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Characterization of cellulase‐producing bacteria from the digestive tract of tilapia, Oreochromis mossambica (Peters) and grass carp, Ctenopharyngodon idella (Valenciennes)
Author(s) -
Saha Sangbrita,
Roy Raj Narayan,
Sen Sukanta Kumar,
Ray Arun Kumar
Publication year - 2006
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2006.01442.x
Subject(s) - grass carp , biology , amylase , cellulase , tilapia , protease , food science , microbiology and biotechnology , bacillus megaterium , oreochromis , agar plate , agar , bacteria , bacillus (shape) , botany , biochemistry , cellulose , enzyme , fish <actinopterygii> , fishery , genetics
Isolation and characterization of cellulase‐producing aeorobic bacterial flora in the intestine of omnivorous tilapia ( Oreochromis mossambica ) and phytophagous Chinese grass carp ( Ctenopharyngodon idella ) have been carried out using selective carboxymethylcellulose‐agar (CMC‐agar) medium. The cellulolytic activity was measured both qualitatively and quantitatively. It was found that the ability of different strains in degrading cellulose varies within a wide range. Among the strains isolated from the gut of each test fish, TM1 and CI3 isolated from O. mossambica and C. idella , respectively exhibited maximum cellulolytic activity (67.02 and 35.8 U mL −1 respectively). Pure cultures of these strains were selected for morphological, physiological and biochemical characterization. On the basis of these tests, the isolated strains were identified as Bacillus circulans (TM1) and Bacillus megaterium (CI3). Both the strains are rod‐shaped, motile and show better temperature (15–42°C) and pH (5–11) tolerance. The selected strains were further quantitatively assayed for amylase and protease activities. Maximum amylase and protease activities were exhibited by TM1 and CI3 respectively. Information generated from the present study might contribute towards better‐feed formulation incorporating plant ingredients.