Screening of oxalate degrading lactic acid bacteria of food origin

Abstract

A screening for oxalate degrading abilities was initially carried on within Lactic Acid Bacteria cultures of different food origin. Seventy-nine strains were drop-inoculated onto MRS agar plates containing calcium oxalate. By comparing colonies diameters, 31 strains were used to inoculate, in parallel, MRS and MRS modified by sodium oxalate addition. Differences in the strains’ growth were assessed by colony forming unit counts. For two strains, the growth in oxalate enriched medium was significantly higher; while, for eleven strains an opposite behaviour was recorded. Two strains – probiotic Lactobacillus rhamnosus LbGG and Enterococcus faecalis 59 – were chosen. The first strain appeared to be able to metabolize oxalate more efficiently than the other tested cultures, while strain 59 appeared unable to gather advantage by oxalates and, indeed, appeared to be inhibited by the salt presence in the medium. Outcomes revealed that higher glucose concentrations may favour oxalates utilization. In MRS with oxalate, but without glucose, citrate was completely metabolized. Evaluation along time confirmed that the oxalate degradation is more significant in presence of glucose. Outcomes may represent a good start for the development of a safe and even probiotic culture able to lower the oxalates content of food.

Comparison of nutrients and microbial density in goji berry juice during lactic acid fermentation using four lactic acid bacteria strains

“…As shown in Table 1, the concentration of oxalic acid in all strains fermented juices displayed a declining trend during the fermentation. It is reported that oxalic acid could be decomposed by some lactic acid bacteria (Murru et al., 2017). Concerning the evolution of acetic acid, a significant decline was observed for L. acidophilus and L. plantarum C8‐1 fermented juices, while negligible modifications were found for L. brevis and L. plantarum Lp39.…”

The effects of inulin as a prebiotic supplement and the synbiotic interactions of probiotics to improve oxalate degrading activity

“…These species are important inhabitants of human intestine and are widely used in probiotic products (Ambalam et al ., ; Shokryazdan et al ., ; Archer & Halam, ). Up to now, few studies were carried out on the oxalate degrading capacity of L. rhamnosus, L. fermentum and L. brevis strains in dairy products (Campieri et al ., ; Turroni et al ., ; Gomathi et al ., ; Murru et al ., ). These researchers studied oxalate degrading activity in MRS medium containing oxalate.…”

Activity of probiotics from food origin for oxalate degradation

“…The bacterial count (cfu/mL) was performed for the selected isolates in MRS broth containing 20 mmol /L of calcium oxalate (MRS-ox). After incubation at 37°C for 72 h, bacterial count was assessed by plate count (cfu/mL) on MRS agar as described by Murru et al (2017).…”

“…The Lactobacillus isolates able to degrade oxalate were inoculated separately and in combination into MRS broth tubes (El-shafei et al 2008). The tubes were incubated at 37 °C for 48 hours then after that, each tube was serially diluted then plated on MRS agar containing 50 mmol /L calcium oxalate (MRS-ox) (Murru et al 2017). The clear area around the bacterial colonies was an indication of oxalate degradation .Clear areas was recorded to determine the combined effect between the cultures.…”