Optimization of Conditions for cellulase Secretion for Some soil Fungi in Vitro

Abstract

This study aimed to determine optimization of conditions for enzyme secretion from many soil isolated fungi, the fungal species was cultivated on CMC agar plates for 5 days, to test its cellulolytic ability. The inhibition Zone 5.1, 5 , 5 cm of A.oryzae , A.niger and A. terreus. while when using Mandels-Weber medium , the activity of enzyme increased to 6.61, 4.14 and 5.61) U/ ml respectively when using Corn cobs , Results showed that ,the best chemical pretreatment when using NaOH at 100C0 in 30min on Corn cobs .The total cellulase are reached to 1.63 , 1 and 1.21 U / ml when using A. oryzae, A.niger and A. terreus respectively to degrade after treatment , and Three fungal species were inoculated into Mandels-Weber medium and incubated at 30 C◦ for a period of 168 hours . The cellulase activity was measured at regular intervals. However, the Incubation time are similar all the fungi at 96 hours the maximum yield of activity were 2 , 1.62 and 1.79 U / ml respectively by A. oryzae, A.niger and A. terreus , and Production Fpase ,CMCase , ß-glucosidases at different temperatures on the production of cellulolytic enzymes was examined of culture media , the highest activity recorded 1.64, 1.41 and 1.49 U/ml , 1.61 , 1.43 and 1.51 U/ml and 30.86 , 25.76 and 28.44 U/ml respectively at 30C° when using Corn cobs as carbon source . The optimized media were prepared and determine the pH was set at different levels 4, 5, 6, 8 and 10; the three different cellulolytic enzyme activities were detected separately for different fungi at an initial pH 6. Results revealed that the concentration of substrate (Corn cobs) for enzymes in different fungi during fermentation as carbon source was 6%, The tested fungi were able to produce maximum activities of the enzymes ,its 2.28 , 2.25 and 2.40 U/ml for Fpase and 2.48 , 2.28 and 2.39 ) U/ml for CMCase were ( 42.34 , 36.65 and 39.87 ) U/ml for ß-glucosidases . Finally, the nitrogen sources studied (KNO3 , (NH4)2SO4) in concentration ( 2, 4 , 6 ) % gave the highest production of all three main components of cellulase by fungi . The activity at concentration 6 % gave the highest activity for all fungi 1.92 , 1.51 and 1.80 U/ml and 1.89 , 1.63 and 1.72 U/ml respectively when using KNO3 and (NH4)2SO4 on Fpase . while, CMCase gave the highest activity in same nitrogen source were 2, 1.59 and 1.72 U/ml and 2.60 , 2.11 , 2.23 U/ml respectively when using nitrogen sources and ß-glucosidase gave activity 43.54 , 35.49 , 38.61 U/ml and 50, 39.28, 42.59 U/ml in same nitrogen source and concentration .On the other hand , The maximum activities of FPase, CMCase and β-glucosidase obtained followed by NH4NO3 and (NH4)2PO4 gave little activities compared with nitrogen source .