Stress resistance of the biofilm and planktonic forms of Lactobacillus delbrueckii in adverse environments
Year: 2025
Type: article
Abstract: Biofilm and planktonic forms are different kinds of self-protection mechanisms in microorganisms for resistance to adverse environments. The research explored the physicochemical properties, antimicrobial, and antioxidant activities of Lactobacillus delbrueckii (L. delbrueckii) 5E, focusing on the biofilm's stress tolerance. L. delbrueckii 5E's high lactic acid production (709.1 g·L-1) enhances its antimicrobial activity, which is pH-dependent and decreases when the supernatant is adjusted to pH 6.5. The cell-free fermentation supernatant, bacterial suspension, and cell-free extract of L. delbrueckii 5E showed significant scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and superoxide anion radicals. L. delbrueckii 5E formed biofilms with a bacterial count of 9.00 × 106 CFU·mL-1 on polyacrylonitrile electrospun membranes. Stress-tolerance tests indicated that the biofilm form of L. delbrueckii 5E exhibited superior survival under high temperatures, osmotic pressures, bile salts, potassium sorbate, and H2O2 exposure. The biofilm consistently released free bacteria, maintaining a stable total colony count of 106 CFU·mL-1. The remarkable antibacterial and antioxidant properties of L. delbrueckii 5E, along with its resilience to harsh environments, establish its potential for applications in the food industry.
Source: Letters in Applied Microbiology
Institution: Inner Mongolia Agricultural University
Language: English
Subfield: Food Science
Domain: Life Sciences
Open Access status: green
OpenAlex ID: W4408200721