A photo-direct printer apparatus which prints an image on the basis of image data from a digital camera, memory card, or PC serving as an image data source receives a control command from the image data source, interprets the control command, and receives image data from the image data source on the basis of the command. A next step includes growing fibers, each including carbon as a major component, based on the catalytic particles arranged on the substrate. The present invention also provides hot cells having a mutation or deletion of part or all of the gene encoding the metalloprotease.