High-yield production of maltooligosaccharide-forming α-amylase in Bacillus subtilis.

Application of a statistical design to the optimization of culture medium for α-amylase production by Aspergillus niger ATCC 16404 grown on orange waste powder

Fermentation optimization for the production of bioactive polysaccharides from Cordyceps sinensis fungus UM01

Optimization of fermentation medium for succinic acid production using Basfia succiniciproducens

Rice straw is one of the potential economic feedstock for biobutanol production through ABE fermentation. However, the rice straw hydrolysate-based fermentation medium needs to be supported with nutritional elements. In this study, an attempt is made to optimize the rice straw hydrolysate-based fermentation medium employing Clostridium acetobutylicum MTCC 481 using Taguchi design of experiments (DOE) statistical model. Initially, a set of 12 nutrient components viz. MgNO3·6H2O, FeNO3, NH4NO3, yeast extract, PABA, biotin, PABA + biotin mixture, CaCl2, KCl, NaCl, MgSO4 and CH3COONa were screened through classical (one-variable-at-a-time) method. Based on the results, four components (PABA, yeast extract, MgSO4 and CH3COONa) were found to have significant impact, and were further subjected to statistical optimization through Taguchi DOE method. These experiments revealed that RSH supported with 3 g L−1 of yeast extract and 4 mg L−1 PABA to RSH was the most optimum fermentation medium. Experiments using 2 L bioreactor with this optimum fermentation medium showed nearly complete utilization of soluble sugars with the production of 8.7 g L−1 of total solvents and 6 g L−1 of butanol. The experimental data were fitted to kinetic models reported in the literature to determine the kinetic parameters of the fermentation process. An interesting result was revealed from this analysis that the under optimized fermentation medium, the kinetic parameters for both shake flask and bioreactor level were similar. This essentially means that effect of scale of operation is rendered insignificant when fermentation medium is under optimum conditions.Electronic supplementary materialThe online version of this article (doi:10.1007/s13205-013-0120-x) contains supplementary material, which is available to authorized users.

The aim of this study was to enhance the production of vitamin K2 by using N-methyl-N-nitro-N-nitroso-guanidine (NTG) and low energy ion beam implantation and optimizing the fermentation medium. Mutation resulted in 1.66-fold higher production of vitamin K2 than that of the parentl strain. The production by the mutant BN-P15-11-1was increased 55% and reached 3.593±0.107 mg/L by using the Plackett-Burman and Box-Behnken designs to optimize the fermentation medium. The optimal fermentation culture medium was composed of (g/L) glycerol 69.6, sucrose 34.5, K2HPO4 4.0, peptone 20, yeast extract 25 and fermented at 37 °C and 150 rpm for 72 h. The results showed that the NTG and low energy ion beam implantation mutations and optimizing fermentation medium were effective methods to enhance vitamin K2 production.

The aim of this study was to enhance the production of vitamin K2 by using N-methyl-N-nitro-N-nitroso-guanidine (NTG) and low energy ion beam implantation and optimizing the fermentation medium. Mutation resulted in 1.66-fold higher production of vitamin K2 than that of the parentl strain. The production by the mutant BN-P15-11-1was increased 55% and reached 3.593±0.107 mg/L by using the Plackett-Burman and Box-Behnken designs to optimize the fermentation medium. The optimal fermentation culture medium was composed of (g/L) glycerol 69.6, sucrose 34.5, K2HPO4 4.0, peptone 20, yeast extract 25 and fermented at 37 °C and 150 rpm for 72 h. The results showed that the NTG and low energy ion beam implantation mutations and optimizing fermentation medium were effective methods to enhance vitamin K2 production.

