title: Cyclodextrin glycosyltransferase production by free cells of Bacillus circulans DF 9R in batch fermentation and by immobilized cells in a semi-continuous process.
abstract: Cyclodextrin glycosyltransferase (CGTase) catalyzes starch conversion into cyclic or linear oligosaccharides, important industrial products for the complexation of non-polar substances. In this work, conditions to increase CGTase production from Bacillus circulans strain DF 9R were optimized by two systems. On one hand, free cells were grown in batch fermentation experiments to optimize aeration and pH. The highest activity (1.47 ± 0.21 U ml(-1)) was achieved after 48 h of growth, aeration of 1.5 vvm and pH regulated to 7.6. On the other hand, bacterial cells were immobilized on loofa and synthetic sponge, and used for CGTase production in a semi-continuous process. An initial biomass of 30 mg of lyophilized cells and an immobilization time of 24 h with loofa or synthetic sponge were enough to achieve increased production of CGTase: 0.91 ± 0.10 and 0.95 ± 0.11 U ml(-1), respectively. Sponges with immobilized bacteria were reused in 12 successive cycles. Besides, in our conditions, CGTase was not adsorbed onto the supports used for immobilization, which ensured the total recovery of the enzyme from the culture medium. The two CGTase production processes studied showed similar productivity and could be potentially scaled up.
authors.affiliation: Departamento de Ciencias Básicas, Universidad Nacional de Luján, Luján, 6700, Buenos Aires, Republic Argentina.
authors.forename: Hernán
authors.initials: H
authors.lastname: Costa
authors.forename: Jorgelina Rodríguez
authors.initials: JR
authors.lastname: Gastón
authors.forename: Julia
authors.initials: J
authors.lastname: Lara
authors.forename: Camila Ortiz
authors.initials: CO
authors.lastname: Martinez
authors.forename: Cristiane
authors.initials: C
authors.lastname: Moriwaki
authors.forename: Graciette
authors.initials: G
authors.lastname: Matioli
authors.forename: Susana Alicia
authors.initials: SA
authors.lastname: Ferrarotti
mesh_terms: D000818:Animals; D001407:Bacillus / Q000201:enzymology*; D018533:Biomass; D019149:Bioreactors; D005285:Fermentation; D005964:Glucosyltransferases / Q000096:biosynthesis*; D006863:Hydrogen-Ion Concentration; D011161:Porifera
chemical_list: D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase