Biochemical activities of Brochothrix thermosphacta

Activities of 19 hydrolases were estimated in cell suspensions of 40 Brochothrix thermosphacta strains, isolated from meat and meat products packaged under various conditions, by using API ZYM® test. These strains produced: acidic phosphatase, esterase C4, esterase/lipase C8, α-chymotrypsin, leucine arylamidase, β-glucosidase and α-glucosidase. The predominating biotype produced only the first four of the listed enzymes. The extracellular lipolytic activity for bromo-chloro-indolyl-caprylate was detected only in culture broth supernatants of 4 strains thereby indicating that esterase/lipase C8 is cell-bound. 13 of the strains displayed proteolytic activity for albumin at 4 °C (0.31–2.07 U) while 9 strains showed this activity at 25 °C (0.11–1.21 U). Only 4 strains digested albumin at both temperatures. Thus the meat spoilage potential of B. thermosphacta strains results not only from digestion of carbohydrates but also from their proteolytic activity.

► Brochothrix thermosphacta show proteolytic activity in 4 and 25 °C.
► The proteolytic activity is independent of bacterial origin.
► Brochothrix thermosphacta show extracellular lipolytic activity only in 25 °C.
► B. thermosphacta lipases preferring esters of glycerol and short chain fatty acids.