title: Short communication: effect of oxygen on symbiosis between Lactobacillus bulgaricus and Streptococcus thermophilus.
abstract: Lactobacillus delbrueckii ssp. bulgaricus (L. bulgaricus) and Streptococcus thermophilus are traditionally used for the manufacture of yogurt. It is said that a symbiotic relationship exists between Strep. thermophilus and L. bulgaricus and this decreases fermentation time. It is well known that L. bulgaricus is stimulated by the formate produced by Strep. thermophilus, and Strep. thermophilus is stimulated by free amino acids and peptides liberated from milk proteins by L. bulgaricus in symbiotic fermentation. We found that acid production by starter culture LB81 composed of L. bulgaricus 2038 and Strep. thermophilus 1131 was greatly accelerated by decreasing dissolved oxygen (DO) to almost 0 mg/kg in the yogurt mix (reduced dissolved oxygen fermentation) and that DO interferes with the symbiotic relationship between L. bulgaricus 2038 and Strep. thermophilus 1131. We attributed the acceleration of acid production of LB81 by reduced dissolved oxygen fermentation mainly to the acceleration of formate production and the suppression of acid production of LB81 by DO mainly to the suppression of formate production.
authors.affiliation: Research and Development Laboratories, 540 Naruda, Odawara, Kanagawa 250-0862, Japan. hiroshi.horiuchi@meiji.com
authors.forename: H
authors.initials: H
authors.lastname: Horiuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Sasaki
mesh_terms: D005285:Fermentation / Q000187:drug effects; D005561:Formates / Q000378:metabolism; D007778:Lactobacillus / Q000187:drug effects* / Q000502:physiology; D010100:Oxygen / Q000494:pharmacology*; D048249:Streptococcus thermophilus / Q000187:drug effects* / Q000502:physiology; D013559:Symbiosis / Q000187:drug effects*; D013997:Time Factors; D015014:Yogurt / Q000382:microbiology
chemical_list: D005561:Formates; D010100:Oxygen