Reaction Engineering

181 Pages·1982·3.402 MB·English

by  Adrian Schumpe, Gerd Quicker, Wolf-Dieter Deckwer (auth.)

24
Advances in Biochemical Engineering
Managing Editor: A. Fiechter
Reaction gnireenignE
With Contributions by
H. Binder, .K Buchholz, .W D. Deckwer,
H. Hustedt, .K H. Kroner, M.-R. Kula,
G. Quicker, A. Schumpe, U. Wiesmann
With 99 Figures and 44 Tables
galreV-regnirpS
Berlin Heidelberg NewYork 2891
ISBN Springer-Verlag 3-540-11699-0 Berlin Heidelberg New York
ISBN 0-387-11699-0 Springer-Verlag New York Heidelberg Berlin
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gniganaM Editor
Dr. Professor A. Fiechter
Hochschule, Technische Eidgen6ssische
,grebreggn6H Ziirich CH-8093
Editorial Board
Prof. Dr. S. Aiba Department of Fermentation Technology, Faculty of
Engineering ~ Osaka University, Yamada-Kami, Suita-
Shi, Osaka 565,'Japan
Prof. Dr. B. Atkinson University of Manchester, Dept. Chemical Engineering,
Manchester/England
Prof. Dr. E. Bylinkina Head of Technology Dept., National Institute of
Antibiotika. 3a Nagatinska Str., Moscow M-105/USSR
Prof. Ch. L. Cooney Massachusetts Institute of Technology, Department of
Chemical Engineering, Cambridge, Massachusetts 02139/
USA
Prof. Dr. H. Dellweg Techn. Berlin, Uulversit.~it Lehrstfuuhrl
Biotechnologie, SeestraBe ,31 D-1000 Berlin 65
Prof. Dr. A. L. Demain Massachusetts Institute of Technology, Dept. of
Nutrition & Food Sc., Room 56-125,
Cambridge, Mass. 02139/USA
Prof. S. Fukui Dept. of Industrial Chemistry, Faculty of
Engineering, Sakyo-Ku, Kyoto 606, Japan
Prof. Dr. K. Kieslich WissenschafDtilr.e ktor, Ges. ffir Biotechnolog.
