Breeding Of High-Yield Strain For Cephalosporin C And Research Of Fermentation Characteristics

In this article, Physical chemical mutation, retional screening and genome shuffling techniques were used to improve the production of cephalosporin C by Acremonium chrysogenum ys-3 and got a high-producing strain G4-13. Then we analyzed its characteristics of fermentation, which provided some useful ideas in strain optimiziation.First, the strain Acremonium chrysogenum ys-3 was mutated by UV and nitrous in following condition: 30 W, 15 cm and 120 s in UV mutagenesis and 50 mmol/L, 120 s in nitrous mutagenesis. Then the two methods for a complex mutagenesis were combined, and 879 mutations were screened through the agar column tray high-throughput method. Finally a best strain FH-127 was got, whose production increased 80% than the origin.Then FH-127 was performed to mutated with rational screening by malonic acid(1%), heavy metal copper ions(0.06%) and cephalosporin C sodium salt(8 g/L) as selection pressure which were choose by the biosynthesis pathway analysis. In this period, 187 strains were screened under 1% malonic acid pressre, 269 under copper ions and 273 strains under CPC. After the agar column tray high-throughput screening, T-01069, TB-69068, TBC-68187, TBC-68071 were obtained, which could be used in the following Genome shuffling.The cell phase, enzymolysis duration and the hypotonic solution were firstly optimized in protoplast preparation. After killing the parental strains by heat and UV, the cells were fused with 30% PEG 6000 as inducer for 10 min. fusants were regenerated on PDA agar and mixed as multiparental strains for several subsequent shuffling. Finally, a high CPC producing strain G4-13 was got, whose yield than the origin.After genetic stability experiment of the final selected high-yield strains, its fermentation characteristic was analyzed, and the addition of soybean oil was reduced. Results of further research showed that weakly polar fractions of soybean oil showed more relatively with the CPC yield. Then we optimized its fermentation which shorttened the fermentation cycle and reduced the soybean oil addtion. Our work supplied some useful ideas for industrial application.