Identification and Characterization of a Cellodextrin Transporter in Aspergillus niger

Abstract

Aspergillus niger produces a wide spectrum of extracellular polysaccharide hydrolases that hydrolyze cellulose into soluble glucose and cellodextrins. Transporters are essential for sugar uptake, yet it is not clear whether cellodextrin transporters exist in A. niger. Here, one cellulose inducible cellodextrin transporter CtA was identified in A. niger B2. It was found that CtA not only could transport cellobiose, but also cellotriose, cellotetraose, and cellopentaose. The yeast strain YPβG-CtA, expressing cellodextrin transporter CtA and an intracellular β-glucosidase, grew on cellobiose with the cell growth rate of 0.0830 ± 0.0113 h −1 under aerobic condition. Furthermore, the engineered yeast could produce 1.1 g/L ethanol anaerobically on cellobiose in 2 days. The identification of CtA provides evidence that the cellodextrin uptake is a complementary strategy of cellulose utilization in A. niger, and the CtA could be a strong transporter candidate for constructing engineered cellodextrin-utilizing microorganisms.

Reconstruction of a genome-scale metabolic model and in-silico flux analysis of Aspergillus tubingensis: a non-mycotoxinogenic citric acid-producing fungus

“…Certain novel plasma membrane transporters, which were absent in the latest A. niger models, were added to the model on the basis of recent literature. For instance, manganese [ 43 ], citrate [ 44 ] and cellodextrin [ 45 ] transporter reactions with corresponding genes were added. Mitochondrial shuttle proteins which transport citric acid from mitochondria to the cytosol in exchange for cytosolic organic acid are important to citric acid production in Aspergillus spp .…”

“…These include pathways for citramalate biosynthesis [ 38 ], glycine betaine biosynthesis [ 39 ], trans-4-hydroxy-L-pipecolic acid [ 40 ] and itaconate degradation [ 41 ]. Additionally, based on recent identifications, several transporters were added to the model, such as those for manganese [ 43 ], citrate [ 44 ] and cellodextrin [ 45 ] as well as mitochondrial citrate-oxoglutarate shuttle transporter [ 46 ]. The presence of the associated genes/proteins was manually checked in the genome of A. tubingensis .…”

Chemoenzymatic Syntheses of Fluorine-18-Labeled Disaccharides from [18F] FDG Yield Potent Sensors of Living Bacteria In Vivo

“…Several additional [ 18 F]-labeled disaccharides might be used to image important human pathogens in vivo . The unique metabolism of the α,α-1,1-linked disaccharide trehalose by Mycobacterium tuberculosis has been previously targeted for therapy and imaging. − The β-linked disaccharides laminaribiose and cellobiose could potentially be leveraged for the metabolic imaging of fungal infections given the presence of β-1,3 and β-1,4 linkages in β- d -glucans (BDG), found in the cell walls of fungi. − An existing clinical assay (serum and cerebrospinal fluid) detects fungal β-1,3 linkages via the coagulation cascade of the horseshoe crab to detect invasive fungal infections caused by Aspergillus and Candida species . With these potential imaging applications in mind, we attempted [ 18 F]-radiosyntheses of the additional disaccharides indicated in Figure A.…”

Assessing the intracellular primary metabolic profile of Trichoderma reesei and Aspergillus niger grown on different carbon sources

“…The assimilation and further catabolism of lactose in T. reesei is reported to be mediated by transporters anchored in the fungal surface and whose function might be also associated with the activation of its cellulolytic system ( Ivanova et al., 2013 ; Porciuncula et al., 2013 ; Zhang et al., 2013 ; Nogueira et al., 2018 ; Havukainen et al., 2020 ). Equivalently, a few lactose, galactose and other sugar transporters have been identified for A. niger ( Fekete et al., 2016 ; Peng et al., 2018 ; de Ruijter et al., 2020 ; Lin et al., 2020 ). Thus, our data give evidence that lactose was not only cleaved into glucose and galactose monomers as shown by the sugar quantification in the supernatant ( Figure S1 ), but it was also internalized to be assimilated into the fungal energy catabolism.…”