الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Fifty bacterial isolates were screened for their pectinolytic activity, one isolate was selected out of nine isolates as the most potent, the selected isolate was confirmed for the identification based on alignment of 16s rRNA gene sequence available in gene bank. Basic local alignment search tool (BLAST) search indicated that the selected isolate named as Bacillus subtilis RA7 showed 100% identity to Bacillus subtilis FZB42 strain (accession number: 00925.1). The maximum pectinase productivity was achieved after 2 days, at 35C, pH 8 under shaking and by 1% pectin as carbon source and 0.47% ammonium sulphate as nitrogen source. Purification of pectinase takes place by 83% ethanol and sephadex G100 which increased the purity by 4 fold after gel filteration. Pure exopolygalacturonase had molecular weight of 40 kDa by SDS PAGE, with high alanine content. Maximal activity of pure exo-polygalacturonase was attained at pH 9, 45C with concentration of pectin 2.0%: Ca2+ exerted the activity of purified enzyme was significantly suppressed in presence of Cu2+, Mn2+, Fe2+, Co2+, Ba2+ and EDTA. With respect to the commercial application of pectinase certain trials were achieved on some fruits pulp (mango, orange, peach, apple) which treat with purified exopolygalacturonase of Bacillus subtilis RA7, it was found that the ability of the enzyme under study in reduction of the viscosity of the fruit under test, pulps which reached 63.11%, 59.30%, 45.07% and 57.7%, respectively, if compared with untreated one. Decreasing in dry weight of fruit residue with percentage reached 58.4%, 48.8%, 27.8% and 37.9% respectively if compared with untreated one. The clearance of obtaining juice reached to 52.63%, 43.85%, 38.46% and 43.64% in case of treated mango, orange, peach and apple respectively with respect of untreated fruits. Generally it is clear that exo-polygalacturonase from Bacillus subtilis RA7 is commercially favored in juice extraction & clarification, and processing for increasing yield and decreasing wastes.