This is the seventh in a series of symposia devoted to talks by students on their biochemical engineering research. The first four meetings were held alternately at Kansas State University and the University of Nebraska–Lincoln, with participants from those two schools. The next two took place at Kansas State and then in conjunction with the 8lst American Institute of Chemical Engineers National Meeting in Kansas City, with attendees from Kansas State and Iowa State Universities. This meeting, at Iowa State, was the first to include participation from the University of Missouri–Columbia.

Contents
"Properties of Soluble and In:anoblized Dextransucrase," Hossein Kaboli and Yah Eric Chen, Iowa State University

"Growth of Lipid-Producing Organisms on Formic and Acetic Acid-Containing Waste Waters," Lin-Chang Chiang, University of Missouri–Columbia

"Design of an Automated Alkaline Copper Reducing Sugar Assay," Alfred R. Fratzke and James R. Frederick, Iowa State University

"Determination of Oxygen Transfer Coefficients in Hydrocarbon Fermentations Using a Material Balance Method," Sarafin N. Sanchez and J. R. Gutierrez, Kansas State University

"Oxygen Transfer Characteristics in One Stage and Two Stage Air-Lift Towers," Mark E. Orazem, Kansas State University

"A Comparison of Biological Digestibility Tests for Cellulose," Dou-Houng Hwang, University of Missouri–Columbia

"Mechanism of Enzymatic Hydrolysis of Cellulose," L. T. Fan, Yong-Hyun Lee, and Liang-Shih Fan, Kansas State University

"Purification of Xylan-Hydrolyzing Enzymes," James R. Frederick, Alfred R. Fratzke, and Mary M. Frederick, Iowa State University

"Cellulase Production from Bagasse and Pith," A. Ferrer, Y. Alroy, and I. Brito, Kansas State University

This booklet contains abstracts of papers presented at a biochemical engineering symposium conducted at the University of Nebraska-Lincoln on April 29, 1972. This was the second annual symposium on this subject, the first having been held at Kansas State University on June 4, 1971. It is expected that future symposia will alternate between the two campuses.

Contents
S.H. Lin, Kansas State University, "Enzyme Reaction in a Tubular Reactor with Laminar Flow"

Gregory C. Martin, University of Nebraska, "Estimation of Parameters in Population Models for Schizosaccharomyces pombe from Chemostat Data"

Jaiprakash S. Shastry and Prakash N. Mishra, Kansas State University, "Immobilized Enzymes: Analysis of Ultrafiltration Reactors"

Mark D. Young, University of Nebraska, "Modelling Unsteady-State Two-Species Data Using Ramkrishna's Staling Model"

G.C.Y. Chu, Kansas State University, "Optimization of Step Aeration Waste Treatment Systems Using EVOP"

Shinji Goto, University of Nebraska, "Growth of the Blue-Green Alga Microcytis aeruginosa under Defined Conditions"

Prakash N. Mishra and Thomas M.C. Kuo, Kansas State University, "Digital Computer Simulation of the Activated Sludge System: Effect of Primary Clarifier on System Performance"

Mark D. Young, University of Nebraska, "Aerobic Fermentation of Paunch Liquor"

This symposium is the sixth of an annual series conducted so that results of biochemical engineering research can be exchanged by the researchers who actually carry it out. The first four meetings were held alternately at Kansas State University and the University of Nebraska–Lincoln for attendees from those two schools. The fifth and sixth involved participants from Kansas State University and Iowa State University; this was the first meeting away from a university campus.

Contents
"Mathematical Model of Oxygen Transfer in Airlift Fermentors," Chester S. Ho, Kansas State University

"Effect of Column Height on Oxygen Transfer in Airlift Systems," Mark E. Orazem, Kansas State University

"Mixing Studies in an Oil-Water Airlift System with Motionless 15 Mixers", J. R. Gutierrez, Kansas State University

"Purification and Properties of (3-Xylosidase," Gbekeloluwa B. Oguntimein, Iowa State University

"Immobilization of Invertase to Cellulose with Cyanuric Chloride," William J. Smith, Iowa State University

"Purification and Properties of Dextransucrase," Yah Eric Chen and Hossein Kaboli, Iowa State University

"Properties of Immobilized (3-Amylase," Clarence C. Ron, Iowa State University

The symposium whose papers are abstracted here was the fourth in a series held alternately at Kansas State University and the University of Nebraska–Lincoln. Requests for further information on projects conducted at Kansas State should be directed to Professor L.E. Erickson and on those at Nebraska to the editor.

Contents
John C. Heydweiller, "Estimating Sedimentation of Organisms in a Tower-Type Activated Sludge System"

Raymond C. Eliason, "Properties and Utilization of Small Particulates in Cattle Manure"

Kenneth H. Hsu, "Oxygen Transfer in Tower Systems with Motionless Mixers"

Raymond C. Eliason, "Hydrolysis of Sucrose by 20 Invertase Immobilized on Hollow Fibers"

Robert Shipman, "Single Cell Protein from Photosynthetic 26 Bacteria"

Peter J. Reilly, "Stability of Commensalistic Systems"