Forschung mbH, Mascheroder Weg ,1
D-3300 Braunschweig
Prof. Dr. R. M. Lafferty Techn. Hochschule G-raz, Institut fiir
Biochem. Technol., Sehl6gelgasse 9, A-8010 Graz
Prof. Dr. K. Mosbach Biochemical Div. ChemicaCle nter University of Ltmd,
S-22007 Lund/Sweden
Prof. Dr. .11 ."2 Rehm Wesff. Wilhehns Universitfit, Institut f'tir
Mikrobiologie, TibusstraBe 7--15, D-4400 Miinster
Prof. Dr. P. L. Rogers School of Biological Technology, The University
of New South Wales. PO Box ,1
Kensington, New South Wales, Australia 2033
Prof. Dr. H. Sahm Institut f~r Biotechnologie, Kernforschtmgsaulage
Jiilich, D-5170 Jiilieh
Prof. Dr. ~K Schiigerl Institut fiir Technische Chemic, Universit/it Hannover,
CaUinstraBe 3, D-3000 Hannover
Prof. Dr. H. Suomalainen Director, The Finnish State Alcohol Monopoly, Alko,
P.O.B. 350, 00101 Helsinki 10/Finland
Prof. Dr. S. Suzuki Tokyo Institute of Technology, Nagatsuta Campus,
Research Laboratory of Resources Utilization,
4259, Nagatsnta, Midori-ku, Yokohama 227/Japan
Prof. Dr. H. Taguchi Faculty of Engineering, Osaka University, Yamada-kami,
Suita-shi, Osaka 565/Japan
Prof. G. T. Tsao Director, Lab. of Renewable Resources Eng., A.A . Potter
Eng. Center, Purdue University, West Lafayette,
IN 47907/USA
Table of Contents
Gas Solubilities in Microbial Culture Media
A. Schumpe, G. Quicker, W.-D. Deckwer ........
Reaction Engineering Parameters for Immobilized Biocatalysts
K. Buchholz . . . . . . . . . . . . . . . . . . . . . 39
Purification of Enzymes by Liquid-Liquid Extraction
M.-R. Kula, K.'H. Kroner, H. Hustedt.. ' ........ 73
Biomass Separation from Liquids by Sedimentation
and Centrifugation
U. Wiesmann, H. Binder . . . . . . . . . . . . . . . . . 911
Author Index Volumes 1--24 . . . . . . . . . . . . . . . 371
Gas Solubilities in Microbial Culture Media
Adrian Schumpe and Gerd Quicker
Institut f'tir Technische Chemie, Universit/it Hannover, D-3000 Hannover 1, FRG
Wolf-Dieter Deckwer
Fachbereich Chemie, Universit/it Oldenburg, D-2900 Oldenburg, FRG
1 Introduction .................................................................... 2
2 Methods for Expressing Gas Solubility ............................................. 3
3 Experimental Techniques ......................................................... 5
1.3 General Methods ............................................................ 5
3.2 Methods Applied to Microbial Culture Media ................................... 5
4 Theories of Gas Solubility ........................................................ 8
5 Parameters Affecting Gas Solubilities in Microbial Culture Media ...................... 01
1.5 Pressure .................................................................... 01
5.2 Temperature ................................................................. 01
3.5 Composition ................................................................ 21
5.3.1 Single and Mixed Electrolytes ............................................ 31
5.3.2 Organic Compounds .. : ................................................. 81
5.3.3. Adsorption Effects ..................................................... 22
6 Predictions of Solubilitiesi n Media ................................................ 24
7 Estimation of Solubilities during Actual Bioreactions ................................. 82
1.7 Direct Predictive Method ..................................................... 82
7.2 Indirect Predictive Method .................................................... 3t
7.3 Failure of Predictive Methods ................................................. 33
8 Concluding Remarks ............................................................. 34
9 Acknowledgements .............................................................. 53
01 Nomenclature ................................................................... 53
11 References ...................................................................... 36
Available information on gas solubility in microbial culture media is reviewed. Emphasis is given
to oxygen and carbon dioxide solubilities. Experimentatle chniques which can be successfully applied
to culture media are presented. All the parameters which affect gas solubilities, i.e., above all the
composition of the media are thoroughly discussed. In general, gas solubilities in nutrition and
cultivation media can be predicted by a log-additivity approach. To this end knowledge of the
composition of the media and the solubility parameters (KI) of the individual compounds is required.
For a variety of substances encountered in cultivation broths the parameters ~K for oxygen could be
evaluated from literature data and are summarized in this paper. Appropriate recommendations for
applying direct and indirect predictive methods are given. Cases of failure are mentioned as well.
2 A. Schumpe, G. Quicker and W.-D. Deckwer
I Introduction
The solubilities of gases in liquids are fundamental physicochemical data. They are
often referred to as physical or saturation solubilities. In biosciences as, for instance, in
fermentation technology, algae cultivation, marine technology, waste watetrr eatment,
physiology, and environmental sciences, it is the knowledge of the solubilities of
oxygen and, to a lesser extent, of carbon dioxide which is particularly needed. In
general, gas solubilities are required
(i) to establish mass balances,
(ii) to calculate yield coefficients (stoichiometry),
(iii) to determine volumetric mass transfer coefficients,
(iv) to design and scale up bioreactors.
Solubilities are essentially responsible for the value of the driving concentration
difference of mass transfer between the gas and the liquid phase. It can be
assumed that exact knowledge of 0 2 and CO 2 solubilities in biological culture
media may contribute to obtaining a deeper insight into and better interpretation of
various bioprocesses.
