ISSN 2756-3391
African Journal of Parasitology Research ISSN 2756-3391 Vol. 7 (3), pp. 001-008, March, 2020. © International Scholars Journals
Full Length Research Paper
Characterization of Virgibacillus strain TKNR13-3 from fermented shrimp paste (ka-pi) and its protease production
Somboon Tanasupawat1*, Thanapun Taprig2, Ancharida Akaracharanya2 and Wonnop Visessanguan3
1Department of Biochemistry and Microbiology, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand.
2Department of Microbiology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
3National Center for Genetic Engineering and Biotechnology, Klong Luang, Pathumthani 12120, Thailand.
Accepted 05 January, 2020
Abstract
A moderately halophilic bacterium, TKNR13-3, isolated from fermented shrimp paste (ka-pi) in Thailand was identified as Virgibacillus halodenitrificans based on its phenotypic and chemotaxonomic characteristics, 16S ribosomal ribonucleic acid (Rrna) gene sequence and deoxyribonucleic-deoxyribonucleic (DNA-DNA) relatedness. The strain TKNR13-3 produced substantial amount of extracellular protease. Its protease production was maximum when grown in JCM No.377 medium without casamino acids but containing 2% (w/v) yeast extract and 5% (w/v) NaCl at 37°C, pH 6.5 for 3 days. The optimum pH, salt concentration and temperature for the protease activity were pH 8, 15% (w/v) NaCl and 60°C, respectively. Thus, the enzyme was salt-tolerant and slightly thermoalkaliphilic. The protease activity was strongly inhibited (77.62%) by chymostatin. Therefore, the protease of strain TKNR13-3 was serine protease type chymotrypsin. Activity stained-substrate gel of the crude protease indicated the presence of several proteases with the estimated molecular mass of 12, 21, 29, 39 and 49 kDa.
Key words: Halophilic bacteria, Virgibacillus halodenitrificans, protease, fermented shrimp paste.