Cactus pear (Opuntia ficus-indica) cladode extracts as a growth medium for Lactobacillus species: the case of Lactobacillus reuteri and Lactobacillus mali.

Different commercially available culture media have been long in use for microorganisms. But in Tigray, Ethiopia, the high price and scarcity of these culture media on local market have made it difficult for microbial researchers to conduct their research. The aim of current study was to create a low-cost, locally accessible culture medium for Lactobacillus species growth using cladodes extracted from cactus pear (Opuntia ficus-indica) cladodes. Samples of cactus pear cladode were collected from Adigrat, Tigray, Ethiopia. Lactobacillus reuteri and Lactobacillus mali were the two bacterial species that were examined. Evaluation and comparison of Lactobacillus species growth on cactus pear cladode agar and broth (40, 20 and 13.33 g/L) with de Man, Rogosa, and Sharpe (MRS) medium (control) were conducted. Each prepared cactus pear cladode agar (CPCA) medium was transparent and light brown in color. The current finding shows that after 72 h of incubation, both tested Lactobacillus species produced small, spherical and white colonies on CPCA that lacked any pigments or odor. In comparison to other cactus pear cladode broths (40 and 13.33 g/L), the cactus pear cladode broth (20 g/L) showed the fastest exponential growth after 24–36 h of incubation. The bacterial colony counts in the cactus pear cladode broth (20 g/L) were higher than those in the other formulations (40 and 13.33 g/L), but they did not differ significantly (P < 0.05) when compared to MRS medium. This study showed that the cactus pear cladode (20 g/L) medium could be used as a culture medium for Lactobacillus growth. [ABSTRACT FROM AUTHOR]