Enhancement of magnetic particle production by nitrate and succinate fed-batch culture of Magnetospirillum sp. AMB-1

Magnetospirillum sp. AMB-1 is a magnetic bacterium, which is capable of growing under air atmosphere. This bacterium was employed to make bacterial magnetic particles (BMPs). AMB-1 only makes BMPs during logarithmic growth phase under anaerobic conditions. Since it requires nitrate as a nitrogen source, control of nitrate concentration in the medium was necessary. The fed-batch culture of AMB-1 was carried out by adding nitric acid and succinate as nitrogen and carbon source respectively. One liter of AMB-1 culture produced 0.34 g of dry cells and 4.5 mg of BMPs. BMP production by AMB-1 cultivated in the fed-batch culture was found to be seven times higher than that cultivated in the batch culture.