Journal of Infectious Diseases and Treatment Open Access

Metabolic strategies boosting survival and functionality of beneficial lactic acid bacteria

Joint Event on 6^th World Congress and Expo on Applied Microbiology & 8^th Edition of International Conference on Antibiotics, Antimicrobials & Resistance & 12^th International Conference on Allergy & Immunology

October 21-22, 2019 Rome, Italy

Teresa Zotta, Annamaria Ricciardi and Eugenio Parente

Istituto di Scienze dell��?Alimentazione-CNR, Italy Universita degli Studi della Basilicata, Italy

Posters & Accepted Abstracts: J Infec Dis Treat

Abstract:

Statement of the problem: Lactic acid bacteria (LAB) are used as starter and adjunct cultures in the production of many fermented and functional foods, and as probiotics in different pharmaceutical preparations. In some LAB (mainly Lactococcus lactis, Lactobacillus casei, L. plantarum) the shift from anaerobic fermentative metabolism to aerobic respiration may result in several physiological advantages, including increase in biomass, production of ROSscavenging enzymes and robustness to stresses. Aerobic cultivation, moreover, alters the central carbon metabolism, re-routing pyruvate away from lactate (homofermentative LAB) or from lactate and ethanol (heterofermentative LAB), and others metabolites (e.g. acetate, acetoin, diacetyl) may be accumulated.

Methodology and Theoretical Orientation: Our group studied the aerobic and respiratory metabolism of some beneficial lactobacilli (mainly in L. casei and L. plantarum) through physiological, metabolic, transcriptomic and proteomic approaches.

Findings: Respirative phenotypes had improved antioxidant capabilities, catalase activities, survival to oxidative, long-term starvation and freeze-drying stresses compared to anaerobically growing cells. Aerobic and respiratory growth significantly affected the production of organic acids and volatile organic compounds in Lactobacillus strains. Changes in proteome and genes expression were principally related to proteins involved in energy and carbon metabolism and stress response. Respirative L. casei strains improved the quality of different fermented foods (e.g. sourdoughs, Cheddar-type cheeses, i.e. prevention of oxidative processes and production of desirable aroma compounds) and were used for the production of diacetyl, acetoin and starter biomass from cheese whey permeate (dairy waste utilisation).

Conclusion and Significance: Aerobic respiration may be industrially exploited to develop more competitive and functional starter and/or probiotic cultures.