Biomedical Engineering Reference
In-Depth Information
Table 7.1
2,3-Butanediol-producing strain levels [
82
]
Maximum yield (g L
1
)
Yield (g g
1
)
Strains
Carbon source
Aerobacter aerogenes
Glucose
36.5
0.30
Bacillus amyloliquefaciens
Glucose
30
0.33
Bacillus licheniformis
Glucose, sucrose,
and starch
5.16
0.44
Bacillus polymyxa
Glucose
13
0.29
Bacillus polymyxa
Starch
38
0.28
Paenibacillus polymyxa
Glucose
-
-
Enterobacter aerogenes
Glucose
110
0.48
Enterobacter cloacae
Glucose, xylose,
and arabinose
(corn fiber)
34.4
0.43
Klebsiella oxytoca
Xylose
49
0.33
Klebsiella oxytoca
Molasses
98.6
0.48
Klebsiella pneumoniae
Whey
13.7
0.39
Klebsiella pneumoniae
Glucose
39.6
0.43
Serratia marcescens
Sucrose
-
-
However, the main problem limiting the industrialization of bio-based 2,3-
butanediol is the high economic cost. Future works remain to be carried out,
including the following aspects [
55
,
56
]:
1.
Strains
. An emphasis is on strains, focusing on strains that are able to directly
use the hydrolyzate of lignocellulose, are suitable for high-density culture, and
produce less by-product.
2.
Substrate
. For a natural renewable resource, lignocellulose as a carbon source
instead of the glucose currently used has strong economic feasibility, but the
lack of an effective technology to separate different components and the high
cost of cellulase both result in difficulty of 2,3-butanediol industrialization using
lignocellulose.
3.
Stereo-specific mechanism
. There are three kinds of stereoisomers of 2,3-
butanediol, and its corresponding metabolic enzymes also are highly stereo-
specific. It will also be a research focus in the future to clarify the stereo-specific
mechanism in the catalytic process and improve optical activity and the purity of
the target product.
4.
Separation and extraction
. The cost-effective separation of 2,3-butanediol has
been an important reason to limit its large-scale industrial production. 2,3-
Butanediol has some properties, such as a high boiling point, high hydropho-
bicity, and other impurities in the fermentation broth, that make the purification
process difficult. Therefore, the development of a high-efficiency, low-cost
separation and extraction process is the key to reduce production costs and
expand the production scale.
5.
Process
. New technology and optimization of the fermentation process should be
further explored. To minimize the middle process, the emphasis is on effectively
reducing the cost while improving the target product yield.
