Cyclodextrin glycosyltransferase production by free cells of Bacillus circulans DF 9R in batch fermentation and by immobilized cells in a semi-continuous process

COSTA, HERNÁN; RODRIGUEZ GASTÓN, JORGELINA ANDREA; LARA, JULIA; MARTINEZ ORTIZ, CAMILA; MORIWAKI, CRISTIANE; MATIOLI, GRACIETTE; FERRAROTTI, SUSANA ALICIA

BIOPROCESS AND BIOSYSTEMS ENGINEERING

SPRINGER

Lugar: Berlin; Año: 2015

1615-7591

Cyclodextrin glycosyltransferase (CGTase)catalyzes starch conversion into cyclic or linear oligosaccharides,important industrial products for the complexationof non-polar substances. In this work, conditions toincrease CGTase production from Bacillus circulans strainDF 9R were optimized by two systems. On one hand, freecells were grown in batch fermentation experiments tooptimize 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 otherhand, bacterial cells were immobilized on loofa and syntheticsponge, and used for CGTase production in a semicontinuousprocess. An initial biomass of 30 mg oflyophilized cells and an immobilization time of 24 hwith loofa or synthetic sponge were enough to achieveincreased production of CGTase: 0.91 ± 0.10 and0.95 ± 0.11 U ml-1, respectively. Sponges with immobilizedbacteria were reused in 12 successive cycles. Besides,in our conditions, CGTase was not adsorbed onto thesupports used for immobilization, which ensured the totalrecovery of the enzyme from the culture medium. The twoCGTase production processes studied showed similarproductivity and could be potentially scaled up.