abstract
N-Acetyl-glucosaminidases (GlcNAcases) are exoenzymes found in a wide range of living organisms, which have gained great attention in the treatment of disorders related to diabetes, Alzheimer's, Tay-Sachs', and Sandhoff's diseases; the control of phytopathogens; and the synthesis of bioactive GlcNAc- containing products. Aiming at future industrial applications, in this study, GlcNAcase production by marine Aeromonas caviae CHZ306 was enhanced first in shake flasks in terms of medium composition and then in bench-scale stirred-tank bioreactor in terms of physicochemical conditions. Stoichiometric balance between the bioavailability of carbon and nitrogen in the formulated culture medium, as well as the use of additional carbon and nitrogen sources, played a central role in improving the bioprocess, considerably increasing the enzyme productivity. The optimal cultivation medium was composed of colloidal a-chitin, corn steep liquor, peptone A, and mineral salts, in a 5.2 C:N ratio. Optimization of pH, temperature, colloidal alpha-chitin concentration, and kappa(L) a conditions further increased GlcNAcase productivity. Under optimized conditions in bioreactor (i.e., 34 degrees C, pH 8 and kappa(L)a 55.2 h(-1)), GlcNAcase activity achieved 173.4 U.L-1 after 12 h of cultivation, and productivity no less than 14.45 U.L-1.h(-1) corresponding to a 370-fold enhancement compared to basal conditions.
keywords
ELEMENTAL COMPOSITION C; CHITINASE PRODUCTION; BACILLUS-THURINGIENSIS; OPTIMIZATION; GROWTH; SUBSTRATE; LICHENIFORMIS; CULTIVATION; BACTERIA; ENZYMES
subject category
Microbiology
authors
Cardozo, FA; Feitosa, V; Mendonça, CMN; da Silva, FVS; Converti, A; Oliveira, RPD; Pessoa, A
Groups
acknowledgements
This work was supported by the Sao Paulo Research Foundation (FAPESP), Brazil, [grant numbers 2012/16824-0 and 2013/18773-6].