Bovine Bone Charcoal as Support Material for Immobilization of <em>Bacillus firmus</em> Strain 37 and Production of Cyclomaltodextrin Glucanotransferase by Batch Fermentation in a Fluidized Bed

Abstract

The process described in the present work uses air supplementation in a fluidized bed reactor containing Bacillus firmus strain 37 immobilized on active bovine bone charcoal, to produce by batch fermentation the enzyme CGTase (cyclomaltodextrin-glucanotransferase). Three different aeration rates were evaluated. The maximum CGTase activity was achieved after 120 hours of fermentation with aeration rate of 2 vvm and was equal to 2.48 U/mL. When 0.5 and 1 vvm were used the enzymatic activities achieved 1.1 and 0.57 U/mL, respectively. Bovine bone charcoal was characterized in terms of surface area, pore size and volume. To the best of our knowledge, the immobilization of microorganism cells in bovine bone charcoal for CGTase production has not been reported in the literature. Our results showed that fluidized bed reactor allows retaining high concentration of biomass, improving biomass-substrate contact and operation at low residence times, which resulted in improved enzyme production. Therefore, the process as proposed has great potential for industrial development.

Cell Immobilization for Cyclodextrin Production: Mini Review

“…To date, there is no specific report on the immobilization of cells via mechanical containment behind a barrier for CD production, although there is one for CGTase production. Silva et al [47] studied the immobilization of Bacillus firmus strain 37 on bovine bone charcoal for the production of CGTase. Bovine bone charcoal was used as the support material because it has hydroxyapatite (calcium phosphate) and traces of calcium carbonate, which makes it an alkaline buffer [48].…”

Batch CGTase Production with Free and Immobilized <i>Bacillus firmus</i> Strain 37 in Bovine Bone Charcoal

“…The characterization of bovine bone charcoal, such as the physicochemical properties, was carried out by isotherms adsorption of N2 to estimate specific area through B.E.T. (Brunauer-Emmett-Teller) model and the results can be consulted in our published paper in 2018 [26].…”

“…The interaction between the charcoal and immobilized microorganisms was studied in our article published in 2018 [26], in which it was possible to observe by SEM microscopy (Scanning electron microscopy) the adhered rod-shaped microorganisms, probably Bacillus firmus, in the activated bone charcoal, proving the success of cell immobilization. Immobilized cell fermentation was carried in order to determine the enzyme activity profile during time.…”