Investigation of Factors Affecting Aerobic and Respiratory Growth in the Oxygen-Tolerant Strain Lactobacillus casei N87.
Aerobic and respiratory cultivations provide benefits for some lactic acid bacteria (LAB). Growth, metabolites, enzymatic activities (lactate dehydrogenase; pyruvate and NADH oxidases, NADH peroxidase; catalase), antioxidant capability and stress tolerance of Lactobacillus casei N87 were evaluated in anaerobic, aerobic and respiratory (aerobiosis with heme and menaquinone supplementation) batch cultivations with different dissolved oxygen (DO) concentrations. The expression of pox (pyruvate oxidase) and cydABCD operon (cytochrome bd oxidase complex) was quantified by quantitative Real Time polymerase chain reaction. Respiration increased biomass production compared to anaerobiosis and unsupplemented aerobiosis, and altered the central metabolism rerouting pyruvate away from lactate accumulation. All enzymatic activities, except lactate dehydrogenase, were higher in respiratory cultures, while unsupplemented aerobiosis with 60% of DO promoted H2O2 and free radical accumulation. Respiration improved the survival to oxidative and freeze-drying stresses, while significant numbers of dead, damaged and viable but not cultivable cells were found in unsupplemented aerobic cultures (60% DO). Analysis of gene expression suggested that the activation of aerobic and respiratory pathways occurred during the exponential growth phase, and that O2 and hemin induced, respectively, the transcription of pox and cydABCD genes. Respiratory cultivation might be a natural strategy to improve functional and technological properties of L. casei.
Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università degli Studi della Basilicata, Potenza, Italy.
Rocco G
RG
Ianniello
Istituto di Scienze dell'Alimentazione-CNR, Avellino, Italy.
Teresa
http://orcid.org/0000-0001-8228-6804
T
Zotta
Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università degli Studi della Basilicata, Potenza, Italy.
Attilio
A
Matera
Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università degli Studi della Basilicata, Potenza, Italy.
Francesco
F
Genovese
Dipartimento di Scienze, Università degli Studi della Basilicata, Potenza, Italy.
Eugenio
E
Parente
Scuola di Scienze Agrarie, Forestali, Alimentari e Ambientali, Università degli Studi della Basilicata, Potenza, Italy.
Annamaria
A
Ricciardi
D000332:Aerobiosis / Q000187:drug effects; D000693:Anaerobiosis / Q000187:drug effects; D000975:Antioxidants / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D006418:Heme / Q000494:pharmacology; D007700:Kinetics; D007780:Lacticaseibacillus casei / Q000187:drug effects / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D009876:Operon / Q000235:genetics; D018384:Oxidative Stress / Q000187:drug effects; D010100:Oxygen / Q000378:metabolism*; D024482:Vitamin K 2 / Q000494:pharmacology
D000975:Antioxidants; D024482:Vitamin K 2; D006418:Heme; D010100:Oxygen