Format

Send to

Choose Destination
Appl Environ Microbiol. 2015 Jun 15;81(12):4062-70. doi: 10.1128/AEM.00165-15. Epub 2015 Apr 3.

Functional Analysis of Two l-Arabinose Transporters from Filamentous Fungi Reveals Promising Characteristics for Improved Pentose Utilization in Saccharomyces cerevisiae.

Author information

1
Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China.
2
Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China College of Life Sciences, Hubei University, Wuhan, China.
3
Holzforschung München, TUM School of Life Sciences Weihenstephan, Technische Universität München, Freising, Germany benz@hfm.tum.de tian_cg@tib.cas.cn.
4
Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China benz@hfm.tum.de tian_cg@tib.cas.cn.

Abstract

Limited uptake is one of the bottlenecks for l-arabinose fermentation from lignocellulosic hydrolysates in engineered Saccharomyces cerevisiae. This study characterized two novel l-arabinose transporters, LAT-1 from Neurospora crassa and MtLAT-1 from Myceliophthora thermophila. Although the two proteins share high identity (about 83%), they display different substrate specificities. Sugar transport assays using the S. cerevisiae strain EBY.VW4000 indicated that LAT-1 accepts a broad substrate spectrum. In contrast, MtLAT-1 appeared much more specific for l-arabinose. Determination of the kinetic properties of both transporters revealed that the Km values of LAT-1 and MtLAT-1 for l-arabinose were 58.12 ± 4.06 mM and 29.39 ± 3.60 mM, respectively, with corresponding Vmax values of 116.7 ± 3.0 mmol/h/g dry cell weight (DCW) and 10.29 ± 0.35 mmol/h/g DCW, respectively. In addition, both transporters were found to use a proton-coupled symport mechanism and showed only partial inhibition by d-glucose during l-arabinose uptake. Moreover, LAT-1 and MtLAT-1 were expressed in the S. cerevisiae strain BSW2AP containing an l-arabinose metabolic pathway. Both recombinant strains exhibited much faster l-arabinose utilization, greater biomass accumulation, and higher ethanol production than the control strain. In conclusion, because of higher maximum velocities and reduced inhibition by d-glucose, the genes for the two characterized transporters are promising targets for improved l-arabinose utilization and fermentation in S. cerevisiae.

PMID:
25841015
PMCID:
PMC4524138
DOI:
10.1128/AEM.00165-15
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center