Pilot-Scale Production of Lactobacillus Rhamnosus Atcc 7469
The present study was undertaken in view of the demand for probiotic products as a result of health awareness in consumers and the lack of information pertaining to industrial probiotic production processes. Response surface methodology (RSM) was used to optimize the culture medium for the growth...
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my-upm-ir.472013-05-27T06:45:16Z Pilot-Scale Production of Lactobacillus Rhamnosus Atcc 7469 2004-12 Liew, Siew Ling The present study was undertaken in view of the demand for probiotic products as a result of health awareness in consumers and the lack of information pertaining to industrial probiotic production processes. Response surface methodology (RSM) was used to optimize the culture medium for the growth of a probiotic bacterium, Lactobacillus rhamnosus ATCC 7469. The factors studied were yeast extract, glucose, vitamins concentrations and initial culture pH. A polynomial regression model with cubic and quartic terms was used for analysis of the experimental data. RSM was found to be effective in developing an analysis model, finding the optimum point of the factors and assessing the effects of the factors. It was found that the effects involving yeast extract, glucose, vitamins and pH on the growth of L. rhamnosus were significant, and the strongest effect was given by the yeast extract concentration. Estimated optimum conditions of the factors for the growth of L. rhamnosus were as follows : pH = 6.9; vitamin solution = 1.28% (v/v); glucose = 5.01% (w/v) and yeast extract = 6.0% (w/v). iii Further improvement of cell production was made by using a process optimization approach. The fermentation parameters investigated were aeration, mixing, pH, inoculum size and temperature. Cell production and viability were greatly influenced by the culture pH and temperature compared to other parameters such as agitation speed. The optimal culture conditions for the cultivation of L. rhamnosus in the 2-L stirred tank fermenter were as follows : mixing speed, 0.69 ms-1; pH, 6.9; temperature, 37°C and inoculum size of 5% (v/v) in facultative condition. Under this condition, final cell viability obtained was 1.61 x 1010 CFU mL-1, viable cell yield and productivity were 3.20 x 1011 CFU gglucose -1 and 1.33 x 109 CFU mL-1 h-1, respectively. Unstructured models based on Monod and Luedeking-Piret equations were developed and found to be suitable to describe the cell growth, lactic acid production and substrate consumption by L. rhamnosus in batch cultivation in a shake flask, 2- L, 10-L and 100-L stirred tank fermenters. Lactic acid production was a growthassociated and non-growth-associated (mixed) process. Scaling-up on the basis of constant impeller tip speed resulted in increasing mixing time as fermenter working volumes increased, but the mixing times were still within the critical acceptable range as fermentation performance was not significantly affected. Continuous cultivation was used in an attempt to further improve biomass production of L. rhamnosus. The maximum specific growth rate, μmax, and the Monod cell growth saturation coefficient, Ks, were estimated at 0.4 h-1 and 0.25 g L- 1. Maximum cell viability (1.29 x 1010 CFU mL-1) was achieved in the dilution rate (D) range of D = 0.28 h-1 to 0.35 h-1, while both maximum viable cell yield and iv productivity were achieved at D = 0.35 h-1. Continuous cultivation of L. rhamnosus at D = 0.35 h-1 gave 267% improvement in viable cell count productivity as compared to batch cultivations. Results obtained from exponentially fed-batch cultivation of L. rhamnosus at a D = 0.4 h-1 indicated that this mode of cultivation might be a good alternative for L. rhamnosus production as higher cell concentration and lower lactic acid production could be achieved when compared to batch and continuous cultivations Lactobacillus - Molecular aspects Biotechnology 2004-12 Thesis http://psasir.upm.edu.my/id/eprint/47/ http://psasir.upm.edu.my/id/eprint/47/2/1000548939_t_IB_2004_4.pdf application/pdf en public phd doctoral Universiti Putra Malaysia Lactobacillus - Molecular aspects Biotechnology Institute of Bioscience English |
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Universiti Putra Malaysia |
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PSAS Institutional Repository |
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English English |
| topic |
Lactobacillus - Molecular aspects Biotechnology |
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Lactobacillus - Molecular aspects Biotechnology Liew, Siew Ling Pilot-Scale Production of Lactobacillus Rhamnosus Atcc 7469 |
| description |
The present study was undertaken in view of the demand for probiotic products as a
result of health awareness in consumers and the lack of information pertaining to
industrial probiotic production processes. Response surface methodology (RSM) was
used to optimize the culture medium for the growth of a probiotic bacterium,
Lactobacillus rhamnosus ATCC 7469. The factors studied were yeast extract,
glucose, vitamins concentrations and initial culture pH. A polynomial regression
model with cubic and quartic terms was used for analysis of the experimental data.
