography-mass spectrometry was used to further identify the pathway intermediates of Trpdependent IAA biosynthesis. The results indicated that the main intermediates produced by R. fluvialis DMKU-CP293 were tryptamine (TAM), indole-3-acetic acid (IAA), and tryptophol (TOL), whereas indole-3-pyruvic acid (IPA) was not found. However, supplementation of IPA to the culture medium resulted in IAA peak detection by high-performance liquid chromatography analysis of the culture supernatant. Key enzymes of three IAA biosynthetic routes, i.e., IPA, IAM and TAM were investigated to clarify the IAA biosynthetic pathways of R. fluvialis DMKU-CP293. Results indicated that the activities of tryptophan aminotransferase, tryptophan 2-monooxygenase, and tryptophan decarboxylase were observed in cell crude extract. Overall results suggested that IAA biosynthetic in this yeast strain mainly occurred via the IPA route. Nevertheless, IAM and TAM pathway might be involved in R. fluvialis DMKU-CP293.

• 한국미생물·생명공학회지
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• 제47권2호
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• pp.242-249
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• 2019

Biosynthesis of indole-3-acetate (IAA) from L-tryptophan via indole-3-pyruvate pathway requires three enzymes including aminotransferase, indole-3-pyruvate decarboxylase, and indole-3-acetate dehydrogenase. To establish a bio-based production of IAA, the aspC, ipdC, and iad1 from Escherichia coli, Enterobacter cloacae, and Ustilago maydis, respectively, were expressed under control of the tac, ilvC, and sod promoters in C. glutamicum. Cells harboring ipdC produced tryptophol, indicating that the ipdC product is functional in this host. Analyses of SDS-PAGE and enzyme activity revealed that genes encoding AspC and Iad1 were efficiently expressed from the sod promoter, and their enzyme activities were 5.8 and 168.5 nmol/min/mg-protein, respectively. The final resulting strain expressing aspC, ipdC, and iad1 produced 2.3 g/l and 7.3 g/l of IAA from 10 g/l L-tryptophan, respectively, in flask cultures and a 5-L bioreactor.

• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1726-1736
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• 2013

Biosynthesis of indole-3-acetic acid (IAA) via the indole-3-pyruvic acid pathway involves three kinds of enzymes; aminotransferase encoded by aspC, indole-3-pyruvic acid decarboxylase encoded by ipdC, and indole-3-acetic acid dehydrogenase encoded by iad1. The ipdC from Enterobacter cloacae ATCC 13047, aspC from Escherichia coli, and iad1 from Ustilago maydis were cloned and expressed under the control of the tac and sod promoters in E. coli. According to SDS-PAGE and enzyme activity, IpdC and Iad1 showed good expression under the control of $P_{tac}$, whereas AspC was efficiently expressed by $P_{sod}$ originating from Corynebacterium glutamicum. The activities of IpdC, AspC, and Iad1 from the crude extracts of recombinant E. coli Top 10 were 215.6, 5.7, and 272.1 nmol/min/mg-protein, respectively. The recombinant E. coli $DH5{\alpha}$ expressing IpdC, AspC, and Iad1 produced about 1.1 g/l of IAA and 0.13 g/l of tryptophol (TOL) after 48 h of cultivation in LB medium with 2 g/l tryptophan. To improve IAA production, a tnaA gene mediating indole formation from tryptophan was deleted. As a result, E. coli IAA68 with expression of the three genes produced 1.8 g/l of IAA, which is a 1.6-fold increase compared with wild-type $DH5{\alpha}$ harboring the same plasmids. Moreover, the complete conversion of tryptophan to IAA was achieved by E. coli IAA68. Finally, E. coli IAA68 produced 3.0 g/l of IAA after 24 h cultivation in LB medium supplemented with 4 g/l of tryptophan.