In biotechnology, it is especially the 0 2 solubility which is of major importance.
0 2 determinations in microbial culture media are conveniently carried out with the
help of the polarographic probe .>2,1 Such probes give a current which is proportional
to the diffusional flux of oxygen across the probe membrane. The diffusional flux,
in turn, depends on the chemical potential of oxygen and hence on its fugacity which,
for the sake of simplicity, is often called oxygen partial pressure. It is important
to note that in aqueous solutions of various composition the oxygen fugacities are
equal if these solutions are in equilibrium with the same gaseous phase. However,
the actual amount of 0 2 present in the solutions may be quite different, of
course. This is shown schematically in Fig. t. The addition of electrolytes and
alcohols changetsh e 0 2 solubility while the fugacity and partial pressure, respectively,
remain constant. The partial pressure, p, and the solubility, c, are interrelated by
Henry's law:
p = H.c m (1)
where H, is Henry's constant.
P
Fig. .1 Principal dependency of partial pressure and
dissolved gas concentration on the concentration of
added compounds
= C add
Gas Solubilities in Microbial Culture Media 3
Numerous experimental data on gas solubilities, particularly for , 2 0 are available
from the literature. However, most data refer to simple systems like solutions of
single salts or organic compounds. In contrast, microbial culture media are complex
since a number of organic compounds, salt mixtures and metabolites are usually
present. The addition of salts and sugars usually decreases the gas solubility while
the latter may increase if short-chain alcohols are present. The effect of metabolites
on the 0 2 solubility seems to be complex but only insuffident data is available.
This paper summarizes knowledge published on gas solubilities in microbial
culture media. Emphasis is placed on the solubilities of oxygen and carbon
dioxide. Experimental techniques for measuring gas solubilities are outlined and the
shortcomings of some theoretical approaches are mentioned. A review is given on
the influence of various substances on gas solubility. It naC be assumed that many
substances dissolved in water and possibly present in biological media act inde-
pendently. It will be shown that under this condition their effects on gas solubility
can often be accounted for by an additive approach. This makes it possible to
reliablye stimate 0 2 solubilities in nutrition media and fermentation broths provided
their composition and the individual solubility parameters of the substances present
are known with sufficient accuracy. Such solubility parameters evaluated from
previous measurements and from literature data are given in this paper and their
application is demonstrated. Also other direct and indirect methods for solubility
estimations in microbial culture media are discussed.
2 Methods for Expressing Gas Solubility
There are various ways of expressing gas solubility .)3 The equilibrium liquid phase
concentration is often given, e.g., as
c mass concentration (mg 1-1)
m c molarity (mole - 1 )1
w mass fraction (--)
x mole fraction (--)
stating both the temperature and the pressure the data refer to. If Henry's law
holds it may be more convenient to calculate Henry's constants using any of the
various concentration measures:
H Henry's constant, e.g.,
m H = P (kPa I mole- )1 (2)
m C
x H = P (kPa) (3)
X
HL = s~-'C (--)" (4)
C
4 .A and G. Deckwer W.-D. Quicker Schumpe,
The reciprocal of H ,L i.e. the ratio of the liquid to the gas phase concentration, fbr
low solubilities is equivalent to the Ostwald coefficient:
L Ostwald coefficient (--)
(= ratio of the volume of gas absorbed per unit volume of the solvent).
More often the solubility data are corrected for a standard pressure the correction
usually assuming ideal gas behavior and validity of Henry's law resulting in one of
the following coefficients:
Bunsen coefficient (--)
(= volume of gas reduced to 0 °C and t01.3 kPa 1( atm) absorbed by unit
volume of solvent at a gas partial pressure of 101.3 kPa),
3[ absorption coefficient (--)
(= volume of gas, reduced to 0 °C and 101.3 kPa 1( atm) absorbed by unit volume
of solvent at a total pressure of 101.3 kPa including the solvent vapor
pressure).
