ENGINEERING SCIENCE
Comparison of Bacterial Growth in Single and Mixed
Populations of Sewage Origin
R. B. BUSTAMANTE and A. F. GAUDY, JR.
Bioenctneerinl' Laboratories, School of Civil Endneerin&'
Oklahoma State University, Stillwater
IN'1'BODUcrION
Of all the microscopic forms of life directly or indirectly involved in
the removal of organic matter from waste waters, bacteria are recognized
as the most important. No one specific genus or strain of bacteria is
responsible for waste water pUrification. Usually, large numbers of different strains of bacteria are expected to be present in biological sludges.
No ~ttempt is made to control which types of organisms are present in
wast\! treatment reactors, and the "how" and "when" of bacterial predomi; lance changes are largely unknown.
1'1 dealing with heterogeneous populations, massive changes in bacterial predominance are fairly common and have been observed in chemostats operated in the Bioengineering research laboratories at Oklahoma
State University. It was felt that if a better understanding of the mechanisms of bacterial interaction were obtained, this knowledge would be
helpfUl in predicting possible predominance changes in reactors such as
activated sludge aeration tanks, and might result in improved design procedures and provide insights into more close control of treatment plant
efficiency.
The work reported here represents a portion of long-term studies
being conducted by us and pertaining to factors whIch affect changes in
bacterial predominance. The results presented herein include a study of
the biochemical response and growth kinetics of selected pure cultures
and of mixtures of pure cultures.
LITERATURE REVIEW
One of the first investigators to observe and report changes in bacterial predominance was DeBarry (Waksman, 1937). He observed that
if two organisms were grown together one would eventually predominate
over the other. Various investigators have also reported on benefic:al
effects of mixed populations in fermentations. Sherman and Shaw (1921)
reported that fermentation of lactose to propionic acid would take place
faster by the combination of Streptococcus lacttc1Ul or Lactobacillus ca.sei
with Bacterium acidipropionici than by the single species acting alone.
Sanborn (1926) observed that the decomposition of cellulose by
CellulomotaaB folia was aided by the presence ot other organisms which
would provide essential components.
Savastano and Fawcett (1929) observed the selective effect of temperature on mixed cultures. Fawcett (1931) observed that Investigators
using pure cultures in plant pathology research were not obtaining saUsfactory results; he recommended that the effects ot known mixtures ot
microorganisms and their relation to plant diseases be more actively investigated.
Waksman (1937) listed the following factors as determfnlng the extent of the development ot anyone group of organfama in natural sub-
strates:
1)
food supply, inorganic materlal8
"2
PROC. OF THE OKLA. ACAD. OF SCL FOR 1966
2)
environmental conditions, such as temperature and oxygen sup-
ply
8)
the presence ot other orge.ni8ms producing toxic or stimulating
8Ub8tance.
4)
the presence of predators.
In the waate treatment field, activated sludges have been studied and
found to be composed of microorganisms inclUding bacteria., molds and
protozoa, and metazoa such as rotiters, insect lanae and worms (Rich,
1968). Wattle (1942) classified all floc-forming organisms as members
ot the species Zooglea Tamigera. However, Winogradsky (1930) had previously found that the predominant organism in activated slUdge was of
the genus NttTocyatia. Jasewicz and Porges (1956) observed in batch
studies that 74% of the bacteria in the assimllative phase were either
BtICillua or Bacterium, while these genera comprised only 8% of the
organisms present in the endogenous phase. Rao and GaUdy ( 1966), in
long-term studies with heterogeneous populations, found that the relationship between initial solids concentration and COD removal rate varied
for a single SUbstrate, as did the cell yield. These variations were correlated to observed changes in predominance in the experimental units
during the period of the study. Jeris and McCarty (1965) suggested that
anaerobic digester failures may occur due to a change in predominance of
acid-forming bacteria resulting in the accumulation of different substrates
for which the appropriate species of methane bacteria are not present.
It can be seen from this brief review that changes in species predominance in waste water treatment processes are of significant interest to
the biological waste treatment field.
MATmIALS AND METHODS
Bynthetto !CaBte-The constituents of the synthetic waste used in this
study are given in Table L
TABLE
Constituent
I.
COMPOSITION OF SYNTHETIC WASTE
Concentration
mg/l
Glucose
100 - 1000
(NH.),SO.
