Percentage and Concentration of the Antibiotic Polymyxin in Extracts of Four Species Belonging to the Genus Bacillus

Abstract

The study included the determination of the antibiotic (Polymyxin) and its proportions in the organic extracts of marine species of the genus Bacillus, namely (B. cereus, B. subtilis, B. circulans, B. polymyxa), which were isolated from beach sediment samples from the Afamia region with geographical coordinates (35°76'19.1"N; 35°54'19.3"E) It is an open area affected by tourist activities, sewage canals, and ship waste. To obtain organic extracts of bacterial isolates, the optimal conditions for separating and purifying these antibiotics were determined at the lowest economic cost, given the importance of these antibiotics in the pharmaceutical industries and their effective impact on pathogenic microbes and cancer cells. The results showed that after separating the low-density liquid layer (the upper layer) from the high-density liquid layer (the lower layer) and measuring the absorbance using a spectrophotometer for each antibiotic, the optimal conditions for purifying and isolating antibiotics were at a centrifugation speed of 4000 rpm, a centrifugation time of (30) minutes, and a temperature of -5°C. The results showed that the percentage of the antibiotic polymyxin upon centrifugation at -5°C for 30 minutes was 91.30% for the extract of B. subtilis, 97.91% for the extract of B. polymyxa and 88.23% for the extract of B. circulans.

Keywords: Bacillus; Antibiotic; Spectrophotometer

Citation

Rami Basem Hammod. Percentage and Concentration of the Antibiotic Polymyxin in Extracts of Four Species Belonging to the Genus Bacillus. WebLog J Infect Dis. wjid.2026.g2305. https://doi.org/10.5281/zenodo.21740372