Environmental Engineering Reference
In-Depth Information
industrialsubmerged bioprocess for antibiotic production using near-infrared spectroscopy
,
Biotechnol Prog 16:1098-1105.
[40]
Chen, H. J., M. P. DeLisa, H. L. Cha, W. A. Weigand, G. Rao, and W. E. Bentley
(2000).
Framework for on-line optimization of recombinant protein expression in high-
celldensity E. coli cultures using GFP-fusion monitoring
, Biotechnol Bioeng 69:275-
285.
[41]
Li, J., S. Wang, W. J. Van Dusen, L. D. Schultz, H. A. George, W. K. Herber, H. J.
Chae, W. E. Bentley, and G. Rao (2000
). Green fluorescent protein in real-time studies
of the GAL1 promoter,
Biotechnol Bioeng 70:187-196.
[42]
Lubbert, A., and S. B. Jorgenson (2001).
Bioreactor performance: a more scientific
approach for practice,
J Biotechnol 85:187-212.
[43]
Agger, T., A. B. Spohr, and J. Nielsen (2001).
Alpha-amylase production in high cell
density submerged cultivations of Aspergillus oryzae,
Appl Microbiol Biotechnol 55:8
1- 84.
[44]
Straathof, A. J. J., S. Panke, and A. Schmid (2002).
The production of fine chemicals by
biotransformations,
Curr Opin Biotechnol 13:548-556.
C.
B
IOSEPARATIONS AND
B
IOPROCESSING
1. Introduction
The bioproducts considered in this report, primarily including materials either made by
living organisms or derived from biomass, typically require extraction from either a whole
organism, such as a plant; from aqueous bioreactor media (also referred to as fermentation
broth or culture media; or from downstream processing solutions. A prevalent challenge
presented by bioreactor-based processes, in particular, is the generation of products within
relatively dilute aqueous solutions. Bioreactor media usually must remain dilute, however, to
prevent inhibition of enzyme activity by accumulated products and to prevent cell mortality
due to accumulated wastes. Nevertheless, the design of bioreactors to allow higher solute
concentrations while maintaining cell health and activity is worthy of considerable effort.
Traditional separation techniques are well-developed, widely practiced, and
comprehensively described in standard references [1]. The techniques are categorized
according to their fundamental mechanisms as physical (adsorption, crystallization,
extraction, etc.), mechanical (filtration, centrifugation, etc.), thermal (distillation), or chemical
(chemisorption, chromatography). Because separations often dominate the economics of
biochemical processing, development of energy-efficient separation methods is of especially
great importance to the commercial success of the low-value, high-volume bioproducts most
relevant to pollution prevention.
Downstream processing of bioreactor contents involves special challenges due to the
presence of biomass and non-product biomolecules such as proteins and sugars, which
promote fouling (coverage with biofilms or clogging with bioparticles), and also due to the
necessarily dilute nature of fermentation broths, which causes the use of energy-intensive
distillation to be prohibitively expensive [1].