500
KgSO..7H.O
100
MnSO..H.O
FeC1e-e BaO
CaCla
KBaPO.
K.HPO.
10
0.5
7.5
526
1070
. ~ t uecl .. OOt."'9 growt1, etm.'63-The shaker flasks used
for powth curve experiments were of a special design and were fitted to
tubee which permitted Ught transmittance readings at 540 m" by inverting
and plac1Dg the tubes in a spectrophotometer (Bausch Ie Lomb Spectronic
20). The f1aaks were shaken at a constant speed of 90 strokes/min in a
water bath llhaker apparatus operated at a temperature of 25 C.
ENGINEERING SCIENCE
Viable cell covnta-Viable bacterial counts were obtained by the
spread-plate surface-counting technique.
Analyttcal Technique.s-Glucose was measured using the Glucostat
technique. Biological solids concentrations were determined by the membrane-tilter technique (0.45 p). Oxygen uptake was determined using a
Warburg respirometer operated at a shaker rate of 110 oscillations/min
and constant temperature of 25 C. This oscillation rate in the Warburg
was found to give comparable kinetics to the shaker speed ot 90
strokes/min on the constant temperature shaker apparatus used for the
determination ot growth curves.
Bacterial cultures-The pure cultures of bacteria used in these studies
were either isolated trom sewage or known to be present in the sewage.
These organisms were selected tor study because their growth characteristics when plated on an agar surface were such as to allow rapid and
accurate identification. The organisms used were as tollows:
P8eudomonas ae1'UgitlO8tJ
Serratia
marC68CBn8
BscherichitJ coli, K-12
An unidentified organism, hereafter called Yellow organiBm
An unidentified organism, hereafter called Blue organiBm.
Experimental protocol-Investigations were conducted in three phases:
1)
growth studies using pure cultures
2)
biochemical behavior ot pure cultures
3)
studies using mixed pure cultures.
Specific aspects of experimental protocol are presented below.
RESULTS
pure cultures-A series ot growth flasks containing five different glucose concentrations were set up in duplicate tor
1.
Growthstudie8
01
each of the pure cultures studied. Light transmittance readings were
made throughout the course ot growth, and the readings were converted
to optical densities and plotted. Growth curves for an experiment using
Paeudom0ntJ8 aeruginoBa are shown in Figure 1, and in Figure 2 the same
data are plotted on semi-logarithmic paper. The straight-Une sections of
the curves were used to determine the logarithmic growth rate. Growthrate values are plotted vs. substrate concentration in Figure 8.
Some time ago, Monad (1949) observed that the value ot the logarithmic growth rate, p., is not constant, but depends upon the concentration
ot the limiting growth metaboUte. Based on his experimental resulta, be
developed the following equation:
p
= "-.as 8/(k. + 8)
where:
"-.as = maximum growth rate
8
= concentration of
=
11m1t1ng metaboUte
k.
saturation constant, numerically equal to the substrate concentration &t which the growth rate Is p_.I2. Values of IIau and k. can
be obtained sa abown in Figure 3.
444
PROC. OF THE OKLA. ACAD. OF seL FOR 1966
1.0
0.8
.
»
....
~ 0.6
ell
~
~
....u•
..
8 0 •4
0.2
o
o
2
4
6
Ti_ (bours)
9
~o
12
Figure 1. Growth of Pa6tulomonM aerugino8a on various concentrations
of gluc08e
In a 8imilar manner, Figures 4, 5, and 6 show growth curves and a
plot of p VS. S for the Yellow organism. This organism is particularly
intere8lli1g because of the sensitivity of its growth rate to changes in
substrate concentration. Values of PlJlut kIf and cell yield for the fIve
organisms studied are shown in Table II.
2. Blochemkal be1&avror 01 pure cuZtures-In these experiments COD
removal, oxygen uptake, glucose removal, and biological solids concentration were used as parameters to assess the biochemical beh3.vior of
the cultures during growth. Figures 7 through 11 sh:>w the biochemIcal
behavior of the pure cultures under study. From these figures it can be
seen that the BZue organism, ~8eudomonM aerugin08a, and Serratia
mGrce..9C6M produced considerable amounts of metabolic intermediates
and/or end products during the substrate removal pariod. This may be
dlBcemed by comparing the COD removal curve and the glucos3 COD
utUlzation curve. B8Cherichja col' K-12 also produce:1 intermediates, although at a slower rate than the three previously mentioned organisms.
