Probiotic Properties and Antibiotic Resistance Pattern of Bacillus spp. Isolated from Two Types of Fermented Locust Bean (iru)

Abstract

Bacillus spp. associated with two types of fermented African locust beans iru woro and iru pete were isolated and screened for probiotic potentials using standard microbiological techniques. The total bacterial counts for iru woro (pH 8.4) and iru pete (with pH 8.1) were 6.4314 and 6.4771 log10CFU/g respectively. In the two samples, the load of aerobic sporeformers were 6.2068 and 6.2553 log10CFU/g. In the samples Bacillus subtilis had the highest occurrence (44%), followed by B. lichenliformis (28%) and B. megaterium (24%) while B. coagulans had the least (4%). Only 28% of Bacillus isolates produced caseinase, while 28% produced haemolysin. Majority of these isolates showed tolerance to salt at concentrations less than 5% and also grew fairly at pH tending to neutral. Bacillus subtilis P14, Bacillus lichenliformis P12 and Bacillus megaterium P6 grew at 3.0% bile. Percentage hydophobicity, auto-aggregation and co-aggregation of the isolates ranged from -49.00 to 65.00%, -53.00 to 84.00% and -69.44 to 36.08% respectively. High level of antibiotic resistance (especially to first line antibiotics) was recorded among isolates. Most of the Bacillus species isolated from the iru samples had very poor probiotic properties. Molecular and in vitro probiotic properties of promising candidates are still open to investigation.