Production of poly(3-hydroxybutyric acid) by fed-batch culture ofAlcaligenes eutrophus with glucose concentration control (original) (raw)
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High cell density fed-batch fermentation of Alreplacement applications Doi, caligenes eutrophus was carried out for the production 1990). Currently, ZENECA Bio Products produces coof poly(3-hydroxybutyrate) (PHB) in a 60-L fermentor. polymers of PHB/PHV through a bacterial fermentation During the fermentation, pH was controlled with NH 4 OH process under the trade name Biopol solution and PHB accumulation was induced by phos- Cox, 1994; Holmes, 1985). Despite PHA's advantages phate limitation instead of nitrogen limitation. The glucose feeding was controlled by monitoring dissolved oxyover other polymer materials as mentioned above, its gen (DO) concentration and glucose concentration in high production cost has hindered its performance in the culture broth. The glucose concentration fluctuated the market (Lee, 1996). Improving the productivity of within the range of 0-20 g/L. We have investigated the the fermentation process and developing an efficient effect of initial phosphate concentration on the PHB prorecovery process will make it economically more feasi-duction when the initial volume was fixed. Using an initial phosphate concentration of 5.5 g/L, the fed-batch fermenble (Hrabak, 1992; Lee, 1996). tation resulted in a final cell concentration of 281 g/L, a PHA is usually formed and stored in the form of PHB concentration of 232 g/L, and a PHB productivity of intracellular inclusion bodies under unfavorable growth 3.14 g/L и h, which are the highest values ever reported conditions Doi, 1990). For example, to date. In this case, PHB content, cell yield from glucose, and PHB yield from glucose were 80, 0.46, and 0.38% oxygen deprivation, nitrogen deprivation, sulfate limita-(w/w), respectively.
European Journal of Applied Microbiology and Biotechnology
A structured model is presented giving a mathematical description of batch cultures ofAlcaligenes eutrophus strain H 16 under chemolithoantotrophic growth conditions. A mass-spectrometer with a membrane inlet system was used to measure and control the concentrations of the dissolved gaseous substrates H2, 02 and CO 2. Growth and storage of PHB (Poly-/~-hydroxybutyric acid) H + are described as a function of the limiting substrate S (N 4), the residual biomass R, and the product P (PHB), Model parameters were evaluated by regression analysis followed by linearization. The differential equation model was solved numerically and compared with experimental data.
European Journal of Applied Microbiology and Biotechnology, 1979
Under chemolithoautotrophic growth conditions with the organism Alcaligenes eutropbus HI6 the exponential growth phase is characterized by two different growth rates, each associated with different specific rates of ammonium consumption. On the basis of the analytical determination of Poly-13-hydroxybutyric acid (PHB), it can be conclusively shown that PHB is synthesized even during the exponential growth phase at a specific rate proportional to the specific growth rates of total biomass. After complete consumption of ammonium, the increase of biomass is exclusively due to PHB synthesis, whereas protein and rest biomass (cell dry weight minus PHB) remain constant. After an extended period of fermentation, the PHB content reaches a saturation value. The transient phase between the growth and the storage phase is very short in comparison to the duration of the whole fermentation. In the case of Alcaligenes eutropbus, strain H 16, high concentrations of dissolved oxygen strongly influence growth as well as PHB synthesis.
Applied and environmental microbiology, 1995
We studied recovery of poly(3-hydroxybutyric acid) (PHB) from Alcaligenes eutrophus and a recombinant Escherichia coli strain harboring the A. eutrophus poly(3-hydroxyalkanoic acid) biosynthesis genes. The amount of PHB degraded to a lower-molecular-weight compound in A. eutrophus during the recovery process was significant when sodium hypochlorite was used, but the amount degraded in the recombinant E. coli strain was negligible. However, there was no difference between the two microorganisms in the patterns of molecular weight change when PHB was recovered by using dispersions of a sodium hypochlorite solution and chloroform. To understand these findings, we examined purified PHB and lyophilized cells containing PHB by using a differential scanning calorimeter, a thermogravimetric analyzer, and nuclear magnetic resonance. The results of our analysis of lyophilized whole cells containing PHB with the differential scanning calorimeter suggested that the PHB granules in the recombina...
Effects of Culture Conditions on Poly(β-Hydroxybutyric Acid) Production by Haloferax mediterranei
Applied and Environmental Microbiology, 1990
The halobacterium Haloferax mediterranei accumulates poly(β-hydroxybutyrate) (PHB) as intracellular granules. The conditions for PHB production in batch and continuous cultures have been studied and optimized. Phosphate limitation is essential for PHB accumulation in large quantities. Glucose and starch are the best carbon sources. With 2% starch, 0.00375% KH 2 PO 4 , and 0.2% NH 4 Cl in batch culture, a production of ca. 6 g of PHB per liter was reached, being 60% of the total biomass dry weight, and giving a yield over the carbon source of 0.33 g/g. The PHB production in continuous cultures was stable over a 3-month period. Our results demonstrate that H. mediterranei is an interesting candidate for industrial production of biological polyesters.