It la seen in Figure 10 that a very limited amount of material was excreted
into the medium during metabolism by Yellow orga,,18m.
S. 8tt1d'e8 ""'"g mbtuT68 01 pure ewture8--Thase studies were performed by setUng up three different systems at the Eame substrate concentration; two for each pure culture, and one for the mixed system.
COD. glucose. and solids concentration for the two single organism systema were not determined, since the biochemical behavior of tha pure
culture8 already had been shown (Figures 7 through U).
&w:AericAtG
K-12 and the YeUoto orgatabm were found to have
reJatlve1y low /I-.. values, and it was desirable to determine the behavior
eo"
ENGINEERING SCIENCE
1.0
0.8
0.6
~
0.4
0.2
0.1
0.8
~
/
t' 0.6
--
of'i
0.4
"0
.-l
cu
.~ 0.2
....
0-
o
0.1
0.8
0.6
~
---
~~--
v
---=1 .-
---------- --- -------- --.
~
o
>--
--------- f - - -
--
-- ~--
..,
-- ~-
l~
700 mg!
500 mg!l
~
I
--'------ - -- -----
0.2
lOOO IngA
-- ~----
--- --------------
0.4
0.1
~
--.------ V
rJl
~
/
~
/
V
..,
300 mg!l
---_.- ,......--.-
r'.- - -.
100 mg!l
..,
~
I
2
4
6
10
8
Time (hours)
Figure 2.
Effects of glucose concentration on growth rate of Pseudomona.s
aeruginosG
TABLE II.
KINETIC CONSTANTS AND CELL YIELD FOR SELECTED ORGANISMS
OrganjSIn
Cell Yield
mg Sollds!mg Glucose
p....."
k.
Blue organism
0.375
22
0.697
Paffidom<maa aernginosa
0.340
40
0.482
8eTTatia marCe8cens
0.290
M
0.447
Yellow orgClniam
0.220
230
0.478
B8Cherichia coli K·12
0.170
20
0.424
·46
PROC. OF THE OKLA. ACAD. OF SCI. FOR 1966
0.400
Pmax
-----~
QI
~
./'
~ 0.300
-
-~
V-
0.340
- -
~
~
".
til
-;; 0.200
c
QI
c
-/
&.
A 0.100
-----_._- r'-'
I
I
_
IIi
I k8
~
I
o
-
-
I
---
....
~
0
_ ..
(
s:
-0
._----
I
- - - - _...._.1 ___.- _
~-
--- - --
40
!
I
I
o
200
400
600
800
1000
Glucose concentration (mg/l)
Figure 3.
1.0
----_.- _._-
0.8
.
i
Determination of maximum growth rate (pm.. ) and saturation
constant (k.) for Pseudomona8 aeTtl,gin08a
_
_.... -------+----+--
t-I
>.
•
- -_. - ------
. _ - ' - - - ---
- - -- - - -~'_~,L...--__ii__
0.6
'0
004
..
8'0.4
II
U
...
300 11I&.1
0.2 ~----l100 ag/1
o
o
2
4
6
8
10
12
14
Ti_ {hour.)
JI'lgure 4.
Growth of Yellow orgatdsm on various concentrations of glu:'
coee
447
ENGINEERING SCIENCE
1.0
0.8
0.6
0.4
0.2
-~
~
~
~
V
1000 1IC/1
~
V
0.1
0.8
100 WII/1
t' 0.6
~
~ 0.4
41
~
....
~ 0.2
---d
.
'"+0
8
-
~
~
~
-
~~
r:::::--
500 . ./1
0.1
0.8
0.6
30~ . ./1
0.4
__0""'---- ~--
0.2
~
-rr---'
~
1
-
)~
100 11&/1
0.1
o
2
Figure 5.
..
6
8
Tl. (hour.)
10
12,
Effects of glucose concentration on growth rate of yellow organism
I
--------- -- - -fAux - 0.220
0.200
1- -
k
~
~ o.lSO
ok
I~
0 :~_
!
I
iii
.
~
~ 0.100
1=
8Ii
0.050
~-
/~
.••
...
---...____t-- - - --
- ----
---- - - --
/
ba.
0
Ii
1
l
I
I
,
I
I
I
I
:
I
i
I
I
'--f--
I
I
[7
I
I k.
- 230
!
