Β-cyclodextrin Production Research Articles

Improved Production of Cyclodextrins by Alkalophilic Bacilli Immobilized on Synthetic or Loofa Sponges

This study aimed to improve the production of β-cyclodextrin (β-CD) by microbial cells immobilized on synthetic or loofa sponges both with and without the use of alginate or chitosan. The most suitable matrix for the immobilization of Bacillus firmus strain 7B was synthetic sponge and for Bacillus sphaericus strain 41 was loofa sponge. After 330 days of storage, the β-CD production by Bacillus firmus and Bacillus sphaericus remained at around 41% and 49%, respectively, of initial levels. After 24 days of immobilization on loofa sponge, Bacillus sphaericus strain 41 achieved an improved operational stability, reaching 86.6 mM β-CD after 20 days of production, compared to only 32.8 mM of β-CD produced by free Bacillus sphaericus strain 41 cells. The expected increase in β-CD production by immobilized cells of Bacillus firmus strain 7B on synthetic sponge for 4 days was not statistically different to that for cells immobilized for 24 days. The application of this process on an industrial scale using loofa sponge, an inexpensive and renewable matrix, will allow the stable production of β-CD.

Preservation of Bacillus firmus Strain 37 and Optimization of Cyclodextrin Biosynthesis by Cells Immobilized on Loofa Sponge

The preservation of Bacillus firmus strain 37 cells by lyophilization was evaluated and response surface methodology (RSM) was used to optimize the β-cyclodextrin (β-CD) production by cells immobilized on loofa sponge. Interactions were studied with the variables temperature, pH and dextrin concentration using a central composite design (CCD). Immobilization time influence on β-CD production was also investigated. B. firmus strain 37 cells remained viable after one year of storage, showing that the lyophilization is a suitable method for preservation of the microorganism. From the three-dimensional diagrams and contour plots, the best conditions for β-CD production were determined: temperature 60 °C, pH 8, and 18% dextrin. Considering that the amount of dextrin was high, a new assay was carried out, in which dextrin concentrations of 10, 15, and 18% were tested and the temperature of 60 °C and pH 8 were maintained. The results achieved showed very small differences and therefore, for economic reasons, the use of 10% dextrin is suggested. Increasing the immobilization time of cells immobilized on synthetic sponge the β-CD production decreased and did not change for cells immobilized on loofa sponge. The results of this research are important for microorganism preservation and essential in the optimization of the biosynthesis of CD.

Effect of substrate concentration and temperature on the kinetics and thermal stability of cyclodextrin glycosyltransferase for the production of β-cyclodextrin: Experimental results vs. mathematical model

A mathematical model for simultaneously studying the effect of substrate concentration and temperature on β-cyclodextrin ( β-CD) production by cyclodextrin glycosyltransferase (CGTase) was developed. The kinetic parameters, involved in a Michaelis–Menten model and thermal stability of CGTase, were determined. The kinetic parameters show that raising the temperature not only increased the reaction rate of the enzyme but also its affinity for the substrate. However, an increase in the temperature reduced the thermal stability of the enzyme. Therefore, the developed model that expresses both the reaction rate and the stability of the enzyme was used to determine the optimum temperature that provided a high reaction rate with good stability. The importance of developing the model is to demonstrate its successful application to practically determine the optimum condition that represents a compromise between a process with a high productivity and one with a high working efficiency.

Cyclodextrin production by Bacillus firmus strain 37 cells immobilized on loofa sponge

Loofa sponge, loofa sponge–chitosan, loofa sponge–alginate and synthetic sponge were tested as matrices for the immobilization of Bacillus firmus strain 37 cells for β-cyclodextrin (β-CD) production from dextrin. Similar results were obtained for the matrices studied and loofa sponge was chosen for further studies because of its renewable character and simple method of immobilization. Optimization of the initial biomass, immobilization time and number of loofa discs were carried out. The period of 1 day and the amount of 30 mg of lyophilized cells were sufficient for immobilization on three loofa sponge discs to produce 20.2 mM of β-CD. Operational stability was evaluated in four repetitive cycles of 5 days each and all the matrices studied showed better behavior than free cells. The loofa sponge–alginate matrix showed the best operational stability, mantaining in the second cycle the same β-CD production obtainded in the first cycle and 77% production in the third cycle, whereas the free cells were almost inactive in this cycle. The innovative use of loofa sponge, an environmentally friendly matrix, for β-CD production gave good performance at an affordable cost, thus making the process potentially suitable for industrial scale-up.

Kinetic characteristics of β-cyclodextrin production by cyclodextrin glycosyltransferase from newly isolated Bacillus sp. C26

The kinetic characteristics of β-cyclodextrin production by a cyclodextrin glycosyltransferase (CGTase) produced by Bacillus sp. C26, a new isolate from a soil sample was investigated. Considering highest yield and initial production rate of β-cyclodextrin, among the starches examined, soluble starch, tapioca starch, sago starch, corn starch and rice starch, tapioca starch was the best substrate for this CGTase. The optimum temperature for tapioca starch gelatinization prior to its use as a substrate for β-cyclodextrin production was 65oC. The yield and initial production rate of β-cyclodextrin increased with increasing starch concentration up to 6% and an enzyme concentration up to 48 U/g-starch. The kinetic parameters of V max and K m of β-cyclodextrin production from tapioca starch by CGTase were 1.59 mg/mL/h and 22.3 mg/mL, respectively. Considering high initial production rate and high yield of β-cyclodextrin, the optimum reaction temperature was at 50oC. This study provided the necessary kinetic information that may be useful to define the most suitable condition for industrialized production ofβ-cyclodextrin with the high yield and productivity.