RSM was found to be effective in developing an analysis model, finding the
optimum point of the factors and assessing the effects of the factors. It was found
that the effects involving yeast extract, glucose, vitamins and pH on the growth of L.
rhamnosus were significant, and the strongest effect was given by the yeast extract
concentration. Estimated optimum conditions of the factors for the growth of L.
rhamnosus were as follows : pH = 6.9; vitamin solution = 1.28% (v/v); glucose =
5.01% (w/v) and yeast extract = 6.0% (w/v).
iii
Further improvement of cell production was made by using a process optimization
approach. The fermentation parameters investigated were aeration, mixing, pH,
inoculum size and temperature. Cell production and viability were greatly influenced
by the culture pH and temperature compared to other parameters such as agitation
speed. The optimal culture conditions for the cultivation of L. rhamnosus in the 2-L
stirred tank fermenter were as follows : mixing speed, 0.69 ms-1; pH, 6.9;
temperature, 37°C and inoculum size of 5% (v/v) in facultative condition. Under this
condition, final cell viability obtained was 1.61 x 1010 CFU mL-1, viable cell yield
and productivity were 3.20 x 1011 CFU gglucose
-1 and 1.33 x 109 CFU mL-1 h-1,
respectively.
Unstructured models based on Monod and Luedeking-Piret equations were
developed and found to be suitable to describe the cell growth, lactic acid production
and substrate consumption by L. rhamnosus in batch cultivation in a shake flask, 2-
L, 10-L and 100-L stirred tank fermenters. Lactic acid production was a growthassociated
and non-growth-associated (mixed) process. Scaling-up on the basis of
constant impeller tip speed resulted in increasing mixing time as fermenter working
volumes increased, but the mixing times were still within the critical acceptable
range as fermentation performance was not significantly affected.
Continuous cultivation was used in an attempt to further improve biomass
production of L. rhamnosus. The maximum specific growth rate, μmax, and the
Monod cell growth saturation coefficient, Ks, were estimated at 0.4 h-1 and 0.25 g L-
1. Maximum cell viability (1.29 x 1010 CFU mL-1) was achieved in the dilution rate
(D) range of D = 0.28 h-1 to 0.35 h-1, while both maximum viable cell yield and
iv
productivity were achieved at D = 0.35 h-1. Continuous cultivation of L. rhamnosus
at D = 0.35 h-1 gave 267% improvement in viable cell count productivity as
compared to batch cultivations. Results obtained from exponentially fed-batch
cultivation of L. rhamnosus at a D = 0.4 h-1 indicated that this mode of cultivation
might be a good alternative for L. rhamnosus production as higher cell concentration
and lower lactic acid production could be achieved when compared to batch and
continuous cultivations |
| format |
Thesis |
| qualification_name |
Doctor of Philosophy (PhD.) |
| qualification_level |
Doctorate |
| author |
Liew, Siew Ling |
| author_facet |
Liew, Siew Ling |
| author_sort |
Liew, Siew Ling |
| title |
Pilot-Scale Production of Lactobacillus Rhamnosus Atcc 7469 |
| title_short |
Pilot-Scale Production of Lactobacillus Rhamnosus Atcc 7469 |
| title_full |
Pilot-Scale Production of Lactobacillus Rhamnosus Atcc 7469 |
| title_fullStr |
Pilot-Scale Production of Lactobacillus Rhamnosus Atcc 7469 |
| title_full_unstemmed |
Pilot-Scale Production of Lactobacillus Rhamnosus Atcc 7469 |
| title_sort |
pilot-scale production of lactobacillus rhamnosus atcc 7469 |
| granting_institution |
Universiti Putra Malaysia |
| granting_department |
Institute of Bioscience |
| publishDate |
2004 |
| url |
http://psasir.upm.edu.my/id/eprint/47/2/1000548939_t_IB_2004_4.pdf |
| _version_ |
1747810155282563072 |