200
400
fOG
SUbstrate c:oaceutrau.oll
1000
<../1)
Figure 6. Determination of maximum growth rate ("... ) and saturation
constant (k,) tor Yenow organism
"'
PROC. OF THE OKLA. ACAD. OF SCI. FOR 1968
of tbeae organl8m8 when grown in combination. FIgure 12 shows the
biochemical reapolUle of the mixed system. A small amount of metaboUc
lntermecUatee or end producta was produced in this experiment, and it is
Hen that a sUghtly higher yield was obtained tor the mixed system than
for the pure cultUI'H alone. For a period of 7% hr the oxygen uptake ot
the m1xed syltem was very close to the sum of the oxygen uptake of the
pure culture syltems. Indeed, the uptake of the mixed system was slightly higher than the sum' of the pure cultures (Table m). In Figure 13 the
viable growth curves ot the mixed cultures are shown. The growth pat-
tel'll8 in the mixture were 8im1lar to those for each organism alone, and
the ftnal viable counts were very close. Additional experiments performed wIth the same organJams confirmed these results. From the data preHnted in the figures it may be concluded that there was no antagonistic
relationship between these organisms; there was, on the other hand, a
IUght increase in the system activity resulting from combined growth.
The biochemical response of a mixed system consisting of a fastgrowing organism, Serratja marceacetl3, and a slow grower, the Yellow
orgGtHam, is shown In Figure 14. The mixed-culture yield was slightly
higher than that tor the pure cultures. The oxygen-uptake curve of the
mixed system closely resembles that ot Serratia marcescens alone, and
during the inltial stages ot the experiment the oxygen uptake of the
mixed system was very close to the summation of oxygen uptakes for the
individual organisms (see Table IV). Viable-count data during these
experiments are shown in Figure 15. It is clearly seen that in the mixed
system SeN'CJ,tia marCe3Cen8 predominated over the Slow-growing organlam. It seeml apparent th'8.t the response is dependent upon the relative
growth rates.
600r-----r---_--.,~--~---~---....,..---~--_
Solids
. _- -----f--
400
~
'300
r
200
Oxygen Uptake
I
I
100
OOD
o
2
Flpre 7.
4
6
Tl.e (hours)
8
10
12
Substrate removal and growth, BII46 orgaaUm
m.
10~
6%
8JM
8%
7%
8%
8%
."
.~
Ohr
1%
2JM
2%
8%
Time
TABLE
Uptake. mg/l
Viable Count, cell8/mI
6.45XIO'
2.75X10'
1.58X10'
7·90X10'
8.I5OXI0'
7·80XI0'
Viable Count
Eo coli 1t-1I
~
98
7~
68
8G
..
18
22
8
OJ
Uptake
---
1"0
87
11$
62
~8
1·O'X10'
8.85X1()1
~.15XIO'
288
145
187
81
106
~8
28
12
27
1.75X 1()1
2.SSXl()1
2.2SXl()1
Sum
0,
Uptake
1~
8
Viable Count
Yellow organism
Uptake
Oz
218
192
158
87
115
29
51
13
0,
Uptake
5.80X 10'
2.60X 10'
1·80X10'
9·50XIO'
1.05X 1()1
5.00X 10'
9·90X10'
7.7O XlO'
8·05Xl()I
6.80X10'
2.35XIO'
2.39Xl()1
Mixed Sy.tem
Viaole Count
Yellowora&ni.m
E. coli
OXYGEN UPTAKE AND VIABLE COUNT FOR E. coli AND Yellow organmn. IN PuBE CULTURES AND IN MIDJ)
CULTURES
i
i
Q
I
g
81h
1:y,.
2
2%
8%
4:y,.
5
7
Ohr
Time
TABLE IV.
