Lactobacillius Acidophilus reproduces using a process called binary fission. Binary fission begins with the DNA of the mother cell being duplicated and joining a circular structure, pair by pair. Each circular DNA strand then attaches to the plasma membrane. Near the place of attachment,the cell lengthens and causes the two replica chromosomes to split. At this time, the plasma membrane pinches inward toward the center of the cell. After it gets to the center, the cell separates into two daughter cells.

To see binary fission in action, click the link below:

http://www.youtube.com/watch?v=FcjAsTTN8qU

The process of binary fission is demonstrated below in the diagram below: