Evaluation of agro-industrial wastes for polygalacturonase production

EVCAN, EZGI; GOGUS, NIHAN; TARI, CANAN; CAVALITTO, SEBASTIÁN FERNANDO

Chicago

Congreso; 2013 IFT Annual Meeting & Food Expo; 2013

IFT

Food industry forms a large quantity of wastes, where their accumulations are of primary environmental concern. Apple pomace (AP) among fruit pomaces makes up a good substrate because of its rich components such as pectin, carbohydrates, dietary fibres and minerals. Orange peel (OP) is another agro-industrial waste rich in pectin, cellulose and hemicelluloses, a necessary supplement for the production of induced enzymes like polygalacturonase (PG) which hydrolyses the pectic substances. PG finds wide industrial applications such as extraction, clarification and filtration of tea, juice and wine. Therefore, the goal of this study was to investigate the potential of important agro-industrial wastes; AP and OP as carbon sources, using an industrially important microorganism Aspergillus sojae, to maximize the PG production. Primarily, factors such as various hydrolysis forms of the C sources (hydrolyzed-AP, nonhydrolyzed-AP, hydrolyzed-AP+OP, nonhydrolyzed-AP+OP), N sources (ammonium sulphate, urea) and incubation time (4, 6, 8 days) were screened. It was observed that maximum PG activity was achieved at a combination of nonhydrolyzed-AP+OP and ammonium sulphate with 8 days of incubation. For optimization, ammonium sulphate concentration and the mixing ratios of AP+OP at different total C concentrations (9, 15, 21 g/l) were evaluated for maximum PG production. Consequently, it was determined that at maximum C concentration (21 g/l), OP could be used as the only C source in the presence of maximum concentration of ammonium sulphate (8 g/l) resulting in the highest PG activity (143.394 U/ml). On the other hand at 15 g/l total C concentration, 1:1 mixing ratio of OP+AP resulted into a considerable PG activity (120.904 U/ml) as well. These results demonstrated that AP can be evaluated as an additional C source to OP for PG production, which in turn both can be alternative solutions for the elimination of the waste accumulation in the food industry with economical returns.