Partial characterization of alfa-L-rhamnosidase produced by psychrotolerant Brevundimonas sp. Ci19 strain with potencial application to fruit juice debbitering

ALVARENGA A. E; FITZSIMONS R; ABATE C.M; CASTRO, G.R.

Conferencia; The 5th International Conference on Industrial Bioprocesses IFIB-2012; 2012

Pychrotolerant Brevundimonas sp. Ci19 was isolated from the Beagle Channel (latitude 54.8833, longitude: 68.1667) in the extreme South of Argentina, close to Antarctica. The Brevundimonas sp. Ci19 strain was selected based on the glycosil-hydrolase activities able to release both rhamnose and prunine from naringin, and glucose and naringenin from prunin. The α-L-rhamnosidase and ß-D-glucosidase activities were detected in a microbial culture containing rhamnose as a sole carbon source.The aim of the present work was to characterize and partially purify glycosil-hydrolase activities in Brevundimonas sp. Ci19 for potential use at industrial level.Intracellular extracts were parcially purified by ultrafiltration and gel-filtration chromatography with an 27-fold purification. Optimal pH and temperature were 6.80 and 30 ºC respectively for α-L-rhamnosidase, and 8.00 and 30 ºC respectively for ß-D-glucosidase. The α-L-rhamnosidase activity was enhanced by Ca2+ ions and inhibited by citric acid, glucose and Mg2+ and Zn2+ ions. Both enzymes were stable at 4°C at least for 72 h, whereas at 20°C the enzymes showed 40% inactivation after 48 h incubation. Considering that naringin and hesperidin glycoside flavonoids are the responsible compounds for the bitter taste of citric juices, and also the economic relevance of 41% of lemon production in the world and 88% of the industrialized lemon in the southern hemisphere is processed in Argentina. The promissory characteristics displayed by Brevundimonas sp. Ci19 enzymes are suggesting its potential application as debbitering agents at low temperature in food processing procedures in our country.