1.07X 10'
8.15X10'
1.17X10'
5.75X10'
2.10X1()1
Oxygen Uptake, mg/l
Viable Count, cells/ml
190
94
127
68
28
2·40X 101
Serratia mareaeena
01
Uptab
Viable Count
CULTUBE8
144
17
29
45
8
2.35X10'
8.35X10'
9.95X10'
1·50X1()1
1.73X10'
1.09X 10'
Viable Count
YeUow orpniam
Uptake
(h
334
123
172
80
36
Sum
01
Uptake
203
76
107
145
38
0,
Uptake
7.75X10'
1.02X10'
1.02 X 10'
6.55X 10'
1.55X10'
1.85X10'
S. marc_cena
4.80 X 10'
1.00X 10'
6.00X10'
"'-00X 10'
1.35X10'
9·50X10'
Yellow oraanUm
Mbed S7atem
"ILHe CoIlD'
OXYGEN UPTAKE AND VIABLE CoUNT FOR Ben"atia maTceaceu AND YellotD orgafliam IN PUD CULTUUS AND
IN :MIXED
co
~
I-'
~
~
rn
~
o
g
~>
~
IzJ
~
o
i
ENGINEERING SCIENCE
451
600
500
400
~ 300
I
200
100
2
4
6
Time (hours)
Figure 8.
8
10
Substrate removal and growth,Pseuaomona8 aerttginosa
Experiments were also conducted using a fast-growing organism
(BeJT'GtfG marceacena) in combination with Bscherichia coli K-12, which
exhibited the lowest 110-- value of the five microorganisms studied. A
amall inoculum of S61'7'afia marceacena and a fairly large inoculum of
Bac1wnicAia co" were incubated together. Figure 16 shows that Sen-atia
tl\Clt'CeaceM rapidly outgrew Bacherichia colt
This experiment demonstrates how rapidly changes in predominating species can be brought
about. It ia also interesting that a marked change in the color of the
mixed liquor. i.e., from whitish to red, took place during the experiment.
In this case. using pure cultures as in the work of Rao and Gaudy (1966)
U8iDg heterogeneous populations. the change in the color of the aerating
mixed liquor provided definite indication of change in predominance.
Two fast-growing organisms, Pseudomonas aervg,n08a and Blue orgotrilm, were combined for experimentation. The biochemical behavior
of the system ia shown in Figure 11. A.B expected, substrate removal
was extremely rapid. The oxygen uptake of the mixed system is very
clOlle to the sum of the uptakes of the pure-culture systems (see Table
V). The viable-count data for this experiment are shown in Figure 18.
n may be 8UI'Dl18ed from this experiment that these -organisms participated in direct competition for substrate without any apparent antagonistic ef:fect&
1%
7%
e
8%
'%
5%
8
1%
11ia
2%
Ohr
Tiaut
TAJILE V.
1.85X10'
1.20X10'
5.05X10'
2liOX10'
1.62X 10'
OXygen Uptake, mg/l
Viable Count, cella/ml
166
128
10
88
11
~·05X10'
Viable Count
Blue or....la_
MIXED CULTUBES
01
Uptake
IN
212
127
52
28
10
1.14X10'
1.23X10'
2.65X101
4.55X 10'
1.31X 10'
1liOX1O'
PlleudomolUt. aeruciuo_
0,
Uptake
Viable CoQJlt
317
155
122
81
21
216
195
113
81
23
1.00X10'
5·80X10'
5.25X10'
3·80X10'
1.35X 10'
1.09X 10'
8.2OX10'
1.85X1()1
UOX10'
1.50X1.
1·60X10'
Viable CoQJlt
Pa. aerqbaoaa
Blue oraWa-
6.85X10'
Kixed S7atem
0,
Uptake
.um
SUID
01
Uptake
OXYGEN UPI'AKE AND VIABLE CoUNT FOB Blue OTgGtIUm AND PBet&domotaaa ~ IN PuBS CUL'I'UBBS
i
~...
~
o'1j
g
>
~
o
~
~
~
s
ENGINEERING SCIENCE
DISCUSSION AND CONCLUSIONS
The data obtained from the growth experiments with pure cultures
were used in the detenntnation of the kinetic growth-constants of each culture by the graphical method shown in Figures S and 8. Using p.u as
the principal growth parameter, the results of mixed culture experiments
show that it 18 possible to predict the predominating organism when two
strains are placed together, assuming that there is an appreclable difference in their respective growth ~tes. Relating these observations to the
biochemical behavior of the pure cultures, it can be seen that the fastgrowing organisms metabolize glucose at a high rate, while at the same
time introducing large amounts of metabollc intermediates and/or end
products into the medium. These intermediates appear to be sequentlally
metabolized immediately after the glucose is exhausted, indicating the
presence of constitutive enzymes in the organisms which are appropriate
for the assimllation of the intermediate products. These findings suggest the possibility that these fast-growing species may affect other
species through the production of the elaborated products. However, no
evidence of antagonistic relationships was found; indeed, no antagonistic
relationships of any type were noted. The oxygen uptake data point, however, to a small but noticeable beneficial relationship in the mixed cultures.
