Note: Descriptions are shown in the official language in which they were submitted.
WO 2023/050125
PCT/CN2021/121610
POLYALKYLENE ALKYL COMPOUND FOR DEFOAMING FERMENTATION BROTH
FIELD
This invention relates to a method of inhibiting the formation of foam in
industrial
processes such as in fermentation broths.
INTRODUCTION
Foam is generated in almost any industrial process where a liquid, gas, foam-
stabilizing
surfactants and agitation are present. In most cases, foam is undesirable,
especially in
fermentation industry. Foaming is a nuisance during fermentation process
because it causes
process control issues and reduces the mechanical efficiency. For example, the
existence of foam
in fermentation tank may result in a prolonged fermentation cycle, reduce
production capacity,
waste raw materials, affect bacterial respiration, cause bacterial infection
and may affect the
quality of the finished products.
Current methods to control foam include mechanical means such as the use of
baffles and
mixing control systems. In conjunction, chemical defoamers or antifoamers are
often used.
There are different classes of additives used in prevention, removal and
mitigation of foam
formation that work via differing mechanisms and are effective for different
foam types (e.g.
macro vs micro foams). While in principle these classes differ, the terms used
to define them are
often used interchangeably. In addition, many, if not most additives, do not
solely perform only
one function.
Antifoamcrs are additives that prevent or inhibit foam formation from the
outset, and are
typically added to a potentially foaming solution prior to foam formation.
Defoamers are
compounds that are added to mixtures in order to destroy foam that has already
been generated,
targeting surface foam (macro foam) and aiming to bring about rapid foam
collapse. Deaerators
function in a manner similar to defoamers, also aiming to destroy foam that
has already been
generated, but they target sub-surface foam (micro foam). Well known
defoamers, antifoamers
and deaerators include amongst others, silicone oils as well as block
copolymers of lower
alkylene glycols.
There is however an ongoing need for improved stable, simple, low cost,
aqueous
defoamers, antifoamers and / or deaerators in concentrated form for effective
application in the
chemical, household and industrial process industries.
SUMMARY
The present invention relates to a method for inhibiting the formation of foam
in a
process comprising the step of adding an effective amount of a foam control
agent to a process
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mixture. The foam control agent comprises a compound that can be represented
by the formula,
RO(E0).(PO)n,H, where R is a linear hydrocarbon radical having from 12 to 18
carbon atoms;
EO is ethylene oxide; PO is propylene oxide; n can be any integer from 2 to 9;
and m can be any
integer from 8 to 19. Furthermore, the compounds can be characterized in that
the molecular
weight of R is from 10 to 29 percent by weight of the compound. These
compositions have been
found to be superior in controlling foam formation versus conventional
antifoamers in
fermentation, preferably in amino acids fermentation and enzyme fermentation,
more preferably
in lysine, MSG and glucose oxidase fermentation.
DETAILED DESCRIPTION
The present invention has utility in any process where a liquid and a gas are
present and
agitation or other means of surface interaction between the liquid and gas is
present, as under
such conditions foam has a tendency to be generated. In particular, the
present invention has
been found to have utility in controlling foaming in a fermentation broth. For
purposes of this
invention, "fermentation broth" means an aqueous dispersion of nutrients
usually with
microorganisms, from which a metabolic product is ultimately extracted. The
microorganisms
are preferably bacteria or fungi or yeast. Typical nutrients seen in
fermentation comprise a
source of carbon, nitrogen, salts, and organism- specific requirements.
Typical carbon sources
include monosaccharides, disaccharides, polysaccharides, alcohols, carboxylic
acids, fats, and
hydrocarbons. Nitrogen sources often also include carbon, and are exemplified
by ammonia,
urea, bean meal, grain meal, seed meal, fish meal, cornsteep liquor, and yeast
extracts. Salts can
be specifically added to the fermentation broth as well.
The method of the present invention comprises the step of adding an effective
amount of
a foam control agent to a process mixture. The foam control agent comprises a
compound that
can be represented by the formula, RO(E0)õ(P0),,,H, where R is a linear
hydrocarbon radical
having from 12 to 18 carbon atoms; E0 is ethylene oxide; PO is propylene
oxide; n can be any
integer from 2 to 9 inclusive; and m can be any integer from 8 to 19
inclusive. Furthermore, the
compounds can be characterized in that the molecular weight of R is from 8 to
29 percent by
weight of the compound.
While R is a linear hydrocarbon radical having from 12 to 18 carbon atoms for
many
applications it may be preferred that R be from 16 to 18 carbons. Similarly,
while m can be an
integer from 8 to 19, for some applications it may be preferred that m at
least 10, or even 12 up
to 17 or even 15. Likewise, while n can be any integer from 2 to 9, or some
applications it may
be preferred that n be at least 3, or even 4 up to 8 or even 7.
