Optimal production conditions, extraction, partial purification and characterization of inhibitory compound(s) produced by Streptomyces Ds-104 isolate against multi-drug resistant Candida albicans

A Streptomyces Ds-104 isolate was found to inhibit four multi-drug resistant Candida albicans pathogens with an optimal production of the inhibitory compound(s) in starch, casein, nitrate broth (SCNB) and inhibition zone diameters ranging between 14 and 18 mm. These were significantly different (P= 0.05) from what was obtained in nutrient, oatmeal, inorganic salt starch, and yeast extract, malt extract broth media. When Ds-104 isolate was grown in SCNB supplemented with glucose, 15 g l⁻¹; KNO₃, 2.5 g l⁻¹; NaCl, 10 g l⁻¹; and no KH₂PO₄, and incubated at 28°C for 10 days with shaking at 100 rpm, the inhibition zone diameter ranged between 25 and 30 mm, increased by 1.5-folds and significantly different (P = 0.05) from the other culture supplements and conditions. The minimum inhibitory concentration (MIC), U.V absorption spectrum and TLC analysis of the water soluble of evaporated ethanol crude extract revealed MIC of 6.25 mg mL⁻¹, maximum absorbance at 205 nm, and an Rf value of 0.75, respectively. The Rf value and UV absorption spectrum of the active compound(s) in the crude extract are different from the tested drugs (fluconazole and amphotericin B) which may suggest the novelty of the inhibitory compound(s) produced by the Streptomyces Ds-104 isolate.