Vesicular transport and secretion of penicillin G in Penicillium rubens P2-32-T.

The compartmentalization of penicillin G biosynthesis in Penicillium rubens has been extensively studied. However, how this compound is secreted has not been completely elucidated, although its transport could be of the vesicular type. This work was aimed at observing vesicles and penicillin secretion and proposing a hypothetical model for their compartmentalization and secretion. For this purpose, a high-penicillin-producing strain (P. rubens P2-32-T) was compared by transmission electron microscopy (TEM) and atomic force microscopy (AFM) with a null-producing strain (P. rubens npe10) in 24- and 48-h cultures. The results showed multivesicular bodies and secretory vesicles, suggesting that P. rubens transports and secretes penicillin G through vesicular excretion.