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For many applications it may be desirable to choose R, m and n such that the
molecule as
a molecular weight of from 600 to 3000 grams per mole, preferably 710 to 1800
grams per mole,
more preferably 900 to 1200 grams per mole.
The number of carbons in the R group should be selected so that the molecular
weight of
R represents from 8 to 29 percent by weight of the compound, more preferably
from 12, 15 or
even 18 to 27, 25 of even 23 percent by weight of the compound.
The preferred foam control agents for use in the present invention can also be
characterized by their cloud point, which can be determined according to ASTM
D2024.
Preferably the cloud point will be from 10 C to 30 C, more preferably from 10
C to 25 C.
As will be readily understood from the formula, the foam control agents for
use in the
present invention are fatty alcohol initiated alkoxylates. Such materials can
be prepared
according to methods well known in the art, such as were propoxylating and
ethoxylating
alcohols of the formula ROH (where R is a linear hydrocarbon radical having
from 12 to 18
carbon atoms, as for the foam control agent formula) utilizing well-known
alkoxylation catalysts
such as double metal cyanide (DMC) or KOH catalysts. Each alcohol product was
targeted to
consist of between 8 to 19 moles of propylene oxide and 2 to 9 mole of
ethylene oxide. The
alcohols can be advantageously ethoxylated using purified ethylene oxide at
150-160 C and 40-
60 psig in a single, continuous run and then propoxylated using purified
propylene oxide at 130-
150 C and 40- 60 psig in a single, continuous run.
The foam control agents of the present can be added to the target process
mixture (such
as fermentation broth) in any amount which is effective to prevent and or
break down foam
occurring in the mixture. Typically, this may be in an amount from 1 to 5000
ppm, preferably
from 5 to 3000 ppm, even more preferably from 10 to 2500 ppm, or even 100 to
2000 ppm by
weight of the process mixture.
It has been found that foam control agents for use in the present invention
are particularly
effective with the process mixture is at a temperature of from about 25 C to
about 45 C.
In another aspect of the present invention, the foam control agent is added to
the process
mixture as part of a formulation which may comprise, (in addition to the foam
control agent
described above) one or more of the following components: water, additional
foam control
agents (including other control agents which fall within the formula described
above), seed oils,
mineral oils, wax, surfactants and silicones. Other surfactants which may be
added include other
materials sold under the DowfaxTm-tradernark including DowfaxTM 146, DowfaxTm-
144,
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DowfaxTm-142, DowfaxTm-122, DowfaxTm-123, DowfaxTM-114, DowfaxTm-111, DowfaxTm-
117,
DowfaxTm-163, DowfaxTm-105, and DowfaxTm-107.
EXAMPLES
To demonstrate the effectiveness of the present invention, a commercial Luria
Broth
(-LB broth") is used as a standard foaming medium to evaluate foam control
agent performance.
The fermentation broth solution is prepared by simply dissolving LB Broth
Miller in deionized
water. LB Broth Miller is supplied by BD Co., Ltd. The LB Broth Miller is
reported to contain
Tryptone, Yeast extract and Sodium Chloride. The fermentation broth solution
is prepared by
simply dissolving LB Broth Miller into deionized water in the concentration
reported in the
tables. No additional microorganism, such as bacteria or fungi or yeast, is
added and no
sterilization process is applied since the formulation is not intentionally
inoculated. Two
suppliers of LB broth were utilized for the study. Examples 1-13 and the
blanks (unless
otherwise noted) were using LB broth from Thermo Fisher Scientific Inc. (lot
200806082408).
Examples 3-2 and Comparative Examples 1-11 and one blank as noted were tested
on LB broth
from BD Co., Ltd. (lot 5114604).
The evaluation of foam control agent performance is determined by using Foam
scan
instrument, which mimics a fermentation tank in an industrial fermentation
process by providing
a settled airflow speed and temperature. The foaming properties and foam
stability are observed
and evaluated by optical characteristic (by image analysis). The volume of
foam vs time can be
read out by default.
The foam control performance is evaluated by the following procedures:
First 5g (or 2.5 g) of the LB Broth Miller is added into 100 mL deionized
water to get the
50 g/L (or 25g/L) fermentation broth solution reported in Table 1.
Then the indicated amount of foam control agent is added into 100 g of the
fermentation
broth solution to get the formulation for foam testing.
Next the temperature of the Foamscan water bath is set to the indicated
temperature
(30 C or 35 C or 40 C).
Then 60 mL of the testing solution is injected into a 260 nil sample tube.
When the solution is heated to the target temperature, the test begins by
starting the gas
(compressed air) bubbling through the solution at a flow rate of 450mL/s.
The foam volume is measured at every 15 seconds up until 300 seconds in total.
As the
sample tube is 260 ml, foam measurements in excess of 200 ml could not be
made.
