Biology of Reactive Oxygen Species, Oxidative Stress, and Antioxidants in Lactic Acid Bacteria
Marta C.T. Leite, Bryan Troxell, Jose M. Bruno-Bárcena and Hosni M. Hassan
from: Probiotics and Prebiotics: Current Research and Future Trends (Edited by: Koen Venema and Ana Paula do Carmo). Caister Academic Press, U.K. (2015) Pages: 205-218.
Lactic acid bacteria (LAB) are important in food fermentations and in human health. Due to their physiological and ecological heterogeneity, they encounter a variety of stressors including acid, osmolality, heat, bile-salt, and oxygen. LAB are exposed to oxidative stress caused by the partially reduced reactive oxygen species (ROS) generated from endogenous sources as well as from the environment. Findings over the past fifty years have demonstrated that this group of organisms comprise a heterogeneous mixture of different genera, where some members of the group have the capacity to synthesis antioxidant enzymes like Mn-containing superoxide dismutase (MnSOD), non-heme catalases (i.e., Mn-containing catalase: MnKat), and heme catalases (when provided with exogenous source of heme). Furthermore, some members of the group can accumulate large intracellular concentrations of manganese to use in the detoxification of ROS. In this chapter, we discuss the natural defenses against ROS in LAB as well as the technological practices used in the food and nutraceutical industries to protect LAB from oxidative stress and loss of viability during processing and storage read more ...