Biocatalytic conversion of CO to acetic acid by Clostridium aceticum—Medium optimization using response surface methodology (RSM)

Hexanoic acid (HX) is a crucial flavor compound and precursor of ethyl caproate (EA), which determines the quality of Chinese Luzhou-flavor liquor (CLFL). The isolation, purification, identification, and optimization of fermentation conditions of HX-producing bacteria are essential for industrial CLFL production. In this study, one strain of HX-producing bacterium was isolated from six candidate bacterial strains and identified as Clostridium sartagoneforme. Then, the growth characteristics and HX production of C. sartagoneforme were investigated. Sodium acetate medium was identified as the optimal fermentation medium from four candidate media. C. sartagoneforme yielded 800.85 ± 12.87 mg/100mL HX in sodium acetate medium. Then, to further optimize the formula of the fermentation medium, the carbon and nitrogen sources and inorganic salt component of the fermentation medium were investigated using HX yields as an optimization index. Optimization was performed with a single-factor experiment and the Taguchi design method. The single-factor experiment showed that the highest HX outputs were obtained when the sodium acetate medium contained 2.5 g/L yeast extract, 1.8 g/L KCl, 20 g/L sodium acetate, 15 mL/L ethanol, and 1.5 g/L glucose. In the orthogonal experiment designed using the Taguchi design method, HX yields reached 2018.29 ± 46.37 mg/100mL in sodium acetate medium that contained 3.5 g/L yeast extract, 1.8 g/L KCl, 25 g/L sodium acetate, and 15 mL/L ethanol.

Production of an endopolygalacturonase from Wickerhanomyces anomalus with disintegration activity on plant tissues

This study was conducted to enhance the production of tacrolimus in Streptomyces tsukubaensis by strain mutagenesis and optimization of the fermentation medium. A high tacrolimus producing strain S. tsukubaensis FIM-16-06 was obtained by ultraviolet mutagenesis coupled with atmospheric and room temperature plasma mutagenesis.Then, nine variables were screened using Plackett-Burman experimental design, in which soluble starch, peptone and Tween 80 showed significantly affected tacrolimus production. Further studies were carried out employing central composite design to elucidate the mutual interaction between the variables and to work out optimal fermentation medium composition for tacrolimus production. The optimum fermentation medium was found to contain 61.61g/L of soluble starch, 20.61g/L of peptone and 30.79g/L of Tween 80. In the optimized medium, the production of tacrolimus reached 1293mg/L in shake-flask culture, and reached 1522mg/L while the scaled-up fermentation was conducted in a 1000 L fermenter, which was about 3.7 times higher than that in the original medium. Combining compound mutation with rational medium optimization is an effective approach for improving tacrolimus production, and the optimized fermentation medium could be efficiently used for industrial production.

Optimization of fermentation conditions is important in the development of bioprocesses. Here, we used the Taguchi experimental design and Response Surface Methodology to optimize fermentation medium for enhancing carboxymethyl cellulase (CMCase) production by marine actinomycetes Streptomyces sp. Bse 7-9. Optimization using the Taguchi experimental design we found that bagasse has a significant effect on other factors. The Central Composite Design was used to determine the interaction between the factors selected in the fermentation medium to obtain the optimal concentration of ingredients. The experimental results demonstrated that bagasse as a carbon source plays as the key component for the production of CMCase by marine actinomycetes Streptomyces sp. Bse 7-9. In conclusion, the optimal fermentation medium for maximum cellulase production by marine actinomycete Streptomyces sp. Bse 7-9 was as follows: bagasse concentration (1.84 % w/v), yeast extract (0.5 % w/v) and CaSO4 (0.02 % w/v). The maximum activity of CMCase at this optimum medium was 4.496 U mL−1.