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Table 1 . Innovative examples and comparative examples
Mw Cloud I:I: wiiitt6
:1::::;,:p.:44t.iiii.ti.60m.ltfe4:1:4-44.44-.
Iriiiiiiiiii::::i:viiiiiiiiiiiiiiiiiii:1::::!
..,......,,,,..iyi::,.-7::::::::
,,====:iyiyiy:....:+i.i.
04.0Ci i;i;i;i;i;i;i;i;ii;i;i;i;
i;i;i;i;i;i;i;iNiAtioto$,..oi;i;i;
i;i;i;i;i;i;ii;i;i;i;i;i;i;ii;i;i;i;i;i;i;i;i;i;:;:;:
:;:;:;iffikiii0:;:;:;:;;;:;:;:;:;:;:;:;:;:;i;i;i;i;i00.004ii;ii;i;i:;:;:;
Innovative 1200 13 17% C16-18 + 4 mol E0+õ100õppmõõõõõõ 30 C
=:==
Example 1 14 mol po
Innovative 1-200 13 17% C16-18 + 4 mol EO + 200 ppm 30 C
LIF1 W ::6Ø40tX
Example 2 14 mol po
Innovative = 1200 13 17% = C16-18 + 4 mol EO + 300 ppm 30 C
:=1:.:.:.õ.:.:.õLWBroth 50g/L
Example 3. 14 mol PO
Innovative 1200 :13:::-,-, 17% C16-18
+ 4 mOLE0 +::::::::::100::ppm :35 C
LB Broth 50g/L
Example 4 14 mol PO
.:..:.:.:.:..:.:.:.:.:.:.:.:.:.:.:...:.:.:.
Innovative 1200 13 17% C16-18 + 4 mol E0
+:::::::::2013:4111 35 ct
LB Broth 50g/L
Example 5 14 mol PO M]M]M]-
Innovative 1200 13 17% C16-18 + 4 mol EO + -? 300 Rim 35
C
LB Broth 50g/L
Example 6 14inlP0:
Innovative 1200 = 13 17% C16-18 + 4 mol EO + 100 ppm 40 C
L13 Bmth 50g/L
Example 7 101 1 PO
Innovative 1200 13 17% CW18 + 4 mol EO + 200 ppm 40 C
LB Broth 50g/L
Example 8 14 mol PO
Innovative 1200 13 17% C16-18 + 4 mol EO + 300 ppm 40 C
LB Broth 50g/L
Example 9 14 mol pcs
Innovative 1200 13 17% C16-18 + 4 mol EQ +a::,300 ppm 30 C
LB Broth 25g/L,
Example 1.0 14 mol PO
Innovative- 1200 13 17% C16-18 + 4 mol EO + 300 ppm 35 et
LB Broth 25g/L
Example 1-1 14 mol po
Innovative : 1200 13 17% C16-18 + 4 mol Ep + 300 ppm 40 C
LB Broth 25
Example :12 14 mot TOM:::::: :
Innovative:- 1170 .14 15% C12-15 + 6 mol
Et) + 300 ppm 30 C
LB Broth 50g/L
Example 13 12 mol po
Comparative 2000 1743 8% C16-18*40 mol PO + 300 ppm 30 C
LB Broth 50g/L
Example 1 3 .mol EO
Comparative 2000- 26 8% C12 + 10 mol EO + 300 ppm 30
C
LB Broth 50g/L
Example 2 3000 22.5 mol PO--------- :
Comparative 1900 10 4% C12-14 +12 mol EO + 300 ppm 30 C
LB Broth 50g/L
Example 3 55::mol PO
Comparative 4650 18 - Glycerine +69 mol PO 300 ppm 30 C
Example 4 +:::13 mol EO LB
Broth 50g/L
Comparative 3000 16 -
Glycerine + 50 mol PO 300 ppm 30 C
LB Broth 50g/L
Example 5
Comparative 4000 40 - Glycerine + 30.5 mol 300 ppm 30 C.
