氧化乐果降解菌株发酵培养基碳氮源优化的研究

Study on Optimizing the Carbon and Nitrogen Source of Fermention Medium of Folimat Degradation Strain

为确定氧化乐果降解菌株L-3发酵培养基碳源和氮源的最优配比,在质量浓度为1.0mg/mL的氧化乐果降解菌株的基础发酵培养基中,添加不同的碳源和氮源,选出适合菌株生长的最佳碳源和氮源,采用正交试验设计,优化出碳氮源的最佳配比,并进一步测定菌株L-3的生长情况和对氧化乐果的降解效果。结果表明,菌株L-3发酵培养基中最佳的碳源和氮源分别为蔗糖和NH4NO3;最佳的发酵条件为A3B2C3碳源质量浓度0.6g/L,氮源质量浓度0.5g/L,pH值7.0;最适的碳氮质量比为6∶5;菌株L-3在第3天达到生长高峰期,第4天达到降解高峰期,其降解氧化乐果的能力高达86%。优化后的菌种培养基更利于菌体生长,提高了氧化乐果的降解效果。

For ascertaining the optimization matching of C/N of folimat L-3 strains in the fermentation medium, it needed to add to different carbon source （glucose／cane sugar／lactosekfructose／amidulin） and different nitrogen source （（NH4）2SO4／ NH4NO3／urea／folimat） -at foundation fermention medium with the 1.0 mg/mL concentration of folimat, by which, the best carbon source and nitrogen source can be found out. One step further, the best matching of carbon source and nitrogen source were optimized by adopting orthogonal experiment. After the optimization, the growth condition of L-3 strains and the degradation for the folimat were tested. The results indicated that the best carbon source and nitrogen source were cane sugar and NH4NO3 in the fermention medium; the best fermentation condition were： A3B2C3, C 0.6 g/L, N 0.5 g/L, pH7.0; the optimal proportion of carbon and nitrogen were 6 ： 5 ; the L-3 strains the growth fastigium at the third day can be achieved, the degradation fastigium of folimat was at the forth day, the degradation ratio reached up to 86%. The optimized medium was in favour of the growing of thallus, the degradation ratio furthermore of folimat were increased.