Prevalence of Caseinase Enzyme in Bacteria

Abstract:

Caseinase is an enzyme implicated in the digestion of the milk protein, casein as well as other casein-like structural proteins. Caseinase is generally found in fungi as well as milk-spoiling soil bacteria such as /Bacillus/ sp., pathogenic bacteria such as /Pseudomonas/ sp. where it functions as a virulence factor, /Streptomyces/ sp. etc. Less is known about the distribution of the caseinase enzyme in other bacteria. In this study, a screen of caseinase-producing bacteria resulted in the identification of over 50 isolates of caseinase-producing bacteria. Caseinase was mostly present in bacteria from food and soil sources. Diverse food samples showed a surprising enrichment of human skin microflora, predominantly /Micrococcus/ spp. and /Staphylococcus/ spp., whereas caseinase-positive bacteria isolated from soil were mostly Bacillus spp. Not surprisingly, fermenting bacteria such as /Streptococcus/ sp. isolated from dairy products also contained caseinase. In addition, caseinase was also observed in /Aeromonas/ and /Enterobacter/ spp. isolated from wet environments reaffirming the presence of caseinase in potential pathogens. Studies are underway to identify caseinase-producing enzymes in these bacteria.