Evaluation of Protease-producing Ability of Fish Gut Isolate Bacillus cereus for Aqua Feed

Abstract

Extracellular protease production by Bacillus cereus isolated from the intestine of fish Mugil cephalus has been investigated in shake-flask experiment using different preparations of tuna-processing waste such as raw fish meat, defatted fish meat, alkali hydrolysate, and acid hydrolysate as nitrogen source. Among the tuna preparations tested, defatted fish meat supported the maximum protease production (134.57±0.47 U ml −1 ), and 3% concentration of the same was found to be optimum for maximizing the protease production (178.50±0.28 U ml −1 ). Effect of carbon sources on protease production in the optimized concentration of defatted tuna fish meat revealed that galactose aided the higher protease production (259.83± 0.04 U ml -1 ) than the other tested carbon sources and a concentration of 1.5% galactose registered as optimum to enhance the protease production (289.40±0.16 U ml −1 ). The halotolerancy of B. cereus for protease production indicated that 3% of sodium chloride was optimum to yield maximum protease (301.63±0.20 U ml −1 ). Among the surfactants tested, protease production was high in Triton X 100-added medium (298.63±0.12 U ml −1 ) when compared to other surfactants, and its optimum concentration recorded was 0.8% (320.57 ± 0.17 U ml −1 ) for more protease production. Partial characterization of crude enzyme revealed that pH 7.0 (278.90±0.08 U ml −1 ) and 60°C temperature (332.37±0.18 U ml −1 ) were optimum for better protease activity by B. cereus.

Response surface method to optimize the low cost medium for protease production using anchovy meal from ascidian associated Bacillus sp. GA CAS10

“…The optimal levels of the four selected variables (anchovy waste, K 2 PHO 4 , NaCl and temperature) and their interactions were then examined by a central composite design. Present findings are in line with several reports showing the enhancement of protease production in the presence of fish meal as nitrogen sources by Bacillus mojavensis A21 (Haddar et al, 2010;Esakkiraj et al, 2009, Pseudomonas aeruginosa MN7 (Triki-Ellouz et al, 2003).…”

Distribution of extracellular enzyme-producing bacteria in the digestive tracts of 4 brackish water fish species

“…However, the endosymbiotic community among the brackish water fish species has remained poorly investigated (Esakkiraj et al, 2009). Digestive tracts of endotherms are colonized mainly by obligate anaerobes (Finegold et al, 1983), while the predominant bacterial genera isolated from most fish guts have been aerobes or facultative anaerobes (Trust and Sparrow, 1974;Horsley, 1977;Sakata, 1990;Bairagi et al, 2002;Ghosh et al, 2002a).…”

Enhancement of Phytase Production from a New Probiotic Strain Bacillus subtilis P6

“…A pH beyond the optimum level may interfere with the amino acid composition of the enzyme decreasing its activity (Esakkiraj et al, 2009). Largely, bacteria prefer pH around 5.0-7.0 for best growth and phytase production (Vohra and Satyanarayana, 2003).…”