Isolation and identification of halophilic bacteria producing halotolerant protease

Abstract

Halotolerant proteases are known as one of the important groups of enzymes that have been used widely in various industries. However, high production cost of proteases in term of energy used for sterilization and high risk of microbial contamination during fermentation become the obstacles during upstream processing. Moreover, proteases that capable to withstand with harsh conditions of salinity, temperature and pH are required in industry. Therefore, this study presents newly isolated halophilic bacteria producing halotolerant proteases. Halophilic bacteria were isolated from fermented fish sauce. Screening of the bacteria producing halotolerant protease enzymes was carried out by using skim milk salt agar containing 10% NaCl at pH 7 and incubated under aerobic condition at 37oC for 2 days. The selected isolates were identified based on their morphology followed by 16S rDNA gene sequence analysis. 40 colonies of halophiles bacteria were isolated, however, only 20 of them showing proteolytic activity. All of 20 isolates are motile and gram positive bacteria. From 20 isolates, only 6 were chosen for further analysis. B7 showed the highest proteolytic activity compared with others. Results of 16S rDNA gene sequence analysis showed 98% homology to Bacillus amyloliquefaciens subsp. plantarum strain FZB42. Therefore, B7 is identified as Bacillus amyloliquefaciens strain B7.

Biofouling of FeNP-Coated SWRO Membranes with Bacteria Isolated after Pre-Treatment in the Sea of Cortez

“…The accelerated biofouling test showed that the bacteria can exhibit growth under conditions of very high salinity, in the range of 3%-8% salt concentration by weight (see Figure 8). This result suggests that the bacteria indeed exhibits sporulation, as endospore production allows the bacteria to survive in extreme environmental conditions [42,43]. In addition, the ability of Bacillus halotolerans MCC1 to biofoul RO membranes was also demonstrated in this test.…”

The complete mitochondrial genome of brown algae: Sargassum fusiforme (Harvey) Setchell

“…This seaweed's body is yellowish-brown in color, is succulent and is rich in nutrition. Besides, it is rich in polysaccharides, proteins, and microelements which are beneficial to human body (Ma et al 2004;Xie et al 2014;Samad et al 2017). Due to the promising medical and food therapeutic effects, S. fusiforme have attracted a great deal of attention from both pharmaceutical and food industries.…”

Isolasi dan Seleksi Bakteri Proteolitik Asal Limbah Cair Tahu Sebagai Dasar Penentuan Agen Pembuatan Biofertilizer

“…Sedangkan Wardani dan Nindita (2012) berhasil mendapatkan 30 bakteri proteolitik dengan aktivitas protease yang beragam. Oleh karena itu, substrat yang digunakan sebagai sampel dalam mengisolasi bakteri proteolitik dapat diperoleh dari berbagai tempat yang banyak mengandung protein seperti limbah cair tahu, rumah pemotongan hewan, tambak, dan tempat pembuangan susu rusak serta tanah gambut yang kaya akan bahan organik, pada produk fermentasi terutama yang berbahan dasar kedelai seperti oncom (Lestari et al 2018) dan produk fermentasi ikan (Samad et al 2017). Isolasi dilakukan dengan menggunakan medium yang mengandung kasein, Zona bening yang merupakan substrat yang baik untuk mengisolasi bakteri penghasil enzim protease dan menginduksi sintesis enzim protease alkalin (Ward, 1983).…”