International Journal of Biological Macromolecules, 2010
We investigated optimization of poly(3-hydroxybutyrate) (PHB) production by Haloarcula sp. IRU1 in a batch culture system. Various batch experiments were carried out at different carbon source concentrations [glucose, at 1-8% (w/v)], phosphorus source concentrations [K(2)HPO(4), KH(2)PO(4), Na(3)PO(4) and Na(2)HPO(4) at 0.001-0.016% (w/v)], nitrogen source concentrations [NH(4)Cl, yeast extract, peptone and tryptone at 0.1-0.8% (w/v)] and temperatures [37-55°C]. By these experiments, optimum production conditions were determined using the Taguchi method. The results showed the highest PHB production by Haloarcula sp. IRU1 (63.0% of cell dry weight) in the presence of 2g/l glucose, 0.2g/l NH(4)Cl, 0.004 g/l KH(2)PO(4) and temperature (42°C). In overall, the results of this study showed that Haloarcula sp. IRU1 has a high potential for synthesis of PHB from glucose.
EFFECT OF GLUCOSE ON PHB PRODUCTION USING Alcaligenes eutrophus DSM 545 AND TISTR 1095
2012
Poly-β-hydroxybutyrate (PHB) is biodegradable plastics have received increased attention due to its properties that resemble those of petroleum-based plastics such as polyethylene. PHB could be accumulated within bacterial cells varying glucose concentration in the present study. The concentrations of 5, 10, 15 and 20 g L -1 glucose were employed as a single carbon source for the PHB production which compared between Alcaligenes eutrophus DSM 545 and A. eutrophus TISTR 1095. In shake flask culture, the maximum PHB concentrations were 9.437 g L -1 with 10 g L -1 glucose, and 1.679 g L -1 with 15 g L -1 glucose for A. eutrophus DSM 545 and A. eutrophus TISTR 1095, respectively. The highest PHB yield of 0.321 g PHB g -1 glucose was obtained from using 5 g L -1 glucose by A. eutrophus TISTR 1095. For A. eutrophus DSM 545, its highest PHB yield of 0.998 g PHB per g glucose was attainable from 10 g L -1 glucose. In addition, the production yield of PHB from A. eutrophus DSM 545 decreased ...
Effect of pH on the molecular weight of poly-3-hydroxybutyric acid produced by Alcaligenes sp
Biotechnology Letters, 1995
The molecular weight of a polymer is an important parameter characterizing the physical properties of the polymer. The effect of pH on the molecular weight of poly-3-hydroxybutyric acid (PHB) produced by Alcaligenes sp. K-912 were investigated. PHB having higher molecular weight was obtained when cultivated under high pH conditions compared to the results cultivated under low pH conditions. The polydispersity index was almost the same as 1.6. But the cell mass was decreased as the pH became higher. The molecular weight was mainly determined in the early cultivation period and molecular weight difference could be explained by calculating the number of polymer chains.
Production of polyhydroxybutyrate (PHB) by Alcaligenes latus using sugarbeet juice
Industrial Crops and Products, 2013
The practicality of using sugarbeet juice as medium to grow Alcaligenes latus (ATCC 29714) for production of polyhydroxybutyrate (PHB), a biodegradable plastic, was explored in this study. Dilute sugarbeet juice, sugarbeet juice with partial and complete addition of nutrients other than sugar were used as culture media. Media with partial nutrient addition was shown to be optimal for PHB production, with final dry cell weight (DCW) 10.30 ± 1.01 g/L, PHB concentration 4.01 ± 0.95 g/L, PHB content 38.66 ± 7.28%, Y p/x (g PHB produced per g dry cell weight) 0.39 ± 0.07 and a maximum PHB productivity of 0.22 ± 0.01 g/L h. The melting temperature of PHB extracted from sugarbeet juice-grown cells supplemented with partial nutrients was measured to be 151.46 • C with crystallinity of 43.12% and the corresponding crystallinity temperature of 45.42 • C. Thermal degradation of extracted PHB occurred from 255.14 to 283.69 • C with the degradation peak at 273.86 • C.
Macromolecules, 1996
The ability of poly(ethylene glycol)s, PEGs, to control poly(3-hydroxybutyrate), P3HB, molecular weight in a microbial fermentation polymerization process was studied using Alcaligenes eutrophus with fructose as the sole carbon source. PEGs varying in molecular weight and end group functionality were added to the cultivation medium subsequent to cell growth, and their effects on polymer formation were evaluated. In general, A. eutrophus showed substantial tolerance for PEGs. This was illustrated by similar viable cell concentrations for the medium without PEG, 10% (w/v) PEG-10 000 and 2% PEG-200. Furthermore, detrimental effects on polymer yields were not observed for concentrations of 5% PEG-106 and 10% PEG-10 000. The greatest reductions in molecular weight were obtained when relatively low molecular weight PEG was added to the medium. PEG-106 was most effective in that only 0.25% was required to reduce the number average molecular weight (Mn) by 74%. The largest decrease in P3HB Mn (from 455 000 to 19 400) was observed by adding 10% PEG-106 to the medium. The largest change in P3HB Mn per incremental addition of PEG occurred in the 0-1% PEG concentration range. Supplementing the incubation medium with the monomethoxy ether CH3O-PEG-OH-350 and PEG-300 resulted in almost identical molecular weight reductions. However, the dimethoxy ether of tetraethylene glycol was not an effective agent for molecular weight reduction. Therefore, interaction between PEG and the PHA production system leading to molecular weight reduction was enhanced for lower molecular weight PEGs and required at least one PEG chain end functionality which may be a hydroxyl group. It is believed that PEG interacts with the A. eutrophus synthase in such a way to increase the rate of chain termination by water relative to chain propagation reactions.