Screening of pectinolytic activities of various strains belong to Aspergillus niger group and studies through on the enhancenment of activity

In this study pectinolytic activities of 262 mold strains which were isolated fromvineyards from Manisa region belong to 11 taxa included in Aspergillus niger group werescreened and all the studied strains have been found that have ability to produce pectinolyticactivity. Enzymatic index of the strains according to colony diameter and hydrolysis zone weredetermined and they were grouped. All the strains were divided into three enzymatic indexgroups as 1-2, 2-3 and ›3. Distribution of the strains according to these groups are as followed:88,5 % (233 strains), 9,9 % (26 strains), 1,6 % (3 strains), respectively.After determination of three different enzymatic index and different colony diameters forstrains, in order to find out a relation among these differences and enzymatic activitiespolygalacturonase (PG) and polymethylgalacturonase (PMG) activities were investigated bysubmerged and solid state fermentation methods using 12 strains from six taxa. To the resultsof submerged fermentation in which pectin 1,5 % from apple was used as sole carbon andenergy source highest PG activities were obtained from the strains of A. foetidus var. pallidus-1Ege-K-730 and Ege-K-635 as 91,7 and 86 U 50mL , respectively. Highest PMG activity on-1submerged fermentation was obtained from A. aculeatus Ege-K-398 as 19,2 U 50mL . Basedon the results of solid state fermentation which only wheat bran used as substrate highest PG1activities were obtained from A. foetidus var. pallidus Ege- K-730 as 39 Ug- and A. foetidus var.-1pallidus Ege-K-635 as 38 Ug . According to these results, it was observed on solid stateconditions activities were rised up almost 20 times for PG as compared to submergedfermentation.Since the strain A. foetidus var. pallidus Ege-K-730 is the producer of Ochratoxin A,further improvement studies for enzyme production were proceeded with A. foetidus var.pallidus Ege K-635. In order to improve enzyme activities, effects of substrate type andcomposition, carbon-nitrogen rate, moisture level and inoculum amount were investigated.As a result the highest PG production from the strain A. foetidus var. pallidus Ege-K-635 on solid state fermentation the optimum conditions were determined for substrate7composition as wheat bran:sugar beet pulp in 1:2 ratio, inoculum amount as 2x10 spores-12,5gr , moisture level as 75 % and carbon-nitrogen ratio as 31:1. Under these conditions-1highest level for PG activity was measured as 385 Ug and an improvement about 10 times and200 times as compared to activities obtained from solid state fermentation with wheat bran andsubmerged fermentation with pectin were achieved, respectively.Key Words: Aspergillus niger group, polygalacturonase, polymethylgalacturonase, solid statefermentation, sugar beet pulp