600
r-o----r-----...,.----r-----r-----,.------,
500 1--~-~:-+------+----i-----+-----+-------1
400 I----"'""'\--+---+---+----t-----t-------t------t
Solids
~ 300 .-----k----+-t----~t'-----+-----r------1
if
200 1------H~---4'r_---i----~ Oxygen Uptake
100~==---'f--T--+__::7~~_r_---_t_---_r---.,
COD
2
FIgure 9.
4
6
8
Tl.e (hours)
Substrate removal and growth, BerratfG
m4rCeBcena
~
PROC. OF THE OKLA. ACAD. OF SCI. FOR 19M
It,
88
shown In these experiments, the most Important factor govern-
ing the predominance of one strain over another 18 stmple competition for
substrate, then it may be possible to predict predominance In more complicated systems. The present Une of Investigation Is being expanded to
include more complicated environments, e.g., more than two species, multi..
substrate media. continuous flow conditions, etc. It should be empbasized that changes in predominance in continuous-flow reactors do occur
in an, as yet, unpredictable manner; therefore the problem would appear
to be more complex than that presented by simple substr&te competition.
Furthermore, the presence of other types of organisms 8uch ~ protozoa
in activated sludge and their effects on predominance contribute to the
general complexity of predicting species predominance and changes in
specific population density. Much more work is needed on the mechanlsm8
of species predominance before attempts can be made to control plant
operations to select and maintain the moat desirable organisms. Also,
while much more experimentation is needed in order to draw sound conclusions tor less complicated systems, tentative patterns for predicting
predominance may be drawn from these simple model systems. For example, it would appear that in these studies, in which there W88 no evt600 _---....,...---~----.,..._--......- - - _ - - - _
500
400
Solids
.:::: 300
bll
S
200
Oxygen Uptake
100 t------+-------4------::lol'---1Io..----+-~,.__-__t---__f
COD
O'--_ _...;::;;L.
o
2
--L
4
...
6
-'-
8
-"1I~----'
10
T1-.e (hours)
FIgure 10.
Substrate removal and growth, YBilow orgatMMn
ENGINEERING SCIENCE
dence for antagonism and where the competitive situation involved one
of simple competition for available substrate, the organism which exhibited
the highest value of /lmn may be expected to become predominant. Considerably more work is needed in discontinuous systems to detennlne the
effect that k, may have in establishing predominance tor organisms with
approximately the same pm.... value.
675
600
500
i
400
I-------+------+------~I-----~..----
I,
300
i
200
100
COD
1--------+----+-----.-----,,...e---~_.,,;I!Z___\__+---__+_--___4
o
o
o
~igure
2
4
6
8
10
12
TilDe (hours)
11.
Substrate removal and growth, Escherichia coli, K-12
PROC. OF THE OKLA. ACAD. OF SCI. FOR 1966
800
Cell Y1eld
Y~. coli
&00
- 0.420
YYellow
• 0.460
Ymixed
- 0.472
400
.
Solids
... 300
Uptake
200
100
COD
o
o
JNaure
12.
2
4
6
8
10
12
Time (hours)
Growth response of a mixture of YeUow organism and
BacAericACa colt, K-12
ENGINEERING SCIENCE
2
I
10
~. pure
9
/-
8
..
6
0
Po
4
J.4
_/
D
/'
;7
//
tD
G)
:,.../
()
0
~----
2
CII
~
;:.
10
0
~~
"---
A
6
r-----
;'
///
...
./
_
o
_
-
oU-
Yellow, mixed _
---
J.~.
coli, mixed
:;/
1..0/
.... ~V"
""V
4xl07
o
Figure 13.
pure
/X- -
//
/v /~ ~
/
8
8
"'"
/'/
'/
/
..,/
r-4
r-4
r-4
I
2
4
6
8
10
.-
12
'1'1lll8 (hours)
Viable counts for Yellow organfam and 1I8cherichia.
in a mixed system
con, K-12
PROC. OF THE OKLA. ACAD. OF SCI. FOR 1966
600
r-----.,._----,....---...,.---------r-----,
Cell Yield
YSerratia - 0.478
500 "tlt--~---+----+_---
YYellow
- 0.462
Ymixed
- 0.496
400 t----\--;+----+----
~
• 300
t----t--+--\-~___+---f__--_+_--_+--___f
200 I-----"JI~--+__+----+_
100 t-----+-It--_""'-f~---~
o ......=;;.;:...._ _~:......;G,;;,lU;:,c;;,;o:;.:s;.;e;....;;CO~D
024
6
.1...
