Respirative metabolism improves the growth performance and stress response properties of Lactiplantibacillus plantarum SXC48

Oxygen always has negative effects on both growth and survival of the facultatively anaerobic lactic acid bacteria (LAB). Adding respiratory cofactors (hemin and menaquinone) may activate the respiratory metabolism of LAB, thereby affecting its growth performance and tolerance to stresses. The aim of this study was to assess the growth performance, stress response properties, oxidase activity and cell wall changes of Lactiplantibacillus plantarum SXC48 grown in aerobiosis without (aerobic conditions) and with respiratory cofactors supplementation (respiration), and anaerobiosis. The results showed that aerobic cultivation impaired the growth and survival of SXC48. Respiratory cultivation markedly improved the growth and the robustness of SXC48, as evidenced by increased biomass yield, oxygen uptake, antioxidant capacity and long-term survival during cold storage, compared to aerobic and anaerobic cultivation. In addition, oxidase activities were higher under respiratory conditions than under aerobic and anaerobic conditions. The culture supernatant had higher antioxidant capacity than cells and cell extracts of disrupted cells regardless of incubation conditions. Aeration roughened the cell wall surface. Therefore, Lb. plantarum SXC48 might be better adapted to respiration than to traditional anaerobic cultivation. These results may have significant technological contribution to the production, industrial process and biotechnological applications of starters and probiotics.