الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
 |  | from | 223 |  |  |
| | | from | 223 | | |
Abstract
The optimal period for production of β-glucanase from Penicillium chrysogenum was 5th day. The optimal pH and temperature for the enzyme production were 5.5 and 30oC, respectively. The best agitation speed was 150 rpm. • The best carbon source for production of the enzyme from P. chrysogenum was CMC at 2% concentration. The best nitrogen source was ammonium nitrate at 1% concentration. • β-glucanase from P. chrysogenum was purified using 85% (NH4)2SO4 precipitation, DEAE-cellulose and Sephadex G200 with final specific activity of 210 Umg-1 protein and 15-fold. • The optimal enzyme pH and temperature for enzyme catalysis were 5 and 45oC, respectively. The optimal incubation time for enzyme catalysis was 40 min and the optimal substrate concentration was 10% w/v. • The Vmax was 32.79 Umg-1 protein whereas Km was 1.17% w/v. • T0.5 of β-glucanase was 45 min at 70oC. However, the T0.5 values in presence of glycol chitosan, trehalose, glycerol and mannitol were 85, 90, 102.3 and 104.7 min, respectively. • The two amino acids cysteine and alanine activated β-glucanase whereas leucine, histidine and arginine inhibited the enzyme activity. • The two cations Ca2+ and Mn2+ were activators whereas Cu2+, Pb2+, Zn2+, Hg2+ and Ag2+ were inhibitors. • The three adenosine compounds AMP, ADP and ATP were activators for the enzyme particularly ATP which was more effective.Treatment of β-glucanase with Tween-80 resulted in the increasing of enzyme activity at the lower concentrations whereas the higher concentrations reduced the activity. • H2O2 inhibited the enzyme at all the tested concentrations. • The enzyme was inhibited by succinic anhydride, malic anhydride, acetic anhydride and citraconic anhydride with IC50 values of 8.6, 7.6, 7.4 and 7.7 mM, respectively. • The enzyme was modified by N-ethylmaleimide, phenylglyoxal, Nbromosuccinimide, dansyl chloride and diethyl pyrocarbonate. The IC50 values for the five compounds were 7.6, 6.5, 4.8, 5.2 and 7.8 mM, respectively. • The enzyme was activated by kinetin, gibberellic acid (GA3) and jasmonic acid (JA). • The enzyme was inhibited by three metal cleating agents: ethylenediaminetetraacetate (EDTA), α-α-dipyridyl and ophenanthroline. The IC50 values for the three compounds were 5.1, 22.1 and 5.7 mM, respectively. • The two thiol compounds dithiothreitol (DTT) and thioglycolate activated the enzyme activity at the lower concentrations whereas the higher concentrations were inhibitors. • The enzyme was immobilized on Ca-alginate and chitosan. The chitosan was better bead than Ca-alginate. The optimal concentration of glutaraldehyde for immobilization was 16% v/v. • The optimal temperatures of the free, alginate-immobilized and chitosanimmobilized enzyme were 45, 50 and 55oC, respectively.