title: Evaluation of agro-industrial wastes, their state, and mixing ratio for maximum polygalacturonase and biomass production in submerged fermentation.
abstract: The potential of important agro-industrial wastes, apple pomace (AP) and orange peel (OP) as C sources, was investigated in the maximization of polygalacturonase (PG), an industrially significant enzyme, using an industrially important microorganism Aspergillus sojae. Factors such as various hydrolysis forms of the C sources (hydrolysed-AP, non-hydrolysed-AP, hydrolysed-AP + OP, non-hydrolysed-AP + OP) and N sources (ammonium sulphate and urea), and incubation time (4, 6, and 8 days) were screened. It was observed that maximum PG activity was achieved at a combination of non-hydrolysed-AP + OP and ammonium sulphate with eight days of incubation. For the pre-optimization study, ammonium sulphate concentration and the mixing ratios of AP + OP at different total C concentrations (9, 15, 21 g l(-1)) were evaluated. The optimum conditions for the maximum PG production (144.96 U ml(-1)) was found as 21 g l(-1) total carbohydrate concentration totally coming from OP at 15 g l(-1) ammonium sulphate concentration. On the other hand, 3:1 mixing ratio of OP + AP at 11.50 g l(-1) ammonium sulphate concentration also resulted in a considerable PG activity (115.73 U ml(-1)). 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.
authors.affiliation: a Department of Food Engineering , Izmir Institute of Technology , Gulbahce Campus, TR 35430 , Urla , Izmir , Turkey.
authors.forename: Nihan
authors.initials: N
authors.lastname: Göğüş
authors.forename: Ezgi
authors.initials: E
authors.lastname: Evcan
authors.forename: Canan
authors.initials: C
authors.lastname: Tarı
authors.forename: Sebastián F
authors.initials: SF
authors.lastname: Cavalitto
mesh_terms: D000645:Ammonium Sulfate; D001230:Aspergillus; D018533:Biomass; D032084:Citrus sinensis; D005285:Fermentation; D007220:Industrial Waste; D027845:Malus; D011096:Polygalacturonase / Q000032:analysis / Q000378:metabolism*; D015203:Reproducibility of Results; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D007220:Industrial Waste; D011096:Polygalacturonase; D000645:Ammonium Sulfate
keywords: Aspergillus sojae; agro-industrial waste; apple pomace; orange peel; polygalacturonase