Isolation and identification of protease- producing halophilic bacteria in traditional Jinzhou shrimp paste

Objective: To isolate and identify protease- producing halophilic bacteria from the fermentation prophase of traditional Jinzhou shrimp paste. Methods: Protease- producing halophilic bacteria were isolated by 1.0%skimmed milk Gibbons test.These strains were identified by morphology,biochemical characteristics and molecular biology.Total soluble protein was analyzed using SDS- PAGE test.Results: 16 strains protease- producing halophilic bacteria were obtained.Strain CW0- 1,CW0- 2,CW0- 3 and CW0- 4 were identified as Vibro sp.,strain CW1- 1,CW2-1 and CW2-2 were identified as Staphylococcus nepalensis,strain CW2-3,CW5-1,CW5-2 and CW5-3 were identified as Staphylococcus equorum,strain CW3-1,CW3-2,CW4-1 and CW4-2 were identified as Virgibacillus sp.,strain CW4-3 was identified as Virgibacillus dokdonensis.The Vibro sp.mainly existed in raw shrimp,halophilic Staphylococcus sp.were observed in fermentation second month and fifth month,Virgibacillus sp.were observed in fermentation third month to fourth month.Staphylococcus sp.and Virgibacillus sp.presented alternate successions,which were the dominant protease- producing halophilic bacteria in the fermentation prophase of shrimp paste.Total soluble protein was gradually decreased with the extension of fermentation time.Conclusion: Staphylococcus sp. and Virgibacillus sp.were the dominant protease- producing halophilic bacteria in the fermentation prophase of shrimp paste,and were considered as the dominant bacteria of degradation protein.