LB Broth 50g/L
Example 6 E0+40 PO
Comparative 3550 -----------20.5 -
0.4f0e4tie + 133 mol 300 ppm 30 C
Example 7 EO +66.5 mol PO LB
Broth 50g/L
Comparative 4500 10 - 11.s.Vt 69 mol PO + 9 300 ppm 30 C
LB Broth 50g/L
Example 8
Comparative 13000 32 - Sorbito149.7.4fliol EO 300 Om 30 C
LB Broth 50g/L
Example 9 +132 mot-P0:-:-:-:-:
Comparative 1900 23 - 2.3 mo11314.4 31 mol 300 ppm 30 C
LB Broth 50g/L
Example 10 PO + 2.3 itibl EO
Comparative 2640 22 - 19.4 mol PO + 8.4 mol 300 ppm 30 C
LB Broth 50g/L
Example 11 E0+ 19.4 PO
The results of this evaluation are presented in Table 2:
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Table 2
105 120 135 150 165 180 195 210 225 240 255 270 285 300
Foam volume (mL) 3 s15 s 30 s 45 s 60 s 75 s 90 ssss s
ssssssss ss
Blank (i.e., No
FCA) at 30 C,
50g/L LB Broth
15 50 86 116 131 139 149 160 154 154 155 156 154 156 160 159
161 161 162 165 164
Blank at 30 C,
25g/L LB Broth
19 71 119 145 153 161 163 165 167 169 169 168 171 173 170 170
170 170 173 173 172
Blank at 35 C,
50g/L LB Broth
10 40 68 94 109 125 131 138 145 143 143 142 153 149 153 154
156 156 154 156 160
Blank at 35 C,
25g/L LB Broth
9 37 63 75 85 92 93 92 93 93 92 91 93 91 90 90 90 90 90 89 88
Blank at 40 C,
50g/L LB Broth
9 34 62 92 112 126 128 137 146 147 144 147 147 151 150 152
156 153 153 154 153
Blank at 40 C,
25g/L LB Broth
9 34 59 75 82 85 86 82 82 82 80 80 80 79 79 78 79 78 77 76 75
Innovative
Example 1 7 8 8 8 8 8 8 8 8 8 8 8
8 2 8 8 8 8 8 8 8
Innovative
Example 2 7 8 8 8 7 8 7 8 7 7 7 8
8 8 7 7 8 7 7 8 8
Innovative
Example 3
6 5 6 6 5 5 5 5 5 5 5 6 5 6 4 6 6 5 5 6 5
Innovative
Example 4 7 8 8 9 8 8 8 8 8 8 8 8
7 8 8 8 8 8 8 8 8
Innovative
Example 5 5 6 5 6 5 5 5 5 4 6 5 5 4 3 5 5 5
4 5 5 6
Innovative
Example 6 6 5 5 5 5 5 5 5 5 5 5
6 5 5 6 6 5 5 5 5 6
Innovative
Example 7 8 8 8 8 8 8 8 8 8 8 8 8
8 8 8 8 8 8 8 8 8
Innovative
Example 8 8 6 6 7 7 6 7 6 7 6 7 6 6 7 6 7 6
8 6 6 6
Innovative
Example 9 5 5 6 6 5 5 5 4 4 4 5 5
5 5 5 6 5 4 4 5 5
Innovative
Example 10 5 6 5 5 5 3 4 5 5 5 5
4 4 5 4 4 5 5 5 5 5
Innovative
Example 11 5 4 5 5 3 5 4 5 5 5 6 4
5 5 3 3 3 5 5 4 5
Innovative
Example 12 5 6 5 5 5 5 5 5 4 4 4 5
5 6 3 4 5 4 4 3 5
Innovative
7 10 10 10 10 10 10 10 11 11 11 11 11 11 11 11 11 11 11 11 11
Example 13
Blank(No FCA ) at
30 C, 50g/L LB
from BD Co., Ltd. 11 47 87 124 142 153 162 167 171 177 184 189 195 194 195 196
196 196 195 195 195
Innovative
Example 3-2 (using
LB from BD Co.,
Ltd.)
7 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8
Comparative
Example 1
10 17 24 27 30 30 32 33 32 33 36 36 38 40 40 38 40 40 41 42
43
Comparative
Example 2
6 17 26 34 39 43 44 45 46 47 47 48 49 49 50 50 50 51 51 52 52
Comparative
Ex ample 3 6 10 10 10 10 10 10 10 10
9 10 10 10 10 10 10 10 10 10 10 10
Comparative
Example 4 7 10 9 10 10 9 10 10 10 10
10 10 10 10 11 11 10 11 10 10 9
Comparative
9 27 44 58 66 71 69 69 71 69 71 72 74 73 73 75 75 78 78 75 76
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Example 5
Comparative
Example 6
15 37 49 59 67 69 71 72 72 72 72 72 74 76 78 78 78 77 77 76
76
Comparative
Example 7
10 14 13 14 14 15 15 15 15 15 15 15 15 15 15 15 15 16 16 16
16
Comparative
Example 8
6 12 13 12 13 13 13 10 15 14 14 16 16 17 18 23 24 26 25 28 29
Comparative
Example 9
12 39 66 93 108 115 131 143 153 153 153 161 172 166 167 166
184 181 178 186 184
Comparative
Example 10
10 26 41 56 66 76 82 85 87 89 91 92 93 93 93 93 93 93 93 94
94
Comparative
Example 11
10 20 23 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 24 25
24
From the results in Table 2, it can be seen that the innovative examples have
comparable
or better foam control performance than all comparative examples in LB broth.
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