Optimization of Chitinase Production by the Antarctic Bacterium Arthrobacter psychrochitiniphilus strain 492

Chitinase acts in the hydrolysis of the ß -1-4 bond of N-acetyl-D-glucosamine and used for different biotechnological applications. The aim was to optimize the production of cold- active extracellular chitinase from Arthrobacter psychrochitiniphilus strain 492 isolated from Antarctica. This isolate was recovered from biofilm soil collected during the expedition OPERANTAR XXXII (summer 2013/2014) in Half Moon Island after cultivation in R2A culture medium and incubation at 15°C. This strain was selected out of 560 bacteria isolated from diverse Antarctic samples for optimization of chitinase production, the effects of nutrient composition (chitin, peptone, extract yeast, K2HPO, KH2PO4, MgSO4.7H2O, NH4NO3, and NaCl) and physicochemical parameters (pH) were evaluated using Plackett and Burman (PB) method, followed by 25-1 fractional factorial design and finally a Central Composite Design (CCD 23). Chitinase activity was enhanced by the interaction between chitin (2.0-5.5%) and NH4NO3 (1.5–5.0 g/L). The optimization of culture conditions with the aid of mathematical modeling increased 7.8-fold the enzyme activity when the maximum activity of CCD 23 (222, 7 U/mL) was compared with that obtained with the culture medium without optimization (28, 8 U/mL). Statistical experimental design was an efficient tool in the optimization of chitinase production by the Antarctic A. psychrochitiniphilus 492 bacterium.