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Background   l -Arabinose occurs at economically relevant levels in lignocellulosic hydrolysates. Its low-affinity uptake via the  Saccharomyces cerevisiae  Gal2 galactose transporter is inhibited by  d -glucose. Especially at low concentrations of  l -arabinose, uptake is an important rate-controlling step in the complete conversion of these feedstocks by engineered pentose-metabolizing  S. cerevisiae  strains.    Results  Chemostat-based transcriptome analysis yielded 16 putative sugar transporter genes in the filamentous fungus  Penicillium chrysogenum  whose transcript levels were at least threefold higher in  l -arabinose-limited cultures than in  d -glucose-limited and ethanol-limited cultures. Of five genes, that encoded putative transport proteins and showed an over 30-fold higher transcript level in  l -arabinose-grown cultures compared to  d -glucose-grown cultures, only one (Pc20g01790) restored growth on  l -arabinose upon expression in an engineered  l -arabinose-fermenting  S. cerevisiae  strain in which the endogenous  l -arabinose transporter,  GAL2 , had been deleted. Sugar transport assays indicated that this fungal transporter, designated as  Pc AraT, is a high-affinity ( K  m  = 0.13 mM), high-specificity  l -arabinose-proton symporter that does not transport  d -xylose or  d -glucose. An  l -arabinose-metabolizing  S. cerevisiae  strain in which  GAL2  was replaced by  PcaraT  showed 450-fold lower residual substrate concentrations in  l -arabinose-limited chemostat cultures than a congenic strain in which  l -arabinose import depended on Gal2 (4.2 × 10 −3  and 1.8 g L −1 , respectively). Inhibition of  l -arabinose transport by the most abundant sugars in hydrolysates,  d -glucose and  d -xylose was far less pronounced than observed with Gal2. Expression of  Pc AraT in a hexose-phosphorylation-deficient,  l -arabinose-metabolizing  S. cerevisiae  strain enabled growth in media supplemented with both 20 g L −1   l -arabinose and 20 g L −1   d -glucose, which completely inhibited growth of a congenic strain in the same condition that depended on  l -arabinose transport via Gal2.    Conclusion  Its high affinity and specificity for  l -arabinose, combined with limited sensitivity to inhibition by  d -glucose and  d -xylose, make  Pc AraT a valuable transporter for application in metabolic engineering strategies aimed at engineering  S. cerevisiae  strains for efficient conversion of lignocellulosic hydrolysates.    Electronic supplementary material  The online version of this article (10.1186/s13068-018-1047-6) contains supplementary material, which is available to authorized users.

The Penicillium chrysogenum transporter PcAraT enables high-affinity, glucose-insensitive l-arabinose transport in Saccharomyces cerevisiae