The 21st Annual Biochemical Engineering Symposium was held at Colorado State University on April 20, 1991. The primary goals of this symposium series are to provide an opportunity for students to present and publish their research work and to promote informal discussions on biochemical engineering research.

Contents
High Density Fed-Batch Cultivation and Energy Metabolism of Bacillus thuringtensis; W.-M. Liu, V. Bihari, M. Starzak, and R.K. Bajpai

Influences of Medium Composition and Cultivation Conditions on Recombinant Protein Production by Bacillus subtilis; K. Park, P.M. Linzmaier, and K.F. Reardon

Characterization of a Foreign Gene Expression in a Recombinant T7 Expression System Infected with λ Phages; F. Miao and D.S. Kompala

Simulation of an Enzymatic Membrane System with Forced Periodic Supply of Substrate; N. Nakaiwa, M. Yashima, L.T. Fan, and T. Ohmori

Batch Extraction of Dilut Acids in a Hollow Fiber Module; D.G. O'Brien and C.E. Glatz

Evaluation of a New Electrophoretic Device for Protein Purification; M.-J. Juang and R.G. Harrison

Crossflow Microfiltration and Membrane Fouling for Yeast Cell Suspension; S. Redkar and R. Davis

Interaction of MBP-β-Galactosidase Fusion Protein with Starch; L. Taladriz and Z. Nikolov

Predicting the Solubility of Recombinant Proteins in Escherichia coli; D.L. Wilkinson and R.G. Harrison

Evolution of a Phase-Separated, Gravity-Independent Bioractor; P.E. Villeneuve and E.H. Dunlop

A Strategy for the Decontamination of Soils Containing Elevated Levels of PCP; S. Ghoshal, S. K. Banelji, and RK. Bajpai

Practical Considerations for Implementation of a Field Scale In-Situ Bioremediation Project; J.P. McDonald, CA Baldwin, and L.E. Erickson

Parametric Sensitivity Studies of Rhizopus oligosporus Solid Substrate Fermentation; J. Sargantanis, M.N. Karim, and V.G. Murphy, and RP. Tengerdy

Production of Acetyl-Xylan Esterase from Aspergillus niger; M.R Samara and J.C. Linden

Biological and Latex Particle Partitioning in Aqueous Two-Phase Systems; D.T.L. Hawker, RH. Davis, P.W. Todd, and R Lawson

Novel Bioreactor /Separator for Microbial Desulfurization of Coal; H. Gecol, RH. Davis, and J .R Mattoon

Effect of Plants and Trees on the Fate, Transport and Biodegradation of Contaminants in the Soil and Ground Water; W. Huang, E. Lee, J.F. Shimp, L.C. Davis, L.E. Erickson, and J.C. Tracy

Sound Production by Interfacial Effects in Airlift Reactors; J. Hua, T.-Y. Yiin, LA Glasgow, and L.E. Erickson

Soy Yogurt Fermentation of Rapid Hydration Hydrothermal Cooked Soy Milk; P. Tuitemwong, L.E. Erickson, and D.Y.C. Fung

Influence of Carbon Source on Pentachlorophenol Degradation by Phanerochaete chrysosportum in Soil; C.-Y.M. Hsieh, RK. Bajpai, and S.K. Banerji

Cellular Responses of Insect Cells Spodopiera frugiperda -9 to Hydrodynamic Stresses; P.L.-H. Yeh and RK. Bajpa1

A Mathematical Model for Ripening of Cheddar Cheese; J. Kim, M. Starzak, G.W. Preckshoi, and R.K. Bajpai