Reasonable Selection And Metabolic Analysis For Lincomycin Strain

The soybean flour was replaced by cottonseed protein and peanut meal as main nitrogen sources for lincomycin production. The response surface methodology was used to optimize the biosynthesis medium of Streptomyces linconinensis. First, peanut meal, KH2PO4 and corn steep liquor were found to be the important factors by Plackett-Burman design. Then center concentration of the three important factors was determined by the steepest ascent search. And the optimal concentration of the three important factors was defined by response surface methodology. The result were 18 g/L peanut meal,0.4 g/L KH2PO4 and 1.2 g/L corn steep liquor. The average potency of lincomycin could reach 4268μg/ml by using the optimal medium, which was increased by 12%-17%compared with the original medium. Finally, We found metal ions and amino acid had effects on lincomycin production by comparison the differents between the original culture and the optimal one.Based on the structure of lincomycin, mutant strains, with resistance of feedback suppression of Isopropyl-β-D-thiogalactopyranoside (IPTG),which is an analog of methyl thiolincosamide, were thus selected and lincomycin production increased by 12-30%. IPTG was proved to be an inducer ofβ-D-galactosidase when it was added at the beginning of the culture. The production of lincomycin was increased by 10%with the addition of 2 mg/L IPTG at 0 h directly in the medium. IPTG can induce the degradation of the lactose to galactose, the addition of galactose was better than lactose, which can increase the yield of lincomycin by 20%,with the addition of 0.01%galactose at 0-48 h directly in the medium.The inhibitor of anthranilate synthetase—trimethylamine was found by shikimic acid pathway analysis, which change the metabolite flux, so that more metabolite flux turned to the direction of tyrosine synthesis. Experiments showed the potency was increased by 20%or so via adding 0.08%trimethylamine at 48h directly in the medium.