S Kuenen coefficient (cm 3 g-l)
(= volume of gas (in cm )3 reduced to 0 °C and 101.3 kPa 1( atm) dissolved
in the quantity of solution containing g 1 of solvent, i.e., S is proportional to the
gas molality)
w C weight solubility (mole g-L)
(= moles of gas dissolved per gram of solvent 'at a gas partial pressure of
101.3 kPa 1( atm)).
For convenience, the conversions of the different coefficients into the Bunsen
coefficient, ~, which will be used in this paper are listed below. (For symbols and
units see nomenclature)
273.15 L
- (5)
T
101.3
- [3 (6)
101.3 -- Ps
= 1(sQ -- w) S (7)
= Qs,VoCw • (8)
In case of low solubilities the following relationships are as well approximately
valid:
101.3Vo 101.3Vo
= ~ c - - - mC (9)
106pMG 103p
oV~Q oV~Q
= -- w = x )01(
Me; t~M
o 101.3 V oV~Qp
~o = 10 3 Hml = ~---~M H;l (11)
273.15
t0 Hr. ~ (t2)
T
Gas seitilibuloS ni Media Culture Microbial 5
3 latnemirepxE seuqinhceT
3.1 General Methods
Gas solubilities have been measured quantitatively for almost two centuries now
and many techniques and apparatuses have been developed for this purpose. There
are two groups of methods: chemical methods to analyse gas saturated solutions
and physical methods which mainly determine either the amount of gas necessary for
saturating the initially gas-free solvent (saturation methods) or the gas which can be
desorbed from the saturated solution (desorption methods).
Chemical determinations are essentially gas specific. The most important one of the
chemical techniques is Winkler's method for dissolved oxygen analysis. The basic
chemical steps involved are the oxidation of manganous hydroxide by the dissolved
oxygen in an alkaline solution, reduction of the produced manganic hydroxide by
iodide upon acidification and titration of the liberated iodine with a thiosulfate solu-
tion. Some of the most precise determinations of the oxygen solubility in water have
been carried out by refinements of the fundamental procedure. However, other solutes,
e.g., buffering, oxidizing or reducing substances may interfere with certain steps. In
some cases, this can be overcome by special modifications ~4 but generally only at the
cost of both convenience and accuracy.
There are also some physical methods to investigate the dissolved gases directly
(e.g., photometric methods) but more often the gas is removed from the solution to
avoid possible interferences with other solutes. The desorption may be accomplished
by applying a vacuum as, e.g., with the classical van Slyke apparatus. Preferably the
gas is stripped from the solution by an inert gas purified and either reabsorbed in
pure water for analysis or analysed in the gas phase, e.g., by means of a gas
chromatograph or a mass spectrometer. In this way the amount of different dissolved
gases can be investigated simultaneously.
The saturation methods also require a preceding desorption process in order to
free the liquid from dissolved gases. This is usually accomplished by boiling the liquid
under vacuum. Other techniques used less frequently are spraying the liquid through
a fine nozzle into an evacuated chamber or evacuating the frozen solution. The
latter method reduced the solvent losses involved. Solvent evaporation may be
critical especially in the case of mixed solvents since different volatilities of the
components result in a change in composition. The gas-free solvent is then brought
into contact with the gas. The amount of gas absorbed in the equilibration process
may be investigated by observing either the isobar volume reduction or the isochor
pressure decrease.
Detailed descriptions and the particular references can be found in the reviews of
Markham and Kobe ,~5 Battino and Clever 3), Clever and Battino >6 and the textbook
of Hitchman .)1 Hereo nly a few methods which have so far been applied to microbial
culture media will be discussed in more detail.
3.2 Methods Applied to Microbial Culture Media
Gas solubility measurements in microbial culture media have almost exclusively
been devoted to the solubility of oxygen. Winkler's method was found to be ill-suited