Fermentation optimization for the production of lovastatin by Aspergillus terreus: use of response surface methodology
01 Oct 2004-Journal of Chemical Technology & Biotechnology (John Wiley & Sons, Ltd)-Vol. 79, Iss: 10, pp 1119-1126
TL;DR: A Box-Behnken experimental design was used to investigate the effects of five factors (oxygen content in the gas phase, concentrations of C, N and P, and fermentation time) on the concentrations of biomass and lovastatin produced in batch cultures of Aspergillus terreus as discussed by the authors.
Abstract: A Box-Behnken experimental design was used to investigate the effects of five factors—ie oxygen content in the gas phase; concentrations of C, N and P; and fermentation time—on the concentrations of biomass and lovastatin produced in batch cultures of Aspergillus terreus. The values of the various factors in the experiment ranged widely, as follows: 20-80% (v/v) oxygen in the aeration gas; 8-48 g dm −3 C-concentration; 0.2-0.6 g dm −3 N-concentration; 0.5-2.5 g dm −3 phosphate-concentration; and 7-11 days fermentation time. No previous work has used statistical analysis in documenting the interactions between oxygen supply and nutrient concentrations in lovastatin production. The Box-Behnken design identified the oxygen content in the gas phase as the principal factor influencing the production of lovastatin. Both a limitation and excess of oxygen reduced lovastatin titers. A medium containing 48 g dm −3 C supplied as lactose, 0.46 g dm −3 N supplied as soybean meal, and 0.79 g dm −3 phosphate supplied as KH2PO4, was shown to support high titers (∼230 mg dm −3 )o f lovastatin in a7 -day fermentation in oxygen-rich conditions (80% v/v oxygen in the aeration gas). Under these conditions, the culture medium had excess carbon but limiting amounts of nitrogen. The optimized fermentation conditions raised the lovastatin titer by four-fold compared with the worst-case scenario within the range of factors investigated. 2004 Society of Chemical Industry
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TL;DR: In this paper, the marine diatom Gyrosigma sp. was cultured in a medium comprised of inorganic nutrients dissolved in palm oil mill effluent (POME) wastewater.
Abstract: The marine diatom Gyrosigma sp. was cultured in a medium comprised of inorganic nutrients dissolved in palm oil mill effluent (POME) wastewater. The production of lipids in the biomass was optimized using a statistical design of experiments in combination with the response surface method. The experimental factors were incident light level and initial concentrations of nitrate, phosphate, and silicate in the medium in batch culture. At 25 ± 2 °C, the maximum lipid content in the biomass harvested at the end of a 12-day batch culture was 70.7 ± 6.0% by dry weight for the following values of the experimental factors: an incident light level of 131 μmol photons m−2 s−1, a nitrate concentration of 1.8 mg L−1 (29.0 μM), a phosphate concentration of 6.8 mg L−1 (71.6 μM), and a silicate concentration of 10.1 mg L−1 (132.7 μM). Under the optimized conditions, the maximum dry mass concentration of the diatom was 560 mg L−1 on day 8 of a batch culture, declining to ~409 mg L−1 on day 12. For the 12-day batch operation, the final average productivities of the biomass and the lipids were 34.1 ± 5.5 mg L−1 day−1 and 24.1 ± 0.2 mg L−1 day−1, respectively. The fatty acids in the algal lipids were found to be as follows (%, w/w of total lipids): palmitic acid (48.6%), eicosapentaenoic acid (10.6%), myristic acid (8.1%), stearic acid (8.0%), linoleic acid (7.5%), oleic acid (6.4%), and linolenic acid (5.8%). The response surface model predicted the lipid content in the biomass with a high degree of confidence.
22 citations
TL;DR: In this paper, the authors used GC/MS and NMR analysis to identify β-glucan produced by A. pullulans M-2 as a polysaccharide of Dglucose monomers linked by β-(1→3, 1→6)-glycosidic bonds.
Abstract: β-(1→3)-D-glucans with β-(1→6)-glycosidic linked branches are known to be immune activation agents and are incorporated in anti-cancer drugs and health-promoting supplements. β-Glucan concentration was 9.2 g/L in a 200-L pilot scale fermentor using mutant strain Aureobasidium pullulans M-2 from an imperfect fungal strain belonging to A. pullulans M-1. The culture broth of A. pullulans M-2 had a faint yellow color, whereas that of the wild-type had an intense dark green color caused by the accumulation of melanin-like pigments. β-Glucan produced by A. pullulans M-2 was identified as a polysaccharide of D-glucose monomers linked by β-(1→3, 1→6)-glycosidic bonds through GC/MS and NMR analysis. When a conventional medium was used in the culture of A. pullulans M-2 in a 3-L jar fermentor, β-glucan concentration was 1.4-fold that produced by the wild-type. However, when a medium optimized by statistical experimental design was used with dissolved oxygen at 10%, the β-glucan concentration was 9.9 g/L with a yield of 0.52 (g β-glucan/g consumed sucrose), 2.9-fold that of the wild-type. This level of productivity was reproduced when the fermentation was scaled up 200-L. The industrial production of high β-glucan without melanin-like pigments is highly expected, as a health-promoting supplement or functional food.
