Abstract:

Objective To investigate the oxalate-degrading abilities of 10 strains of lactic acid bacteria for yoghourt fermentation. Methods Ten different strains of lactic acid bacteria (L.acidophilus, L.paracasei, Enterococcaceae faecium, B. lactis, B. adolescentis, B. infantis, B.longum, Lactococcus lactis subsp. Cremori, L.bulgaricus and S. thermophilus) were cultured separately in culture fluid containing 5 mmol/L oxalate. Seventy-two hours after culture, the concentrations of oxalate and lactic acid bacteria were detected. Besides, blank control cultured without lactic acid bacteria was established. Results Seventy-two hours after culture, the concentrations of all the 10 strains of lactic acid bacteria were significantly higher than those before culture (P<0.01). Compared with blank control, the concentrations of oxalate in the culture fluid with 10 strains of lactic acid bacteria decreased 72 h after culture, and were significantly different from those before culture for L.acidophilus, Lactococcus lactis subsp. Cremori, B.longum, B. adolescentis and B. lactis (P<0.05 or P<0.01). The oxalate-degrading rate of B. lactis was the highest (29.03％), and that of Enterococcaceae faecium was the lowest (0.23％). The correlation analysis revealed that there was no significant correlation between times of proliferation and oxalate-degrading rates (r=0.435 7, P=0.208 2). Conclusion All of the 10 strains of lactic acid bacteria for yoghourt fermentation have the ability of oxalate degrading, and there is no correlation between lactic acid bacteria proliferation and oxalate degradation.

Key words: oxalate, degradation, lactic acid bacteria, yoghourt