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Low-energy ion implantation as a novel mutagen has been increasingly applied in the microbial mutagenesis for its higher mutation frequency and wider mutation spectra.In this work,N~+ ion beam implantation was used to enhance Escherichia sp.in vitamin K_2 yield.Optimization of process parameters under submerged fermentation was carried out to improve the vitamin K_2yield of mutant FM5-632.The results indicate that an excellent mutant FM5-632 with a yield of 123.2±1.6 μg/L,that is four times that of the original strain,was achieved by eight successive implantations under the conditions of 15 keV and 60×2.6×l0~(13)ions/cm~2.A further optimization increased the yield of the mutant by 39.7%,i.e.172.1±1.2 μg/L which occurred in the mutant cultivated in the optimal fermentation culture medium composed of(per liter):15.31 g glycerol,10 g peptone,2.89 g yeast extract,5 g K2HPO_4,1 g NaCl,0.5 g MgSO_4·7H_2O and 0.04 g cedar wood oil,incubated at 33℃,pH 7.0 and 180 rpm for 120 h.  相似文献   
2.
发酵法生产新型营养强化剂--花生四烯酸   总被引:4,自引:0,他引:4  
本文研究了温度、PH、培养时间以及碳源、氮源等因素对高山被孢霉菌I49-N18的细胞生长、产油脂和花生四烯酸的影响,确定了该菌株发酵生产花生四烯酸的最佳培养基和最佳培养条件,使得其干菌体重(DW)可达25.9g/l,总脂(TL/DW)含量达36.6%,花生四烯酸(AA/TL)含量达71.0%。  相似文献   
3.
In order to generate a mutant of Bacillus subtilis with enhanced surface activity through low energy nitrogen ion beam implantation, the effects of energy and dose of ions implanted were studied. The morphological changes in the bacteria were observed by scanning electron microscope (SEM). The optimum condition of ions implantation, 20 keV of energy and 2.6 × 10^15N^+/cm^2 in dose, was determined. A mutant, B.s-E-8 was obtained, whose surface activity of 50-fold and 100-fold diluted cell-free Landy medium was as 5.6-fold and 17.4-fold as the wild strain. The microbial growth and biosurfactant production of both the mutant and the wild strain were compared. After purified by ultrafiltration and SOURCE 15PHE, the biosurfactant was determined to be a complex of surfactin family through analysis of electrospray ionization mass spectrum (ESI/MS) and there was an interesting finding that after the ion beam implantation the intensities of the components were different from the wild type strain.  相似文献   
4.
低能离子注入花生四烯酸产生菌诱变选育及其产业化研究   总被引:7,自引:0,他引:7  
利用低能离子束生物技术对花生四烯酸产生菌(Mortierella alpina,N7)进行诱变选育,并对获得的高产菌株进行了产业化研究。实验表明,在离子注入(10keV,3×1014N+/cm2)条件下,后代菌株离散程度明显高于自然分离。经连续诱变处理,最终获得一株花生四烯酸高产菌I49-N18。该菌株花生四烯酸得率高达4.66g/L,比对照N7菌株产量提高126.2%。通过微生物发酵法规模化生产花生四烯酸油脂,50吨发酵罐工业化生产,花生四烯酸产量平均达到5.11g/L。  相似文献   
5.
微生物发酵法生产花生四烯酸油脂   总被引:11,自引:3,他引:8  
研究了发酵法生产花生四烯酸油脂的过程 ,进行了 5 0t发酵罐工业化发酵 ,菌体收率达2 34g/ 10 0ml ,菌体内脂肪含量为 38 2 %。经分析油脂中含有花生四烯酸、γ 亚麻酸和亚油酸等多不饱和脂肪酸 ,其中花生四烯酸含量达到 5 1 75 %。  相似文献   
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