Abstract:To find an effective method for the rapid detection of natamycin and an accurate analysis of biological potency during solid-phase fermentation, three methods including high-performance liquid chromatography (HPLC), ultraviolet spectroscopy, and the cylinder-plate method were used to determine the natamycin content in the product of a batch of Streptomyces glvosporue during solid-state fermentation. The natamycin content in the solid fermentation product determined by HPLC and ultraviolet spectroscopy was 2351.52 mg/L and 2280.16 mg/L, respectively. The former showed good accuracy and reproducibility, while the accuracy of latter was 96.97% of the former (assigning the accuracy of HPLC method as 100%) and proved to be applicable for the rapid determination of natamycin content during solid fermentation. The average potency of natamycin determined by the cylinder-plate method was 1979.87 mg/L, and using an improved cylinder-plate method was 1990.29 mg/L when n-hexane was used in combination with methanol as the solvent. The accuracy of HPLC determined result increased from 84.20% to 84.64% using the cylinder-plate method (assigning the accuracy of HPLC method as 100%). The results indicated that n-hexane could effectively control the volatility of methanol, and improved the accuracy and concentration range for measurements using the cylinder-plate method, without having an antimicrobial effect.
