• Journal of Microbiology and Biotechnology
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• v.33 no.8
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• pp.1023-1029
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• 2023

Biosurfactants reduce surface and interfacial tension due to their amphiphilic properties and are an eco-friendly alternative for chemical surfactants. In this study, a new yeast strain JAF-11 that produces a biosurfactant was selected using drop collapse method, and the properties of the extracts were investigated. The nucleotide sequences of the strain were compared with closely related strains and identified based on the D1/D2 domain of the large subunit ribosomal DNA (LSU) and internal transcribed spacer (ITS) regions. Neodothiora populina CPC 39399^T, the closest species with strain JAF-11, showed a sequence similarity of 97.75% for LSU and 94.27% for ITS, respectively. The result suggests that the strain JAF-11 represents a distinct species that cannot be assigned to any existing genus or species in the family Dothideaceae. Strain JAF-11 produced a biosurfactant reducing the surface tension of water from 72 mN/m to 34.5 mN/m on the sixth day of culture and the result of measuring the critical micelle concentration (CMC) by extracting the crude biosurfactant was found to be 24 mg/l. The molecular weight 502 of the purified biosurfactant was confirmed by measuring the fast atom bombardment mass spectrum. The chemical structure was analyzed by measuring ¹H nuclear magnetic resonance (NMR), ¹³C NMR, and two-dimensional NMRs of the compound. The molecular formula was C₂₆H₄₆O₉, and it was composed of one octanoyl group and two hexanoyl groups to myo-inositol moiety. The new biosurfactant is the first report of a compound produced by a new yeast strain, JAF-11.

• Journal of Microbiology and Biotechnology
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• v.23 no.7
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• pp.905-912
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• 2013

A novel species, Metschnikowia cibodasensis, is proposed to accommodate eight strains (ID03-$0093^T$, ID03-0094, ID03-0095, ID03-0096, ID03-0097, ID03-0098, ID03-0099, and ID03-0109) isolated from flowers of Saurauia pendula, Berberis nepalensis, and Brunfelsia americana in Cibodas Botanical Garden, West Java, Indonesia. The type strain of M. cibodasensis is ID03-$0093^T$ (= NBRC $101693^T$ =UICC $Y-335^T$ = BTCC-$Y25^T$). The common features of M. cibodasensis are a spherical to ellipsoidopedunculate shaped ascus, which contains one or two needle-shaped ascospores, and lyse at maturity. Asci generally develop directly from vegetative cells but sometimes from chlamydospores. The neighbor-joining tree based on the D1/D2 domain of nuclear large subunit (nLSU) ribosomal DNA sequences strongly supports that M. cibodasensis (eight strains) and its closest teleomorphic species, M. reukaufii, are different species by a 100% bootstrap value. The type strain of M. cibodasensis, ID03-$0093^T$, differed from M. reukaufii NBRC $1679^T$ by six nt (five substitutions and one deletion) in their D1/D2 region of nLSU rDNA, and by 18 nt (five deletions, four insertions, and nine substitutions) in their internal transcribed spacer regions of rDNA, respectively. Four strains representative of M. cibodasensis (ID03-$0093^T$, ID03-0095, ID03-0096, and ID03-0099) showed a mol% G+C content of $44.05{\pm}0.25%$, whereas that of M. reukaufii NBRC $1679^T$ was 41.3%. The low value of DNA-DNA homology (5-16%) in four strains of M. cibodasensis and M. reukaufii NBRC $1679^T$ strongly supported that these strains represent a distinct species.

• Korean Journal of Plant Taxonomy
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• v.49 no.3
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• pp.224-239
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• 2019

Species identification for the Korean tribe Desmodieae was conducted using the DNA barcoding genes rbcL, matK (from chloroplast DNA) and ITS (from nuclear ribosomal DNA). A total of 25 taxa (n = 75) in five genera were sequenced, and neighbor-joining trees were constructed using different combinations of DNA barcodes. When comparing these phylogenetic trees, a tree with all loci combined (rbcL + matK + ITS) showed the highest rate of identification success (72%). On this tree, two subtribes and five genera within the tribe were supported as monophyletic. In the Desmodiinae clade, Desmodium and Hylodesmum were more closely related to each other than to Ohwia. In the Hylodesmum clade, H. oldhamii was found to be a sister to H. podocarpum complex, and all taxa within the complex were identified successfully. Subsp. fallax, regarded as a variety of subsp. oxyphyllum, is closely clustered with subsp. podocarpum. Although var. mandshuricum has been regarded as a synonym of var. oxyphyllum, this taxon is supported as a distinct variety. For the Lespedezinae clade, all species of Kummerowia were monophyletic, while nine of 16 Lespedeza taxa were identified successfully. In particular, the resolution of Macrolespedeza (28.5%) was lower than that of Junceae (77.8%). Among the Lespedeza taxa, L. cuneata was distinguishable from L. lichiyuniae, despite morphological similarities. It has been suggested that both L. maritima and L. inschanica are hybrids. The former is thought to be an independent species. While it is difficult to determine whether the latter originated via hybridization, this study showed that it is closely related to L. juncea.