STUDY OF THE PROTEOLYTIC POOL PRODUCED BY ASPERGILLUS SOJAE IN SUBMERGED CULTURES WITH ORANGE PEEL

DANTE FRATEBIANCHI DE LA PARRA; JUAN MANUEL CRESPO, TATIANA ARTURI, CAROLINA VITA, SEBASTIÁN CAVALITTO; CANAN TARI

KUSADASI

Congreso; INTERNATIONAL FOOD CONGRESS NOVEL APPROACHES IN FOOD INDUSTRY NAFI 2014; 2014

EGE INIVERSITY ENGINEERING FACULTY FOOD ENGINEERING DEPARTMENT

Pectinases include a number of related enzymes involved in the degradation of pectic substances. These enzymes are widely used for many purposes, such as fruit juice extraction and clarification, and wine clarification. In this study, a screening of different pectolytic activities in a crude extract from submerged cultures of the filamentous fungi Aspergillus sojae was performed, using orange peel as the sole carbon source of the cultures. Assays were performed by duplicate in 1000 ml Erlenmeyer flasks with 200 ml medium containing orange peel (40 g/L) and ammonium sulfate (2.75 g/L); initial media?s pH was adjusted to 3.3. Cultures were inoculated with 1.4x105 spores/ml and incubated at 30ºC in an orbital shaker at 200 rpm. Spore suspensions used as inoculum were obtained from molasses agar slants using 0.02 % Tween-80 water. Samples were taken every 12 hours for up to 216 hours, filtered through cheese cloth and centrifuged at 4ºC and 6000 rpm for 20 min. Supernatant was used for different pectolytic activity measurements. Polygalacturonase, endo-pectinase, pectin-lyase and pectin-esterase activities were assayed. Pectin-esterase activity was detected from the 96 hours sample onwards. Polygalacturonase and endo-pectinase activity were detected from the 36 hours sample onwards, both reaching a plateau of maximum activity/ml culture between 156 and 168 hours. These results together with the fact that no pectin-lyase activity could be detected along the cultures suggest that endo-pectinase and polygalacturonase activities might correspond to a single polygalacturonase with an endo action pattern, although further studies should be performed for confirmation