Transformation of sugarcane molasses into fructooligosaccharides with enhanced prebiotic activity using whole-cell biocatalysts from Aureobasidium pullulans FRR 5284 and an invertase-deficient Saccharomyces cerevisiae 1403-7A
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SUBMITTER: Khatun M
PROVIDER: S-EPMC10992603 | biostudies-literature | 2021 Sep
REPOSITORIES: biostudies-literature
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Project description:BackgroundPolymalic acid (PMA) is a water-soluble biopolymer with many attractive properties for food and pharmaceutical applications mainly produced by the yeast-like fungus Aureobasidium pullulans. Acid hydrolysis of PMA, resulting in release of the monomer l-malic acid (MA), which is widely used in the food and chemical industry, is a competitive process for producing bio-based platform chemicals.ResultsIn this study, the production of PMA and MA from sucrose and sugarcane molasses by A. pullulans was studied in shake flasks and bioreactors. Comparative metabolome analysis of sucrose- and glucose-based fermentation identified 81 intracellular metabolites and demonstrated that pyruvate from the glycolysis pathway may be a key metabolite affecting PMA synthesis. In silico simulation of a genome-scale metabolic model (iZX637) further verified that pyruvate carboxylase (pyc) via the reductive tricarboxylic acid cycle strengthened carbon flux for PMA synthesis. Therefore, an engineered strain, FJ-PYC, was constructed by overexpressing the pyc gene, which increased the PMA titer by 15.1% compared with that from the wild-type strain in a 5-L stirred-tank fermentor. Sugarcane molasses can be used as an economical substrate without any pretreatment or nutrient supplementation. Using fed-batch fermentation of FJ-PYC, we obtained the highest PMA titers (81.5, 94.2 g/L of MA after hydrolysis) in 140 h with a corresponding MA yield of 0.62 g/g and productivity of 0.67 g/L h.ConclusionsWe showed that integrated metabolome- and genome-scale model analyses were an effective approach for engineering the metabolic node for PMA synthesis, and also developed an economical and green process for PMA and MA production from renewable biomass feedstocks.
| S-EPMC5883625 | biostudies-literature
Project description:In an attempt to enhance the value of sugarcane leaf, xylan was extracted and used for xylooligosaccharide (XO) production via enzymatic hydrolysis using xylanase from the black yeast Aureobasidium pullulans. The xylan was extracted from sugarcane leaf using alkali extraction according to the response surface methodology. The highest xylan yield (99.42 ± 4.05 % recovery) was obtained using 14.32 % (w/v) NaOH, 13.25:1 liquid: solid ratio, at 121 °C and 15 lb.in2 for 32 min. Sugar composition and FTIR spectrum analyses confirmed its structure as arabinoxylan. The extracted arabinoxylan had a relatively high molecular weight compared to previous studies. Crude endoxylanase from A. pullulans NRRL 58523 was selected for enzymatic hydrolysis of the xylan. The enzyme hydrolyzed well at 50 °C, pH 4.0 and was relatively stable under this condition (87.38 ± 1.26 % of the activity remained after 60 h). XOs, especially xylobiose and xylotriose, were obtained at the maximum yield of 237.51 ± 17.69 mg/g xylan via endoxylanase hydrolysis under the optimum conditions (50 °C, pH 4.0, 65.31 U/g xylan, 53 h). XOs exhibited species-specific prebiotic activity toward three strains of Lactobacillus spp. but not toward Bifidobacterium spp.
| S-EPMC10682688 | biostudies-literature
Project description: Not available
| S-EPMC10992317 | biostudies-literature
Project description:Using media with low water activity, a large numbers of aureobasidium-like black yeasts were isolated from glacial and subglacial ice of three polythermal glaciers from the coastal Arctic environment of Kongsfjorden (Svalbard, Spitsbergen), as well as from adjacent sea water, sea ice and glacial meltwaters. To characterise the genetic variability of Aureobasidium pullulans strains originating from the Arctic and strains originating pan-globally, a multilocus molecular analysis was performed, through rDNA (internal transcribed spacers, partial 28 S rDNA), and partial introns and exons of genes encoding beta-tubulin (TUB), translation elongation factor (EF1alpha) and elongase (ELO). Two globally ubiquitous varieties were distinguished: var. pullulans, occurring particularly in slightly osmotic substrates and in the phyllosphere; and var. melanogenum, mainly isolated from watery habitats. Both varieties were commonly isolated from the sampled Arctic habitats. However, some aureobasidium-like strains from subglacial ice from three different glaciers in Kongsfjorden (Svalbard, Spitsbergen), appeared to represent a new variety of A. pullulans. A strain from dolomitic marble in Namibia was found to belong to yet another variety. No molecular support has as yet been found for the previously described var. aubasidani. A partial elongase-encoding gene was successfully used as a phylogenetic marker at the (infra-)specific level.