Approaches for yield increase of β-cyclodextrin formed by cyclodextrin glucanotransferase from Bacillus megaterium

Two methods for increasing β-cyclodextrin yield, achieved with cyclodextrin glucanotransferase from Bacillus megaterium were investigated. A membrane process was performed, allowing a reuse of the enzyme. A process for simultaneous production and isolation of β-cyclodextrin in the presence of complexing agents was conducted. The β-cyclodextrin yield was increased twofold, when the product was precipitated with trichloroethylene or toluene. A change in the product selectivity of cyclodextrin glucanotransferase occurred, resulting in an increase in the relative amount of β-cyclodextrin up to 90% of all cyclodextrins formed. Yield increase was due to the removal of product inhibition and the coupling activity of the enzyme, which limited the full conversion of starch. The isolated cyclodextrin products contained 75–79% β-cyclodextrin, and 4–6% each of α-, and γ-cyclodextrins.

Cyclodextrin production by Bacillus firmus strain 37 immobilized on inorganic matrices and alginate gel

Production of β-cyclodextrin (β-CD) by Bacillus firmus strain 37 cells, immobilized by adsorption on silica–titania (SiO 2/TiO 2) and silica–manganese dioxide (SiO 2/MnO 2) matrices, was optimized for temperature, substrate concentration and initial biomass. The immobilization process was most efficient at 60 °C with 10% maltodextrin and 1.0 g of cells, resulting, after a 5-day assay, in a β-CD production of 11.7 ± 0.1 mM for cells immobilized on SiO 2/TiO 2 and 11.2 ± 0.1 mM in SiO 2/MnO 2. Entrapment in alginate gel resulted in a maximum β-CD production of 4.1 ± 0.1 mM, which was maintained constantly until the end of a 10-day assay. During this same period, free cells produced 8.3 ± 0.2 mM, and cells immobilized on SiO 2/TiO 2 and SiO 2/MnO 2, 16.7 ± 0.4 and 17.3 ± 0.5 mM, respectively. β-CD production by cells immobilized in calcium alginate in four repetitive cycles of 5 days each, showed an increase up to the third cycle, reaching 4.8 ± 0.2 mM, while production by free cells started falling from the second cycle. In this same assay, cells immobilized on SiO 2/TiO 2 and SiO 2/MnO 2, showed the best β-CD production results at the end of the first cycle, with a gradual fall occurring due to the desorption of cells thereafter.

Experimental design to optimization of beta cyclodextrin production from ungelatinized sago starch

The aim of this study is to produce beta cyclodextrin (β-CD) from ungelatinized, but annealed (65 °C) sago starch using cyclodextrin glucosyltransferase (CGTase). The optimization processes were conducted at three stages using Response Surface Methodology. Preliminary data have shown that the three (3) highest points for each of the studied parameters were pH, concentration of sago starch and enzyme, and also agitation. In the second stage, two level full factorial design (2n FFD) was applied to determine the significant parameters affecting the production of β-cyclodextrin. Statistical analyses showed that pH, enzyme and sago starch concentration were the significant parameters. The final stage of optimization involved the use of Central Composite Design to determine and predict the optimum yield of β-cyclodextrin. The optimum condition for production cyclodextrin was at pH 8.62 (Glycine–NaOH buffer 0.05 M), 0.65% v/v sago starch and 15% w/v enzyme concentration, where 8.43 g β-cyclodextrin/L was produced after 4 h of reaction.

Production of β-cyclodextrin: Effect of pH, time and additives

In the present paper attempt was made to produce an excipient, β-cyclodextrin from starch by the action of an enzyme cyclodextrin glucosyl transferase. The microbial strain utilized was Bacillus circulans because of its specificity for production of β-cyclodextrin. First the culture was grown under controlled conditions to obtain an enzyme cyclodextrin glucosyl transferase which was isolated and purified. The crude enzyme was employed for bioconversion of starch to β-cyclodextrin. Some parameters like incubation pH, incubation and fermentation time and effect of certain additives like polyethylene glycol and calcium chloride added during incubation were studied to optimize its yield. The maximum yield of cyclodextrin glucosyl transferase was after 36 h of fermentation. β-cyclodextrin yield was found to increase with the increase in incubation period, by the addition of polyethylene glycol 200, polyethylene glycol 400 and at pH 6. The activity and stability of enzyme was found to increase by addition of calcium chloride.

A novel process of cyclodextrin production by the use of specific adsorbents: Part I. Screening of specific adsorbents

Novel adsorbents that are composed of ligand, spacer and support were chemically synthesized and the two consecutive screenings of them made it possible to determine the adsorbents that were most recommendable for α- and β-cyclodextrin (CD) production. First, ligands of high adsorption selectivity for each CD were screened from among the candidates (carboxylic acids) that are tied in ionic bonds to two types of strongly basic anion exchange resins as support. Secondly, ligand derivatives (as ligand and spacer) were bound in covalent bonds onto chilosan beads as support and then, the most suitable spacer length for the CDs' adsorption selectivity and capacity were investigated. An optimal mol ratio of ligand to amino group of the beads was also examined. Stearic acid was the most effective ligand for α-CD, whereas cyclohexanepropanamide- n-caproic acid was the best for β-CD. Adsorption selectivity of adsorbents derived from carboxylic acids (stearic and/or palmitic) and chitosan beads was almost 100%, while their adsorption capacities were large enough to meet the demand for economic production and purification of CDs on an industrial scale.

Production of Maltosyl β-Cyclodextrin by a Bioreactor System with Pullulanase Immobilized on Partially Deacetylated Chitin

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