84 



A MANUAL OF THE PENICILLIA 



Parasitization 



Some species of Penidllium parasitize the mycelia and fruiting struc- 

 tures of Aspergillus species and other saprophytic molds. Penidllium 



-%. 



4 j>\ 



:^#-^3^ 



Fig. 23. Penicillium sp. parasitic on Aspergillus niger, X 165. (Photograph by 

 Edward Yuill, Manual of The Aspergilli, Williams & Wilkins, 1945). 



rugulosum Thom and P. puvpurogenum Stoll in particular, are able to in- 

 fect, overgrow, and destroy cultures of Aspergillus niger, A. tamarii and 

 A. flavus. When such infections occur in fermentation processes, yields 

 of acid or other products may be greatly reduced. Cases of parasitism 

 between a Penicillium and a black Aspergillus are easy to demonstrate 

 (fig. 23). Other cases of intimate mixture or parasitism may be difficult 