| S-EPMC2610310 | biostudies-literature
Project description:BackgroundGinsenosides are Panax plant-derived triterpenoid with wide applications in cardiovascular protection and immunity-boosting. However, the saponins content of Panax plants is fairly low, making it time-consuming and unsustainable by direct extraction. Protopanaxadiol (PPD) is a common precursor of dammarane-type saponins, and its sufficient supply is necessary for the efficient synthesis of ginsenoside.ResultsIn this study, a combinational strategy was used for the construction of an efficient yeast cell factory for PPD production. Firstly, a PPD-producing strain was successfully constructed by modular engineering in Saccharomyces cerevisiae BY4742 at the multi-copy sites. Then, the INO2 gene, encoding a transcriptional activator of the phospholipid biosynthesis, was fine-tuned to promote the endoplasmic reticulum (ER) proliferation and improve the catalytic efficiency of ER-localized enzymes. To increase the metabolic flux of PPD, dynamic control, based on a carbon-source regulated promoter PHXT1, was introduced to repress the competition of sterols. Furthermore, the global transcription factor UPC2-1 was introduced to sterol homeostasis and up-regulate the MVA pathway, and the resulting strain BY-V achieved a PPD production of 78.13 ± 0.38 mg/g DCW (563.60 ± 1.65 mg/L). Finally, sugarcane molasses was used as an inexpensive substrate for the first time in PPD synthesis. The PPD titers reached 1.55 ± 0.02 and 15.88 ± 0.65 g/L in shake flasks and a 5-L bioreactor, respectively. To the best of our knowledge, these results were new records on PPD production.ConclusionThe high-level of PPD production in this study and the successful comprehensive utilization of low-cost carbon source -sugarcane molassesindicate that the constructed yeast cell factory is an excellent candidate strain for the production of high-value-added PPD and its derivativeswith great industrial potential.
| S-EPMC9636795 | biostudies-literature
Project description:Extracellular vesicles (EVs) are increasingly recognized as an important mechanism for cell-cell interactions. Their role in fungi is still poorly understood and they have been isolated from only a handful of species. Here, we isolated and characterized EVs from Aureobasidium pullulans, a biotechnologically important black yeast-like fungus that is increasingly used for biocontrol of phytopathogenic fungi and bacteria. After optimization of the isolation protocol, characterization of EVs from A. pullulans by transmission electron microscopy (TEM) revealed a typical cup-shaped morphology and different subpopulations of EVs. These results were confirmed by nanoparticle tracking analysis (NTA), which revealed that A. pullulans produced 6.1 × 10^8 nanoparticles per milliliter of culture medium. Proteomic analysis of EVs detected 642 proteins. A small fraction of them had signal peptides for secretion and transmembrane domains. Proteins characteristic of different synthesis pathways were found, suggesting that EVs are synthesized by multiple pathways in A. pullulans. Enrichment analysis using Gene Ontology showed that most of the proteins found in the EVs were associated with primary metabolism. When sequencing the small RNA fraction of A. pullulans EVs, we found two hypothetical novel mil-RNAs. Finally, we tested the biocontrol potential of EVs from A. pullulans. The EVs did not inhibit the germination of spores of three important phytopathogenic fungi – Botrytis cinerea, Colletotrichum acutatum, and Penicillium expansum. However, exposure of grown cultures of C. acutatum and P. expansum to A. pullulans EVs resulted in visible changes in morphology of colonies. These preliminary results suggest that EVs may be part of the antagonistic activity of A. pullulans, which is so far only partially understood. Thus, the first isolation and characterization of EVs from A. pullulans provides a starting point for further studies of EVs in the biotechnologically important traits of the biocontrol black fungus A. pullulans in particular and in the biological role of fungal EVs in general.
2022-11-09 | PXD037103 | Pride
Project description:Dimorphic fungus with industrial importance
| PRJNA161647 | ENA
Project description:Aureobasidium pullulans Transcriptome or Gene expression
| PRJNA1056143 | ENA
Project description:Aureobasidium pullulans Genome sequencing
| PRJNA950122 | ENA
Project description:Aureobasidium pullulans Genome sequencing and assembly of 50 environmental strains
| PRJNA488010 | ENA