Biomedical Engineering Reference
In-Depth Information
in SSL as a self-contained light source for plant growth. Applikon has cho-
sen to develop light panels that are add-on modules for our standard stirred
tank and single-use bioreactors. This offers maximum flexibility and a very
economical setup for cultivating photosynthesizing organisms. The volume
range covers 3 L up to 20 L autoclavable stirred-tank bioreactors and 10 up to
50 L single use bioreactors. SSL plant light has unique characteristics that are
useful for plant growth applications. An important characteristic is the spec-
tral distribution of light in the wavelengths region of 450-500 nm and 630-700
nm; these bands are critical for normal plant growth as they fall within the
photosynthetically active radiation, PAR, (400-700 nm), which plants primar-
ily use for biological processes and are also favorable for confined applica-
tions such as micropropagation.
Another useful characteristic is the long useful life of about 50,000 hours
and the high energy conversion efficiency. This results in substantially cooler
systems than other light sources. Systems also save energy by using less ven-
tilation and requiring less cooling for growing plants in the culture room.
Second, this provides new opportunities for enhancing growth of several
hard-to-grow plants or plants that require a specific range of light spectrum.
Stirred Single-Use Bioreactors
The stirred systems sold by Thermo Fisher Scientific and Xcellerex for use
with animal cells and for volumes up to 1,000 and 2,000 L offer challenges to
stainless steel bioreactors. Both of these bioreactors borrow their dimensions,
proportions, sparging systems, and mixing systems from the traditional
stainless steel systems. In reality, these are standard stainless steel systems
in which a liner has been installed. These bioreactors demonstrate that the
way to attract Big Pharma is to offer expensive big machines. For example,
the outer containers can be easily replaced with a much cheaper plastic shell
but that would make them less attractive and make it difficult to charge the
high price these systems command. There is no savings in capital investment
while there is a substantially higher expense involved in the ongoing cost to
operate these reactors. These reactors have also been converted to microbial
versions and evaluation by many large companies who would not mind pay-
ing the unjustified exorbitant prices of these reactors.
The BIOSTAT CultiBag STR of Sartorius-Stedim is a closed system and
demonstrates efficiencies close to reusable bioreactors. As an option,
the bag is equipped with a sparger ring or a microsparger and two axial
flow three-blade-segment impellers or a combination of one axial flow
three-blade-segment impeller and one radial flow six-blade-segment impel-
ler. Homogeneous mixing in the bag is achieved by the centered stirring
system.
