Evolution and Genetic Engineering - Bioprocess Engineering: Kinetics, Biosystems, Sustainability and Reactor Design - page 733

TABLE 14.8 Minimum Laboratory Containment Standards for Working with Cells with Recombinant DNA

Biosafety Level 1 (BL1)

1. Standard microbiological practices
a. Access to the laboratory is limited or restricted at the discretion of the laboratory director when
experiments are in progress.
b. Work surfaces are decontaminated once a day and after any spill of viable material.
c. All contaminated liquid or solid wastes are decontaminated before disposal.
d. Mechanical pipetting devices are used; mouth pipetting is prohibited.
e. Eating, drinking, smoking, and applying cosmetics are not permitted in the work area. Food may be stored
in cabinets or refrigerators designated and used for this purpose only.
f. Persons wash their hands after they handle materials involving organisms containing recombinant DNA
molecules, animals, and before leaving the laboratory.
g. All procedures are performed carefully to minimize the creation of aerosols.
h. It is recommended that laboratory coats, gowns, or uniforms be worn to prevent contamination or soiling
of street clothes.

2. Special practices
a. Contaminated materials that are to be decontaminated at a site away from the laboratory are placed in
a durable, leakproof container that is closed before being removed from the laboratory.
b. An insect and rodent control program is in effect.

3. Containment equipment
a. Special containment equipment is generally not required for manipulations of agents assigned to biosafety
level.

4. Laboratory facilities
a. The laboratory is designed so that it can be easily cleaned.
b. Bench tops are impervious to water and resistant to acids, alkalis, organic solvents, and moderate heat.
c. Laboratory furniture is sturdy. Spaces between benches, cabinets, and equipment are accessible for
cleaning.
d. Each laboratory contains a sink for handwashing.
e. If the laboratory has windows that open, they are fitted with fly screens.

The degree of containment required depends on (1) the ability for the host to survive if
released, (2) the ability for the vector to cross species lines or for a cell to be transformed
by a piece of naked DNA and then have it incorporated into the chromosome via recom-
bination, and (3) the nature of the genes and gene products being engineered. Experiments
involving overproduction of E. coli proteins in E. coli using plasmids derived from wild
populations are readily approved and do not require elaborate containment procedures
(see Table 14 .8 ). Experiments that would move the capacity to produce a toxin from
a higher organism into bacteria or yeast would be subjected to a much more thorough
evaluation, and more elaborate control facilities and procedures would be required.
The National Institutes of Health (NIH) have guidelines that regulate the use of recombi-
nant DNA technology. Special regulations apply to large-scale systems (defined as 10 L).

There are three different levels of containment: BLl-LS, BL2-LS, and BL3-LS. BLl-LS (biosafety
level 1, large-scale) is the least stringent. Table 14.9 compares the requirements for the three
containment levels.
In all cases, no viable organisms can be purposely released. Gas vented from the fermenter
must be filtered and sterilized. All cells in the liquid effluent must be killed. The latter can

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