3 
Mr. Geoghegan suggested that Section VII-D-6 should be modified to read: 
"VII-D-6 . A closed system used for the propagation and growth 
of viable organisms containing recombinant D1& molecules shall be 
operated so that the space above the culture level be maintained 
at no more than 10 psig." 
Mr. Geoghegan argued that the proposed revision will permit fermentations more 
in line with industrial practices (high biomass production through efficient 
oxygen transfer) vhile not compromising safety by operating at unnecessarily 
high vessel pressures. 
Dr. West suggested it might be more appropriate to index pressure to some para- 
meter of the fermentation system, e.g., a fraction of the maximum working pres- 
sure of the vessel, or of the vessel and its ancillary equipment. Dr. Tolin 
agreed. Mr. Barbeito said verification that the equipment is designed to 
withstand 10 psig pressure should be required. He emphasized that the ancillary 
systems, such as filters, etc., must also withstand the pressure. Dr. West 
agreed that every component of the system should be tested and certified. 
Mr. Barbeito asked if negative pressure could provide the requisite quantity 
of oxygen aeration. Dr. McKinney said procedures utilizing negative pressure 
do not appear to work well. He felt Section VII-D-6 could be modified to permit 
some use of positive pressure, provided that the vessel is properly designed, 
and rated and certified to withstand the pressure. 
M01 
