Environmental Engineering Reference
In-Depth Information
obtained with
B. longum
NCFB 2259 in a batch fermentation reactor using cheese
whey as the sole medium [62]. Lactic acid productivity was doubled during the 2
nd
and 3
rd
stages when a nanofiltration membrane was used to recycle lactose and cells
in a semi-continuous fermentation mode [62].
4.2 Starchy Biomass
The performance of LAB and fungi for lactic acid production from starchy biomass
is shown in Table 3. The maximum lactic acid volumetric productivity of 4.87 g/l
h
and yield of 0.97 g/g glucose were obtained from wheat with
Enterococcus faecalis
RKY1
after enzymatic liquefaction and saccharification [70]. A novel amylolytic
lactic acid strain
E. faecium
No. 78 also demonstrated high lactic acid productivity
of 3.04 g/l
·
h by a new continuous culture system with high cell density [28].
The filamentous fungus
Rhizopus
species has also attracted a great deal of atten-
tion not only because of its capacity to produce pure L (+) -lactic acid, but also due
to some advantages, including amylolytic ability, low nutritional requirement, and
easy downstream processing, with regard to the separation of the cell biomass from
the fermentation broth [75]. Lactic acid yield of 1.0 g/g glucose and productivity of
1.65 g/l
·
h were obtained from corn starch with immobilized
R. oryzae
NRRL 395
[59]. Lactic acid yield of 0.86 g/g and productivity of 1.3-1.6 g/l
·
·
h were obtained
by
R. arrhizus
DAR 36017 from waste potato starch [74].
Ta b l e 3
Performance of microorganisms and processes on lactic acid production from starch
crops
Yield (g/g
sugar)
Productivity
(g/l
Microorganisms
Substrate
Process
·
h)
References
E. faecium
No. 78
Sago
Continuous
3.04
[28]
E. faecalis
RKY1
Corn, Wheat,
Tapioca,
Potato
Batch
0.93-1.04 0.5-4.8
[69, 70]
Lb. delbrueckii
sp.
Delbrueckii
ATCC 9649
Wheat
Batch
0.82
1.6
[71]
Lb. delbrueckii
sp.
bulgaricus
ATCC
11842
Wheat
Batch
0.11
0.56
[71]
Lc. Lactis
sp.
Lactis
ATCC 19435
Wheat
Batch
0.76
3.0
[71]
Lc. Lacti
ssp.
Lactis
IFO 12007
Cassava
Recirculating, cell
immobilization
0.76
0.6
[72]
Lc. Lactis
sp.
Lactis
AS211
Wheat
Batch
0.77
1.7
[71]
R. oryzae
NRRL
395
Corn
Fed-batch/Cell
immobilization
≈
1
1.65
[59]
R. oryzae
RBU2-10 Rice
Batch/immobilized
1.84
[73]
R. arrhizus
DAR
36017
Potato
stirred tank
reactors
1.3-1.6
[74]
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