Functional characterization of a highly specific l-arabinose transporter from Trichoderma reesei
Year: 2021
Type: article
Abstract: Background Lignocellulose biomass has been investigated as a feedstock for second generation biofuels and other value-added products. Some of the processes for biofuel production utilize cellulases and hemicellulases to convert the lignocellulosic biomass into a range of soluble sugars before fermentation with microorganisms such as yeastSaccharomyces cerevisiae. One of these sugars isl-arabinose, which cannot be utilized naturally by yeast. The first step inl-arabinose catabolism is its transport into the cells, and yeast lacks a specific transporter, which could perform this task. Results We identified Trire2_104072 ofTrichoderma reeseias a potentiall-arabinose transporter based on its expression profile. This transporter was described already in 2007 asd-xylose transporter XLT1. Electrophysiology experiments withXenopus laevisoocytes and heterologous expression in yeast revealed that Trire2_104072 is a high-affinityl-arabinose symporter with aKmvalue in the range of $$\sim$$ ∼ 0.1–0.2 mM. It can also transportd-xylose but with low affinity (Km $$\sim$$ ∼ 9 mM). In yeast,l-arabinose transport was inhibited slightly byd-xylose but not byd-glucose in an assay with fivefold excess of the inhibiting sugar. Comparison with knownl-arabinose transporters revealed that the expression of Trire2_104072 enabled yeast to uptakel-arabinose at the highest rate in conditions with low extracellularl-arabinose concentration. Despite the high specificity of Trire2_104072 forl-arabinose, the growth of itsT. reeseideletion mutant was only affected at lowl-arabinose concentrations. Conclusions Due to its high affinity forl-arabinose and low inhibition byd-glucose ord-xylose, Trire2_104072 could serve as a good candidate for improving the existing pentose-utilizing yeast strains. The discovery of a highly specificl-arabinose transporter also adds to our knowledge of the primary metabolism ofT. reesei. The phenotype of the deletion strain suggests the involvement of other transporters inl-arabinose transport in this species.
Source: Microbial Cell Factories
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: gold
Estimated APC paid: $2,361
OpenAlex ID: W3198526188