稀土元素对L-酪氨酸发酵的影响研究

Study on Effect of Rare Earth Elements on Fermentation of L-Tyrosine

目前工业上主要采取微生物发酵法生产L-酪氨酸,此工艺存在生产周期长、糖酸转化率低等问题。因此,该研究以发酵过程中菌体量、L-酪氨酸产量、糖酸转换率以及耗糖速率为指标,通过单因素实验和正交实验探究La^(3+)、Ce^(3+)、Nd^(3+)对L-酪氨酸发酵的影响并最终确定了稀土元素的添加组合,提高了菌体的活力,缩短了延滞期,延长了产酸高峰期。实验结果表明,向L-酪氨酸发酵培养基中添加80 mg/L La^(3+)、2 mg/L Ce^(3+)、0.3 mg/L Nd^(3+)对发酵有利。发酵耗时35 h,缩短了2.2%;最高菌体量达到80.3,提升了10.8%;产酸量达到55.7 g/L,提升了9.7%;糖酸转化率为23.4%,提升了6.4%。验证了添加稀土元素的可行性,为L-酪氨酸大规模工业化生产提供了依据。

At present,microbial fermentation method is the main method to produce L-tyrosine in industry,which has problems such as long production cycle and low sugar-acid conversion rate.Therefore,in this study,with the bacterial biomass,L-tyrosine yield,sugar-acid conversion rate and sugar consumption rate in the fermentation process as the indexes,the effects of La^(3+),Ce^(3+)and Nd^(3+)on the fermentation of L-tyrosine is explored through single factor experiment and orthogonal experiment.Finally,the addition combination of rare earth elements is determined,which has improved the bacterial vitality,shortened the lag period and extended the peak period of acid production.The results show that adding 80 mg/L La^(3+),2 mg/L Ce^(3+)and 0.3 mg/L Nd^(3+)into L-tyrosine fermentation medium is beneficial to fermentation.Fermentation time is 35 h,which is shortened by 2.2%.The maximum bacterial biomass reaches 80.3,increasing by 10.8%.Acid yield reaches 55.7 g/L,increasing by 9.7%.The sugar-acid conversion rate is 23.4%,increasing by 6.4%.The feasibility of adding rare earth elements is verified,which has provided a basis for large-scale industrial production of L-tyrosine.