Mupirocin Screening Of Strain And Fermentation Technology Research

Mupirocin，obtained from Pseudomonas Fluorescens broth, is alocal external antibiotics used in the treatment of infection caursed byStaphylococcus, Streptococcus and some Gram-negative bacterium inclinic. This antibiotic has the advantage of no cross-resistance withother antibiotics, fewer adverse effects, easy to use and less costs.In this paper, mupirocin-producing strain improvement was carried.A high-yield and stable mutant SIPI-A.1036from P. FluorescensSIPI-A.1033, deposited in Lab., was obtained through series of naturalselection and UV mutation. The productivity of the mutant was178%higher than the parent strain.After series of studies in flask, optimized media and condition wereobtained. The optimized slant medium (g/L) was peptone10, beefextract3.0,NaCl5, agar20.0,pH7.4; seed medium (g/L) was yeastextract-5, peptone10.0, NaCl5.0, pH7.4; fermentation medium (g/L)was glucose10, glycerol50, cold-pressed soybean meal20, peanutpowder10, corn oil10.0,(NH4)2SO40.5, NH4Cl0.5, leucine-1.0, NaCl5.0,corn syrup5.0, CaCO35.0. The optimized slant culture conditions was at25℃for4days; seed culture condition was at25℃for24h;fermentation culture condition was initial pH6.8, temperature25℃,inoculum10%, medium volum30mL/500mL, rotation speed240rpm,culture period60h. The productivity under this optimized condition was75%higher than that under original condition.Applying above optimized condition at flask scale to10L jarfermentor, the results showed that the bacteria began to significantlybiosynthesize mupirocin soon after the bacteria entering thelogarithmic growth stage around6th hour. Both the rate of bacteriagrowth and antibiotic biosynthesisi reached maximum at about24thhour. After that, cells began to decline, but mupirocin was still biosynthesized slowly. The time caurse showed that mupirocinbiosynthesis reached maximum at70th hour while under shaking flaskcondition it reached maximum at60th hour.