Chemical Engineering June 2015 - 34

Technology Profile
Bio-based Methionine via Fermentation of Glucose
By Intratec Solutions
M
ethionine is an essential
amino acid that is not produced
by animals. Methionine
must be obtained
from dietary sources, and its major
use is as an animal nutritional-feed
additive. Methionine is mainly derived
from petrochemical sources. However,
biochemical routes to obtain it have
been researched. For instance, a joint
venture between CJ Bio (cjbio.net) and
Arkema (arkema.com) initiated methionine
production using both renewable
and petrochemical raw materials; and
Metabolic Explorer (metabolic-explorer.com),
in partnership with Roquette
(roquette.com), developed a process
for 100% bio-based methionine.
The process
The production of L-methionine via a
method similar to the one proposed in
patents issued to Metabolic Explorer
and Roquette is described below and
presented in Figure 1. In this process,
L-methionine is produced through a
fed-batch aerobic fermentation, using
glucose as the carbon source and
ammonium thiosulfate as the nitrogen
and sulfur source. Products obtained
from this process are L-methionine
powder (final product) and liquid Lmethionine
compound (byproduct).
Media preparation. Culture media
used in the fermentation are prepared
by mixing water, corn syrup (70 wt.%
glucose) and aqueous ammonium
thiosulfate solution in medium vessels.
Fermentation. A recombinant microorganism
produces L-methionine
through an aerobic fermentation proCorn
syrup
H2
Ammonium
thiosulfate
solution
Corn syrup
H2
Ammonium
thiosulfate
solution
6
2
Insoluble
impurities
Soluble
impurities
Water
purge
ST
Figure 1. Bio-based methionine production via the direct fermentation of glucose
34
CW
HCI
12
L-methionine
powder
L-methionine
liquid compound
CW
ST
13
14
1
Air
3
CW
5
4
ST
7
8
9
10
cess, which is divided into two phases:
batch and fed-batch. Fermenters
are filled with the batch medium, and
fermentation occurs until glucose exhaustion,
when the fed-batch phase is
started by adding the fed-batch medium
until the end of the fermentation.
Clarification and demineralization.
Culture broth is clarified by the removal
of insoluble and soluble organic
impurities by centrifugation and ultrafiltration,
respectively. Next, the broth
is demineralized using ion-exchange
resins to remove cations and anions.
Pre-concentration, crystallization
and filtration. L-methionine is concentrated
in an evaporator prior to
crystallization under vacuum by water
evaporation. Then, precipitated methionine
is sent to a vacuum filter, where
it is separated from the crystallization
mother liquor, which still contains dissolved
methionine.
Products recovery. Filtered L-methionine
is directed to a dryer, where Lmethionine
powder with 99.5 wt.% of
dry matter (90 wt.% of methionine) is
obtained. Evaporated water is sent to
a wash column before being used in
methionine washing during filtration.
Also, the crystallization mother liquor
is acidified with HCl, then concentrated,
resulting in the liquid L-methionine
byproduct, which contains 60 wt.% of
dry matter (22 wt.% of methionine).
Economic performance
An economic evaluation of the process
was conducted based on data
from Q1 2014. The following assumptions
were taken into consideration:
Water
purge
CW
CW
H2
11
n Africa n Central & South America n Middle
East n North Asia n North America n South Asia &
Oceania n West Europe
1,000
900
800
700
600
500
400
300
200
100
2010
2011
2012
2013
Figure 2. Methionine consumption by region
* A facility erected on the U.S. Gulf
Coast with a nominal capacity of
87,600 ton/yr of L-methionine powder
and 86,700 ton/yr of liquid
* Storage autonomy of 15 d for feedstock
and 20 d for products
Estimated capital investment (total
fixed investment, working capital and
initial expenses) is about $430 million,
and operating expenses are about
$3,900/ton of L-methionine powder.
Global perspective
Historical methionine-consumption is
presented in Figure 2. Globally, Western
Europe, North America and North
Asia are the major consumer regions.
While most regions had similar growth
in methionine consumption (average
growth rates around 5%/yr), North Asia
stands out at 11%/yr. n
Edited by Scott Jenkins
Editor's Note: The content for this column is supplied by
Intratec Solutions LLC (Houston; www.intratec.us) and edited
by Chemical Engineering. The analyses and models presented
are prepared on the basis of publicly available and nonconfidential
information. The content represents the opinions
of Intratec only. More information about the methodology for
preparing analysis can be found, along with terms of use, at
www.intratec.us/che.
To flare
1) Batch medium vessels
2) Fed-batch medium
vessels
3) Fermenters
4) Broth centrifuges
5) Ultrafiltration unit
6) Ion-exchange unit
7) Evaporator
8) Vacuum crystallizer
9) Vacuum filter
10) Vacuum dryer
11) Vacuum wash column
12) Liquid methionine
concentrator
13) Cooling tower
14) Steam boiler
CW Cooling water
ST Steam
ChemiCal engineering www.Chemengonline.Com june 2015
http://www.cjbio.net http://www.arkema.com http://www.er.com http://www.roquette.com http://www.intratec.us http://www.intratec.us/che http://www.Chemengonline.Com
Chemical Engineering June 2015

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