19 citations
Cites methods from "Fermentation optimization for the p..."
...Box Behnken experimental design [21-23] was used to optimize the sucrose, rice bran, and sodium ascorbate concentrations in flask cultures....
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TL;DR: Glucoamylase from Aspergillus niger was used to hydrolyze the soluble sago starch to reducing sugars without any major pretreatment of the substrate.
Abstract: Glucoamylase (γ-amylase, EC 3.2.1.3) from Aspergillus niger was used to hydrolyze the soluble sago starch to reducing sugars without any major pretreatment of the substrate. A 2 L stirred tank reactor was used for the hydrolysis. The effects of pH, temperature, agitation speed, substrate concentration, and enzyme concentration on the reaction were investigated in order to maximize both the initial reaction velocity v and the final product yield Yp/s. A response surface methodology central composite design was used for the optimization. A maximum Yp/s of 0.58 g · g−1 and a high v of 0.50 mmoles · L−1 · min−1 were predicted by the response surface at the identified optimal conditions (61°C, a substrate concentration of 0.1% (w/v, g/100 mL), an enzyme concentration of 0.2 U · mL−1). The pH and agitation speed did not significantly affect the production of sugars. The subsequent validation experiments under the above-specified optimal conditions confirmed a maximum conversion rate and yield combination of 0.5...
17 citations
Cites methods from "Fermentation optimization for the p..."
...…been successfully applied to optimize fermentation processes (Maddox and Reichert, 1997; Chen, 1981; Grothe et al., 1999; Ratnam et al., 2003; Casas López et al., 2004), vegetable oil bioconversion (Cheynier et al., 1983), biomass production (Moresi et al., 1980), and numerous other processes…...
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...This method has been successfully applied to optimize fermentation processes (Maddox and Reichert, 1997; Chen, 1981; Grothe et al., 1999; Ratnam et al., 2003; Casas López et al., 2004), vegetable oil bioconversion (Cheynier et al., 1983), biomass production (Moresi et al., 1980), and numerous other processes (Panda et al., 1999; Ellaiah et al., 2002; Adinarayaan and Suren, 2005)....
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TL;DR: Sonication can be used to modify growth morphology and broth rheology without affecting growth rate and yield of filamentous fungi, according to a 25 l slurry bubble column sonobioreactor.
Abstract: Effects of ultrasound amplitude and duty cycle on cultures of Aspergillus terreus are reported in a 25 l slurry bubble column sonobioreactor. Fermentations were carried out batchwise. A 2 k -factorial design with added central points was used. Sonication at any cycle and amplitude level did not affect biomass growth rate and yield relative to nonsonicated control, but did affect growth morphology. Ultrasound disrupted fungal pellets and caused the biomass to grow mainly as dispersed hyphae. Production of lovastatin was reduced by medium- and high-cycle sonication. Sonication affected broth rheology. In view of these results, sonication can be used to modify growth morphology and broth rheology without affecting growth rate and yield of filamentous fungi.
15 citations
TL;DR: Biosynthesis of lovastatin (a polyketide metabolite of Aspergillus terreus) in bioreactors of different working volume was studied to indicate how the change of scale of the process influences the formation of this metabolite.
Abstract: Biosynthesis of lovastatin (a polyketide metabolite of Aspergillus terreus) in bioreactors of different working volume was studied to indicate how the change of scale of the process influences the formation of this metabolite. The experiments conducted in shake flasks of 150 ml working volume allowed to obtain lovastatin titres at the level of 87.5 mg LOV l -1 , when two carbon sources, namely lactose and glycerol were used. The application of the same components in a large stirred-tank bioreactor of 5.3-litre working volume caused a decrease of lovastatin production by 87% compared to the shake flask culture. The deficiency of nitrogen in this bioreactor did not favour the formation of lovastatin, in contrast to the small bioreactor of 1.95-litre working volume, in which lovastatin titres comparable to those in the shake flasks could be achieved, when organic nitrogen concentration was two-fold decreased. When the control of pH and/or pO2 was used simultaneously, an increase in lovastatin production was observed in the bioreactors. However, these results were still slightly lower than lovastatin titres obtained in the shake flasks.
15 citations
Cites background from "Fermentation optimization for the p..."
...Different results were obtained by Casas Lopez et al. (2004)....
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...The researchers who conducted lovastatin biosynthesis in bioreactors claimed that there were several factors that may have played an important role in these processes (Bizukojć and Ledakowicz, 2008; Casas Lopez et al, 2004; Lai et al., 2005; Rodriguez Porcel et al., 2006)....
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