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| Screening and Enzymatic Property of Protease Producing Bacterial Strains from Octopus Octopus ocellatus |
| WANG Yu-rong,QU Tian-li,JIN Yu-lan |
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Abstract Ten bacterial strains were isolated from octopus Octopus ocellatus by casein medium ,in which 4 strains S-1 ,S-2 ,S-3 and S-8 showed high protease activity .The major physical and chemical characteristics of the proteinases were studied in this article .The protease activity of the fermentation liquid was found to be 1289 U/mL in S-1 ,937 U/mL in S-2 ,1222 U/mL in S-3 ,and 885 U/mL in S-8 . The maximal proteases activity was observed at temperature of 30 ℃ for the strains S-1 ,and S-3 ,and at 50 ℃ for the strains S-2 ,and S-8 ,with the optimum pH of 8 .5 in stain S-1 ,7 .0 in strain S-2 ,8 .0 in S-3 ,and 7 .0 in S-8 .The SDS-PAGE ,substrate casein and active staining confirmed that the main proteases produced by strain S-1 had molecular weights of 149 .6 ,127 .4 and 40 .3 ku ,and the protease molecular mass in strain S-3 showed molecular weights of about 123 .3 ,112 .2 ,71 .6 and 37 .8 ku .The findings suggest that the protease from protease-producing bacterial strains in the octopus was feasible to be isolated due to suitable fermentation condition ,high activity and stability and can be applied to industrial production .
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Received: 25 April 2014
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