8
_l.
__'
10
1'1_ (hours)
Figure 14. Growth response of a mixture of Sen-atia marc68cens and Yellow orgatilMn
459
Ei"UINFmRING SCIENCE
2
I
Serratia, pure
-~---n--Serratia,
0.--"""
/
o
'/
~--+- ~/
4
~
2
~
~ 108 8
~
Q)
....
.0
....l'll
>
./""-
//U
~(/v
l0-/'
"-
.....
'_,
0
V
......
mixe(
~Yellow, pure _
/--
0
....
V--~f------If------t-----+----
&-----Ir-
__
.... ....
6
-
o
4
..............
..... ,
..... _ r..
_Yellow, lIlixed
2
o
Figure 15.
2
4
6
Tille (hours)
8
10
Viable count tor Serratia marcescem and Yellow organf8m in
a mixed system
PROC. OF THE OKLA. ACAD. OF SCI. FOR 1966
T
/0 Serratia
8
/
A
/
/
V
A
/'
/
.
!.~
7
/
-
1/
10'
8
8
~
~
/
/
/
V
/
...,,'0
~
2
FIgure 16.
"
6
8
10
12
Tl. . (hours)
Viable count tor Ben-atiG maTCeSCeM and Bscherlchia colil
K-12 in a mixed system
ENGINEERING SCIENCE
Cell Yield
YB1ue
600
- 0.697
YPseudomonas - 0.482
Ym1xed
- 0.630
500
400
300
200
100
l'----Q--t
COD
o
o
2.
a
4
6
Tille (hours)
Figure 17. Growth respoll8e of a
Pseudomotla8 aerugift03(1
mixture
of
Blue
organfMn
and
482
PROC. OF THE OKLA. ACAD. OF SCI. FOR 1966
2
t
/
9
10
..tv
8
T
6
i
,1
f"'4
f"'4
'~ V
U
f"'4
~
2
•'"
10
_0/1
~
~
-
-
--
~
--
lPseud1omonas, pure
;l~seudomonas,
mixed
Blue, pure
!nIue, mixed
0
rtl
fV
l7hl
8
~?
7
6
"x10
~
8
-
1/
,/1/
-,/ V
~~/
l ..
•
•
•
W
V
~
!/
7
o
Figure 18.
2
..
6
T1me (h6urs)
8
10
Viable count for Blue organism and Pseudomonas aeruginosa
In a mixed system
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Fawcett. H. S.
1981. The importance of investigation on the effects of
known mixtures of microorganisms. Phytopathol. 21 :545-550.
Jaaewtcz, L. and N. Porges. 1956. Biochemical oxidation ot dairy wastes.
Sewage and Ind. Wastes, 28: 1130-1186.
Jerla, J. S. and P. L. McCarty. 1965. The biochemistry of methane fermentation using Cl. tracers. J. Water Pollut. Contr. Fed., 87:178-192.
Monod. J. tIK9. The growth of bacterial cultures. Annu. Rev. Microbiol.
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Rao, B. S. and A. F. Gaudy, Jr. 1966. Effect of sludge concentration on
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Pollut. Contr. Fed., 38:'194-812.
RIch. L. G. 1983. U,"t Proceu68 01 8ataUary BngVaeering. p. 17.
John
WUey Ie Sons. Inc., New York.
sanborn. J. R. 1926. Physiological studies of assoclation. J. Bacterial.,
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ENGINEERING SCIENCE
488
Savastano, G. and H. S. Fawcett. 1929. A study of decay in citrus trults
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Sherman, J. M. and R. H. Shaw. 1921. Associative bacterlal action in
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Waksman. S. A.
organisms.
1937.
Associative and antagonistic effects of micro-
SoU Set, 43:51-68.
Wattle, E. 1942. Cultural characteristics ot zoolitlea-forming bacteria
isolated from activated sludge and trickling fnters. Public Health
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Wino~radsky,
d~ Paris.
H. 1935. Sur la microflore nltrifecatrlce des boues actives
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