To enhance the ribonucleic acid (RNA) productivity for industrial applications, this study employed strain screening and medium optimization to improve the content of RNA in Cyberlindnera jadinii. A rapid screening method, combining atmospheric and room temperature plasma mutagenesis, 48-deep-well plates fermentation, and microplate reader detection, was developed. A mutant strain named WB15 with high RNA content was successfully obtained, exhibiting the RNA content of 156 ± 4.5 mg/g DCW, 1.4 times of the starting strain CCTCC AY 92020. Furthermore, Plackett–Burman design and response surface methodology were employed to identify three significant factors (yeast extract, soybean peptone, and KH2PO4) affecting the RNA content. By utilizing the optimal medium composed of 13.43 g/L yeast extract, 12.12 g/L soybean peptone and 2.78 g/L KH2PO4, the RNA content of WB15 further increased to 184 ± 4.9 mg/g DCW. Additionally, the mutant strain WB15 exhibited a greater cellular width compared to AY 92020, along with increased growth rate and single-cell RNA content by 22% and 48.9%, respectively. Perturbations in ribosome assembly, specifically a reduction in the ratio of ribosomal proteins to ribosomal RNA of the large subunit, might indirectly contribute to the higher RNA content in the WB15 strain. Overall, the combination of rapid screening with fermentation medium optimization proved to be an effective approach for improving the RNA content of C. jadinii, thus facilitating the industrial production of RNA.

In this paper, response surface methodology was applied to optimize the fermentation medium for epothilones high-producing strain. Considering the activity of epothilones, desirability function was employed to establish the criterion for the optimization. Suitable carbon sources and nitrogen sources were chosen by single-factor test firstly. Plackett-Burman design combined with the linear model was applied to identify the significant components in the fermentation medium. Based on the results of the Plackett-Burman design, a Box-Behnken design was developed for further optimization. A multivariate quadratic regression model was employed to fit the data of the Box-Behnken design and search for the optimum fermentation medium which was as follows (gi¤L-1): ammonium acetate 9.00, yeast extraction powder 7.00, sodium carboxymethyl cellulose 0.31, beef extract 4.00, NaCl 4.00, K2HPO4i¤3H2O 0.40, MgSO4i¤7H2O 0.20, CaCl2 0.09, FeCl3 0.01. The expected desirability values (Dv) with the optimum fermentation medium was 1.892. Five validation experiments were implemented with the optimum fermentation medium and their average Dv was 1.865. The relative error between the experimental values and the expected value was 1.14%, which indicated that the expected value fits experimental values.

Energetic Bacillus subtilis was preliminarily isolated from feather meal selection medium experiment, which could be used to produce Keratinase. Through using the ultraviolet ray produced by ultraviolet light and the compound mutation of sodium nitrite solution, a mutated strain was produced which can yield Kerati-nase with a high activity. The activity of Keratinase was 75.9% higher than that before the compound mutation. This was achieved by optimizing the fermentation medium of mutated strain. The optimum fermentation medium had the parameters as feather meal 5.5%, maize silage 0.8%, K+ 0.018 mol/L, Mg2+ 0.065 mol/L, Ca2+ 0.072 mol/L, Fe2+ 0.010 mol/L, and Na+ 0.088 mol/L. Based on the optimized fermentation medium, the highest yielding rate for producing enzyme was 1.117 U/mL, 25.22% higher than that before the optimization. The amino acid in the fermentation medium fluid reached 22.66 mg/mL. This paper presents a simple, and low cost way to produce high quality bio-fermentation feather meal.

This paper presented a method to separate Bacillus subtilis from natural environment, which could be used to produce keratinase. Through the use of ultraviolet ray and sodium nitrite compound mutation, a mutation strain FUN30.2 was produced that is capable to yield high vitality of keratinase. The vitality of keratinase was 75.9% higher than that before the mutation. This was achieved by optimizing the fermentation medium of FUN30.2. The optimum fermentation medium had the following components: 5.5% of feather meal, 0.8% of maize silage 0.018 mol/L of K+ concentration, 0.065 mol/L of Mg2+ concentration, 0.072 mol/L of Ca2+ concentration, 0.010 mol/L of Fe2+ concentration, and 0.088 mol/L of Na+ concentration. On the optimized fermentation medium, the highest yielding rate for producing enzyme by the strain was 1.117 U/mL, 25.67% higher than that before the optimization. The amino acid concentration in the fermentation medium fluid reached 22.66 mg/mL. The method provided in this paper was simple, and low cost. Therefore, it could be used in industrial production of good bacteria and ratio of fermentation medium components for bio-fermentation of feather meal.