The yeast Yarrowia lipolytica secretes high amounts of various organic acids, like citric, isocitric, pyruvic (PA), and α-ketoglutaric (KGA) acids, triggered by growth limitation and excess of carbon source. This is leading to an increased interest in this non-conventional yeast for biotechnological applications. To improve the KGA production by Y. lipolytica for an industrial application, it is necessary to reduce the amounts of by-products, e.g., fumarate (FU) and PA, because production of by-products is a main disadvantage of the KGA production by this yeast. We have examined whether the concentration of secreted organic acids (main product KGA and PA as major by-product and FU, malate (MA), and succinate (SU) as minor by-products) can be influenced by a gene-dose-dependent overexpression of fumarase (FUM) or pyruvate carboxylase (PYC) genes under KGA production conditions. Recombinant Y. lipolytica strains were constructed, which harbor multiple copies of the respective FUM1, PYC1 or FUM1, and PYC1 genes. Overexpression of the genes FUM1 and PYC1 resulted in strongly increased specific enzyme activities during cultivation of these strains on raw glycerol as carbon source in bioreactors. The recombinant Y. lipolytica strains showed different product selectivity of the secreted organic acids KGA, PA, FU, MA, and SU. Concentrations of the by-products FU, MA, SU, and PA decreased significantly at overproduction of FUM and increased at overproduction of PYC and also of FUM and PYC simultaneously. In contrast, the production of KGA with the multicopy strains H355A(FUM1) and H355A(FUM1-PYC1) was comparable with the wild-type strain H355 or slightly lower in case of H355(PYC1). KGA productivity was not changed significantly compared with strain H355 whereas product selectivity of the main product KGA was increased in H355A(FUM1).
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http://dx.doi.org/10.1007/s00253-012-4085-1 | DOI Listing |
Nat Commun
January 2025
Department of Chemistry Education, Seoul National University, Seoul, Republic of Korea.
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January 2025
State Key Laboratory for Quality Ensurance and Sustainable Use of Dao-Di Herbs, Institute of Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing, 100700, China.
Background: Jianwei Xiaoshi oral liquid (JWXS), a classical traditional prescription comprising various edible medicinal plants, has demonstrated significant efficacy in treating paediatric indigestion. It originates from Jianpi Pill, which is developed in the Ming Dynasty and nourishes the spleen and regulates gastrointestinal function. However, the specific molecular mechanisms involved remain unclear.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
College of Materials Science and Engineering, Nanjing Tech University, Nanjing 211816, PR China. Electronic address:
The carboxymethyl chitosan (CMCS)-based porous beads are still criticized for their limited number of binding sites, which impairs their efficacy in removing aqueous pollutants. To overcome this challenge, this work introduces the production of covalently crosslinked CMCS-based beads containing SiO and poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS). The porous composite beads not only possess remarkable stability under acidic conditions, but also have abundant active binding sites for adsorption.
View Article and Find Full Text PDFTalanta
January 2025
College of Chemistry and Materials Science, Hunan Engineering Research Center for Monitoring and Treatment of Heavy Metals Pollution in the Upper Reaches of Xiangjiang River, Hengyang Normal University, Hengyang, 421001, China. Electronic address:
The accurate and sensitive quantification of hydroxyl radical (·OH) and glucose is necessary for disease diagnosis and health guidance, but still challenging owing to the low concentration of ·OH and poor water solubility of fluorescent probes. In addition, fluorescent probes may cause secondary pollution to the environment. Here an organic cage was reported as a sensitive fluorescent probe for ·OH and glucose in aqueous solution without serious secondary pollution.
View Article and Find Full Text PDFJ Nat Prod
January 2025
Department of Chemistry, Federal University of Piaui, Campus Ministro Petrônio Portela, Teresina, PI 64049-550, Brazil.
With praziquantel being the sole available drug for schistosomiasis, identifying novel anthelmintic agents is imperative. A chemical investigation of the fruiting body of the bioluminescent mushroom Berk. resulted in the isolation of new conjugated long-chain fatty acids (8,10,12,13)-12,13-dihydroxy-7-oxo-octadeca-8,10-dienoic acid () and (7,8,9,11)-7,8-dihydroxy-13-oxo-octadeca-9,11-dienoic acid () and three previously described compounds, (7,8,9)-7,8-dihydroxyoctadec-9-enoic acid (), (2)-dec-2-ene-1,10-dioic acid (), and a ketolactone marasmeno-1,15-dione ().
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