Precursors Influence On The Composition Of Meleumycin And Investigation Of Mechanism

Through mutagenesis by UV and LiCl bind to the screening of agar block on Streptomyces mycarofaciens. N-20s-6,N-20s-13,N-20s-20 have been selected and biological value was 2461,2085,2127 respectively. The best mutant has increased by 50.1%.Sodium propionate, sodium acetate, methionine, alanine, valine, y-aminobutyric acid, serine were injected in medium in different concentration respectively. It was found that methionine was effectively and biological value of meleumycin has increased 61.9% after the methionine added in. Also, y-aminobutyric acid, serine, sodium acetate and sodium propionate made 23.2%,18%,31.8% and 35.5% increasing. Especially the 0.08% methionine made 135% increasing of midecamycinA1, one of the main role in meleumycin.Propional group plays a key role in the fermentation of meleumycin. We selected a substance which could offer a huge number of propionyl and injected in medium before inoculation. The midecamycin A1 has increased 55% when 0.2% propionyl has been added. And leucomycin A6, midecamycin D, leucomycin A8 have reduced 29%,78% 86% respectively. We presumed that the last two steps of midecamycin A1 synthesis were the propionylation of the macrocyclic ring of leucomycin V. Midecamycin A1 was the key intermediate substance during the synthesis of midecamycin A1.Sodium propionate is a cheaper substance, and which could increase the synthesis of midecamycin A1.0.06% sodium propionate was useful. The sodium propionate added in the medium before inoculation. The synthesis of midecamycin A1 has been promoted but leucomycin A6 has been inhibited. However, while the sodium propionate added at the time spot 12 hour. Both of them were inhibited. We found that the concentration of seed was 26.5%, it was the best time to inoculate. Sodium propionate was added at 12 hour which will cause diauxic growth. After 6 hours, strain became growing, and reached to the stationary phase at 54 hours which delayed almost 24 hours than control. However, the concentration of strain was more higher.