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the exclusion of all E_. coli K 1 2 research (approximately 80 percent of all 
recombinant DNA research in the U.S.) from the Guide! ines , except for 
those experiments over 10L. The Director elected to keep this research 
at P1-EK1 but did give full authority for its approval to the local IBC. 
At the RAC meeting of June 5-6, 1980, however, the RAC recommended 
approval of an amendment to the Guidelines which deleted the following 
phrase from Section 1-0-6, "We differentiate between small- and large- 
scale experiments with organisms containing recombinant DNAs because the 
probability of escape from containment barriers normally increases with 
increasing scale" by a vote of 14 yeas, 1 nay, and 3 abstentions. The 
nature of equipment used for large-volume fermentations is such that 
increases in volume do not pose any increase in the problem of contain- 
ment; if anything, the probability of hypothetical risk is diminished in 
proportion to the number of runs necessary to provide a target total 
volume per unit time. We commend the RAC on its acceptance of this 
! 
deletion. 
Commercial Scale Fermentation Procedures and Operator Training 
I would like to comment briefly on these large-scale procedures and 
the reliability of the systems. Although in recent years many technical 
changes have occurred in the age-old process of fermentation, the prin- 
ciples for fermentation of recombinant DNA organisms are essentially the 
same as those used for antibiotics since the 1950's. The basic equipment 
consists of closed stainless steel vessels designed, built, and tested to 
comply with pressure vessel codes. Such a vessel is normally fitted with 
an agitator to mix the contents and aid in aeration. Compressed air which 
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