Production and characterization of alkaline protease from hemoglobin-degrading Bacillus pumilus NJM4 to produce fermented blood meal

Abstract

The aim of the research was to isolate the hemoglobin-degrading bacterial strain to produce fermented blood meal and to characterize the protease produced by this strain. The strain NJM4, a kind of hemoglobin-degrading bacterial strain, was isolated by blood agar plates from slaughterhouse and identified as a Bacillus pumilus by physiological, biochemical, and morphological characteristics and by 16S rRNA gene sequencing. Bacillus pumilus NJM4 could degrade hemoglobin up to 85% in 36h under the laboratory conditions. The optimal conditions for protease production was achieved at an initial pH level of 8.67, inoculum size of 4%, incubation temperature of 37°C, and agitation rate 200rpm. The optimum pH and temperature of hemoglobin-degrading proteases were at 9.0 and 50°C, respectively. The protease activity was slightly decreased in presence of Ca(2+) and DTT. It was significantly inhibited in the presence of PMSF and EDTA identifying it as alkaline serine-metalloproteinase. Bacillus pumilus NJM4 and hemoglobin-degrading proteases provide potential use for biotechnological process of fermentation and enzymolysis blood meal as animal feed supplement.