Permeabilization of Streptococcus thermophilus and the expression of beta-galactosidase

• Published in: Enzyme and microbial technology Vol. 16; no. 7; pp. 573 - 576
• Main Authors: Somkuti, George A., Steinberg, Dennis H.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 1994; Elsevier Science
• Subjects: Action of physical and chemical agents on bacteria; Bacteriology; Biological and medical sciences; Biology of microorganisms of confirmed or potential industrial interest; Biotechnology; cell permeabilization; detergent effects; Fundamental and applied biological sciences. Psychology; Microbiology; Miscellaneous; Mission oriented research; S. thermophilus; Streptococcus thermophilus; β-Galactosidase; detergent effects; β-Galactosidase; cell permeabilization; S. thermophilus; Detergent; Enzyme; Permeabilizing; Gene expression; Streptococcaceae; Streptococcus salivarius subsp. thermophilus; Glycosidases; Bile acid; Microorganism culture; Bacteria; Hydrolases; Micrococcales; O-Glycosidases; Viability
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/0141-0229(94)90121-X

Studies were carried out to determine the efficacy of several permeabilizing agents in inducing high-level expression of β-galactosidase in Streptococcus thermophilus. Sodium dodecyl sulfate, Triton X-100, sodium deoxycholate, and one commercial bile acid preparation were effective as membrane destabilizing agents allowing lactose influx and hydrolysis by cytoplasmic β-galactosidase in treated cells. Cells exposed to Oxgall or Triton X-100 displayed 15 times higher levels of β-galactosidase activity than control cells. Detergent treatment also induced extensive cell death or significant injury to cell populations resulting in long delays before resumption of growth. A permeabilized suspension of S. thermophilus corresponding to 10 8 cfu ml −1 released 87% of glucose available in a 5% lactose solution within 10 min at 50°;C.