The effects of external Mn2+ concentration on hyphal morphology and citric acid production are mediated primarily by the NRAMP-family transporter DmtA in Aspergillus niger

Table 1 Specific Mn²⁺ intake in Aspergillus niger NRRL 2270, and the dmtA-deletion- and dmtA-overexpressing mutants

Strain	Specific Mn²⁺ ion uptake rate (pmoles min⁻¹ g⁻¹_DCW)
Strain	5 µg L⁻¹	100 µg L⁻¹	1000 µg L⁻¹
NRRL 2270	2.7 ± 0.2	10.0 ± 2.0	10.2 ± 2.9
∆dmtA	< 0.2	0.3 ± 0.1	3.6 ± 0.4
dmtA^OE	13.3 ± 1.5	22.0 ± 3.1	24.9 ± 5.5

Specific Mn²⁺ ion intake rates in Aspergillus niger NRRL 2270, wild type for the dmtA gene, and the dmtA-deleted and dmtA-overexpressing mutants at 5, 100 and 1000 µg L⁻¹ external Mn²⁺ ion concentrations. Biomass was generated on a medium with 5 µg L⁻¹ Mn²⁺ (i.e., under manganese limitation) and transferred to the test media to assess decrease of the external Mn²⁺ concentrations

ISSN: 1475-2859