Production, partial purification and characterization of alpha-L-rhamnosidase from Penicillium ulaiense.

V.B. RAJAL; A.G. CID; G. ELLENRIEDER; C.M. CUEVAS

WORLD JOURNAL OF MICROBIOLOGY & BIOTECHNOLOGY

Año: 2008 vol. 25 p. 1025 - 1033

0959-3993

Penicillium ulaiense is a post-harvest pathogenic fungus that attacks citrus fruits. Theobjective of this work was to study this microorganism as an ¥á-L-rhamnosidase producer and tocharacterize it from P. ulaiense. The enzyme under study is used for different applications in food andbeverage industries. ¥á-L-Rhamnosidase was produced in a stirred-batch reactor using rhamnose as themain carbon source. The kinetic parameters for the growth of the fungi and for the enzyme productionwere calculated from the experimental values. A method for partial purification, including (NH4)2SO4precipitation, incubation at pH 12 and DEAE-Sepharose chromatography yielded an enzyme with verylow ©¬-glucosidase activity. The pH and temperature optima were 5.0 and 60¨¬C, respectively. TheMichaelis-Menten constants for the hydrolysis of p-nitrophenyl-¥á-L-rhamnoside were Vmax = 26¡¾4 IUml-1 and Km = 11¡¾2 mM. The enzyme showed good thermostability up to 60¨¬C and good operationalstability in white wine. Co+2 affected positively the activity; EDTA, Mn2+, Mg2+, dithiotreitol and Cu2+reduced the activity by different amounts, and Hg2+ completely inhibited the enzyme. The enzymeshowed more activity on p-nitrophenyl-¥á-L-rhamnoside than on naringin. According to these results,this enzyme has potential for use in the food and pharmacy industries since P. ulaiense does notproduce mycotoxins.