title: Preservation of Bacillus firmus strain 37 and optimization of cyclodextrin biosynthesis by cells immobilized on loofa sponge.
abstract: 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.
authors.affiliation: Department of Pharmacy, State University of Maringá-UEM, Av. Colombo 5790, Maringá-PR 87020-900, Brazil.
authors.forename: Rúbia
authors.initials: R
authors.lastname: Pazzetto
authors.forename: Sabrina Barbosa de Souza
authors.initials: SB
authors.lastname: Ferreira
authors.forename: Elder James Silva
authors.initials: EJ
authors.lastname: Santos
authors.forename: Cristiane
authors.initials: C
authors.lastname: Moriwaki
authors.forename: Teresinha Aparecida
authors.initials: TA
authors.lastname: Guedes
authors.forename: Graciette
authors.initials: G
authors.lastname: Matioli
mesh_terms: D001407:Bacillus / Q000166:cytology / Q000378:metabolism*; D001422:Bacterial Adhesion; D018914:Cells, Immobilized; D003196:Computer Graphics; D003912:Dextrins / Q000737:chemistry; D005612:Freeze Drying; D005638:Fruit / Q000737:chemistry* / Q000382:microbiology; D006863:Hydrogen-Ion Concentration; D029776:Luffa / Q000737:chemistry* / Q000382:microbiology; D050296:Microbial Viability; D008954:Models, Biological; D011309:Preservation, Biological; D047392:beta-Cyclodextrins / Q000378:metabolism*
chemical_list: D003912:Dextrins; D047392:beta-Cyclodextrins