Biomedical Engineering Reference
In-Depth Information
The biotransformation process and engineering of lignocellulose are involved
in the need for industrialization and commercialization; they are the theory and
technology for cellulose conversion. The scope of study of the biotransformation
process and the engineering of lignocellulose include scale-up and scale-down,
integration, development of an ecological industry chain, as well as the process of
conversion technological economic analysis and the life cycle.
11.4.2
Research Methods for the Scale-Up and Scale-Down
of the Biotransformation Process and Engineering
of Lignocellulose
11.4.2.1
Research Methods for the Scale-Up
The production process for cellulose-based products is a complex network com-
posed of many devices, not the sum of the separate devices enlarged; there are
unpredictable problems that may be exposed because perfectly amplifying each
aspect does not mean that the whole process is scaled up.
The scale-up method for the biotransformation process is mainly the amplifica-
tion of the bioreactor. There are usually three stages in the research and development
of biological products: the laboratory, pilot, and industrialized-scale stages. The
biological reaction is same in the various stages, but the mixing of reaction solution,
the mass transfer, and the heat transfer often are not the same. It must be understood
how to estimate the state of biological responses in different scale bioreactors,
especially in the reactor amplification process, to maintain cell growth similar
to the biological response rate, to summarize the inherent law and influencing
factors through the application of theory and experiment, and to study and solve
the transfer of material and energy. The reactor amplification process as much as
possible maintains the original state of the reaction for the scaled-up bioreactor [
157
,
158
].
Theoretically, this scaled-up bioreactor is formed by the following three steps in
the development and design processes of the biological reaction and bioreactor:
(1) The cells are used in a wider culture condition to grasp the cell growth kinetics
and product formation kinetics.
(2) According to the series of tests mentioned, the optimum culture medium
formulations and culture conditions of the biological response are determined.
(3) Microbalance equations are solved for the quality, heat transfer, and momentum
transfer and the relational model between the environmental conditions and
the main operating variables (stirring rotational speed
n
, aeration amount
Q
,
stirring power
P
g
,matrixflowrate
V
, etc.) is derived. Then, this mathematical
model is applied to calculate the value of the main variables under the optimized
conditions.
