Beschreibung:
Nitrate ions (NO 3 − ) in wastewater are a major cause of pollution in aquatic environments worldwide. Magnetospirillum gryphiswaldense MSR-1 has a complete dissimilatory denitrification pathway, converts NO 3 − in water into nitrogen (N 2 ), and simultaneously removes ammonium ions (NH 4 + ). We investigated and confirmed direct effects of regulatory protein factors Mg2046 and MgFnr on MSR-1 denitrification pathway by EMSAs and ChIP-qPCR assays. Corresponding mutant strains were constructed. Denitrification efficiency in synthetic wastewater medium during a 12-h cell growth period was significantly higher for mutant strain Δmgfnr (28.26 mg·L −1 ·h −1 ) than for wild-type (22.42 mg·L −1 ·h −1 ). Presence of magnetic particles (magnetosomes) in MSR-1 greatly facilitates collection and isolation of bacterial cells (and activated sludge) by addition of a magnetic field. The easy separation of magnetotactic bacteria such as MSR-1 and Δ mgfnr from wastewater using magnetic fields is a unique feature that makes them promising candidates for practical application in wastewater treatment and sludge pretreatment