Characterization of Streptococcus oligofermentans sucrose metabolism demonstrates reduced pyruvic and lactic acid production

• Published in: Chinese medical journal Vol. 124; no. 21; pp. 3499 - 3503
• Main Authors: Bao, Xu-Dong, Yue, Lin, Gao, Xue-Jun
• Format: Journal Article
• Language: English
• Published: China Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology, Beijing 100081, China 05.11.2011
• Subjects: L-Lactate Dehydrogenase - metabolism; Lactic Acid - metabolism; Pyruvic Acid - metabolism; Streptococcus - metabolism; Sucrose - metabolism; 丙酮酸; 乳酸生产; 发酵过程; 变形链球菌; 生化机制; 蔗糖代谢; 表征; 高效毛细管电泳; Streptococcus oligofermentans; lactic acid; lactate dehydrogenase; pyruvic acid
• ISSN: 0366-6999; 2542-5641; 2542-5641
• DOI: 10.3760/cma.j.issn.0366-6999.2011.21.012

Background Streptococcus （S.） oligofermentans is a newly identified bacteria with a yet to be defined mechanism of sucrose metabolism that results in acid production. This study aimed to investigate the biochemical mechanisms of S. oligoferm-entans glucose metaolism. Methods The S. oligofermentans LMG21532, Lactobacillus （L.） fermentum 38 and the S. mutans UA140 were used to characterize sucrose metabolism by measuring lactate dehydrogenase （LDH） activity and lactic acid production. Continuous dynamics and high performance capillary electrophoresis were used to determine LDH activity and lactic acid production, respectively, from bacteria collected at 0, 10 and 30 minutes after cultured in 10% sucrose. Results These analyses demonstrated that LDH activity of the three bacterial strains examined remained stable but significantly different throughout the sucrose fermentation process. The S. oligofermentans LDH activity （（0.61±0.05） U/mg） was significantly lower than that of L. fermentum （（52.91±8.97） U/mg）. In addition, the S. oligofermentans total lactate production （（0.048±0.021） mmol/L） was also significantly lower than that of L. fermentum （（0.958±0.201） mmol/L）. Although the S. oligofermentans LDH production was almost double of that produced by S. mutans （（0.32±0.07） U/mg）, lactic acid production was approximately one sixth that of S. mutans （（0.296±0.058） mmol/L）. Additional tests examining pyruvic acid production （the LDH substrate） demonstrated that lactic acid concentrations correlated with pyruvic acid production. That is, pyruvic acid production by S. oligofermentans was undetectable following sucrose incubation, however, （0.074±0.024） and （0.175±0.098） mmol/L pyruvic acid were produced by S. mutans and L. fermentum, respectively. Conclusion S. oligofermentans is incapable of fermenting carbohydrates to produce enough pyruvic acid, which results in reduced lactic acid production.