Should I use Ni-NTA Agarose in column or batch format for purification of 6xHis-tagged proteins?

The binding capacity of Ni-NTA Agarose is the same regardless of the format used. However, the batch procedure (mixing the Ni-NTA resin with lysate or protein sample prior to loading it onto a column, as opposed to loading the sample onto a column pre-packed with Ni-NTA resin) can provide more efficient binding for dilute proteins, since binding can be carried out for an extended period (approximately 1 hour), and resin amounts can be scaled for variable amounts of lysate/protein sample.