Fermentative Properties of Proteolytic Pediococcus Strains Isolated from Salt Fermented Fish Hydrolysate Prepared Using Freshwater Fish Rohu (Labeo rohita)

ABSTRACT

Salt fermented fish hydrolysate (SFFH) was prepared from freshwater fish Rohu (Labeo rohita), an Indian major carp, using salt at room temperature for 50 days. Total lactic acid bacteria (LAB) counts of SFFH prepared using 20% and 30% NaCl (w/w) were found to be in the range of 5.83–7.25 log cfu/ml and 3.93–5.46 log cfu/ml, respectively, whereas the log cfu/ml values for the halotolerant LAB counts varied from 2.09 to 7.17 and 2.02 to 4.77, respectively. Out of 96 isolates from SFFH, 21 isolates were screened based on their pH reducing ability, total titratable acidity, and proteolytic properties. Morphological, biochemical, and molecular characterization of four selected LAB strains were carried out. The isolates FSAP3-3 (Pediococcus pentosaceus), FSBP4-40 (Pediococcus pentosaceus), FSBP16-40 (Pediococcus pentosaceus), and FSBP28-50 (Pediococcus acidilactici) showed both halotolerant and proteolytic properties. The identified LAB isolates showed antagonistic properties against several human pathogens and exhibited sensitivity toward a broad spectrum of antibiotics. All the identified LAB isolates showed excellent proteolytic activity and phosphohydrolase activity. These halotolerant LAB isolates that had both proteolytic properties and acidifying ability have the potential for application in an acceleration of fermentation to produce salted fish products (i.e., fish sauce, fish paste, fish mince, etc.).

KEYWORDS:

• Fish sauce
• halotolerant
• lactic acid bacteria
• Pediococcus
• proteolytic

Acknowledgments

GSS thanks the University Grants Commission and Department of Collegiate Education for the Teacher Fellowship for his doctoral program. Dr. SG and Dr. NB are thankful to University of Mysore (Mysuru) and CSIR-CFTRI (Mysuru), respectively, for the permission to collaborate on this work. We are grateful to Dr. Prakash M. Halami for his valuable guidance in identifying LAB isolates.