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The processes of lactic acid production include two key stages, which are (a) fermentation and (b) product recovery. In this
study, free cell of Bifidobacterium longum was used to produce lactic acid from cheese whey. The produced lactic acid was then separated and purified from the fermentation
broth using combination of nanofiltration and reverse osmosis membranes. Nanofiltration membrane with a molecular weight cutoff
of 100–400 Da was used to separate lactic acid from lactose and cells in the cheese whey fermentation broth in the first step.
The obtained permeate from the above nanofiltration is mainly composed of lactic acid and water, which was then concentrated
with a reverse osmosis membrane in the second step. Among the tested nanofiltration membranes, HL membrane from GE Osmonics
has the highest lactose retention (97 ± 1%). In the reverse osmosis process, the ADF membrane could retain 100% of lactic
acid to obtain permeate with water only. The effect of membrane and pressure on permeate flux and retention of lactose/lactic
acid was also reported in this paper. 相似文献
2.
Abolghasem Shahbazi Michele R. Mims Yebo Li Vestal Shirley Salam A. Ibrahim Antrison Morris 《Applied biochemistry and biotechnology》2005,122(1-3):529-540
The performance of immobilized Bifidobacterium longum in sodium alginate beads and on a spiral-sheet bioreactor for the production of lactic acid from cheese whey was evaluated.
Lactose utilization and lactic acid yield of B. longum were compared with those of Lactobacillus helveticus. B. longum immobilized in sodium alginate beads showed better performance in lactose utilization and lactic acid yield than L. helveticus. In the spiral-sheet bioreactor, a lactose conversion ratio of 79% and lactic acid yield of 0.84 g of lactic acid/g of lactose
utilized were obtained during the first run with the immobilized L. helveticus. A lactose conversion ratio of 69% and lactic acid yield of 0.51 g of lactic acid/g of lactose utilized were obtained during
the first run with immobilized B. longum in the spiral-sheet bioreactor. In producing lactic acid L. helveticus performed better when using the Spiral Sheet Bioreactor and B. longum showed better performance with gel bead immobilization. Because B. longum is a very promising new bacterium for lactic acid production from cheese whey, its optimum fermentation conditions such as
pH and metabolic pathway need to be studied further. The ultrafiltration tests have shown that 94% of the cell and cheese
whey proteins were retained by membranes with a mol wt cutoff of 5 and 20 KDa. 相似文献
3.
The amount of corn stover and wheat straw that can be sustainably collected in North Carolina was estimated to be 0.64 and
0.16 million dry t/yr, respectively. More than 80% of these crop residues are located in the coastal area. The bioethanol
potential from corn stover and wheat straw was estimated to be about 238 million L (63 million gal/yr) in North Carolina.
The future location of ethanol plant in North Carolina was estimated based on feedstock demand and collection radius. It is
possible to have four ethanol plants with feedstock demand of 400, 450, 500, and 640 dry t/d. The collection radii for these
four ethanol plants are 46, 60, 42, and 67 km (28, 37, 26, and 42 miles), respectively. The best location for a bioethanol
plant includes four counties (Beaufort, Hyde, Tyrrell, and Washington) with feedstock demand of 500 t/d and collection radius
about 26 mile. 相似文献
4.
Numerical Algorithms - In this paper, we present two error bounds for the linear complementarity problems (LCPs) of locally doubly strictly diagonally dominant (LDSDD) matrices. The error bounds... 相似文献
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Actinobacillus succinogenes 130 Z was used to produce succinic acid from cheese whey in this study. At the presence of external CO2 supply, the effects of initial cheese whey concentration, pH, and inoculum size on the succinic acid production were studied.
The by-product formation during the fermentation process was also analyzed. The highest succinic acid yield of 0.57 was obtained
at initial cheese whey concentration of 50 g/L, while the highest succinic acid productivity of 0.58 g h−1 L−1 was obtained at initial cheese whey concentration of 100 g/L. Increase in pH and inoculum size caused higher succinic acid
yield and productivity. At the preferred fermentation condition of pH 6.8, inoculum size of 5% and initial cheese whey concentration
of 50 g/L, succinic acid yield of 0.57, and productivity of 0.44 g h−1 L−1 were obtained. Acetic acid and formic acid were the main by-products throughout the fermentation run of 48 h. It is feasible
to produce succinic acid using lactose from cheese whey as carbon resource by A. succinogenes 130 Z. 相似文献
6.
Abolghasem Shahbazi Yebo Li Michele R. Mims 《Applied biochemistry and biotechnology》2005,124(1-3):973-987
The FIRST (Feedstock Impregnation and Rapid Steam Treatment) approach was used in this study to isolate extractives, hemicellulose,
lignin, fibers, and cellulosic fines of softwood. With hydrolysis and fermentation of the hemicellulose and cellulosic fines
fractions, this approach produces four co-products: extractives, cellulose, lignin, and ethanol. The first unit operation
uses aqueous/alcohol to remove and recover the extractive rich fraction. The second unit operation uses steam treatment to
destructure the matrix and solubilize a large fraction of the hemicelluloses. The third unit operation uses alkaline delignification
to dissolve a lignin fraction. The fourth unit operation uses the refining process to separate fibers from cellulosic fines.
The fibers are bleached. The yields of lignin and bleached cellulose were about 20.0 kg and 38.3 kg out of 100 kg initial
dry pine, respectively. The recovered hemicelluloses were 23.3 kg (containing 16.1 kg hexoses and 5.0 kg pentoses) and the
cellulose fines derived hexoses amounted to 3.4 kg out of 100 kg initial dry pine. When the two liquors containing the hemicellulose
sugars and the cellulose fines-derived hexoses were fermented for ethanol production, an ethanol yield of 6.8 kg was obtained. 相似文献
7.
The separation of lactic acid from lactose in the ultrafiltration permeate of cheese whey broth was studied using a cross-flow
nanofiltration membrane unit. Experiments to test lactic acid recovery were conducted at three levels of pressure (1.4, 2.1,
and 2.8 MPa), two levels of initial lactic acid concentration (18.6 and 27 g/L), and two types of nanofiltration membranes
(DS-5DK and DS-5HL). Higher pressure caused significantly higher permeate flux and higher lactose and lactic acid retention
(p<0.0001). Higher initial lactic acid concentrations also caused significantly higher permeate flux, but significantly lower
lactose and lactic acid retention (p<0.0001). The two tested membranes demonstrated significant differences on the permeate flux and lactose and lactic acid retention.
Membrane DS-5DK was found to retain 100% of lactose at an initial lactic acid concentration of 18.6 g/L for all the tested
pressures, and had a retention level of 99.5% of lactose at initial lactic acid concentration of 27 g/L when the pressure
reached 2.8 MPa. For all the test when lactose retention reached 99–100%, as much as 64% of the lactic acid could be recovered
in the permeate. 相似文献
8.
Semicontinuous production of lactic acid from cheese whey using free cells of Bifidobacterium longum with and without nanofiltration was studied. For the semicontinuous fermentation without membrane separation, the lactic acid productivity of the second and third runs is much lower than the first run. The semicontinuous fermentation with nanoseparation was run semicontinuously for 72 h with lactic acid to be harvested every 24 h using a nanofiltration membrane unit. The cells and unutilized lactose were kept in the reactor and mixed with newly added cheese whey in the subsequent runs. Slight increase in the lactic acid productivity was observed in the second and third runs during the semicontinuous fermentation with nanofiltration. It can be concluded that nanoseparation could improve the lactic acid productivity of the semicontinuous fermentation process. 相似文献
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