补加前体L-蛋氨酸对高密度发酵生产S-腺苷-L-蛋氨酸的影响

将高密度发酵技术成功应用于S-腺苷-L-蛋氨酸的生产。考察了补加前体L-蛋氨酸的量以及补加策略对酿酒酵母G14发酵生产S-腺苷-L-蛋氨酸的影响。实验发现补加前体L-蛋氨酸能明显促进S-腺苷-L-蛋氨酸的积累。同时还发现不同的补加策略对菌体浓度以及S-腺苷-L-蛋氨酸的产量和浓度有不同的影响。确定了补加L-蛋氨酸不应低于0.7g/10g菌体干重。比较了五种不同的补加前体L-蛋氨酸的方式。结果表明在菌体干重达到高密度的情况下(120g/L)补加前体L-蛋氨酸进行转化生产S-腺苷-L-蛋氨酸能达到比较好的效果一次性补加9g L-蛋氨酸,SAM的积累量在补加后的18h达到最高,为4.31g/L;采取流加方式补加L-蛋氨酸,流加速率为2g/h,共流加5h,流加结束28h后SAM达到最高积累量后者达到4.98g/L。两者最终的生物量均可达到130g/L以上。

Effect of Feeding Pre-L-methionine on High-cell-density Fermentation for S-adenosyl-L-methionine Production

The yield of S-adenosyl-L-methionine(SAM) by saccharomyces cerevisiae fermentation was affected by the strategy of feeding L-methionine. The effects that feeding strategies and the amount of precursor L-methionine had on the production of SAM by saccharomyces cerevisiae G14 were investigated. The results showed that feeding L-methionine could obviously improve the accumulation of SAM, and both the biomass and SAM yield relied heavily on different feeding strategies. In our work, it was found that total amount of L-methionine added should be no less than 0.7g per 10 grams of dry cell weight. Five different feeding strategies had been investigated in our experiment, and such comparison indicated that favorable results could be achieved as the biomass reached the status of high cell density (120g/L). If 9 grams of the precursor L-methionine was introduced once and for all, the accumulation of SAM reached maximum of 4.31g/L at the 18th hour after addition; if the precursor amino acid was fed at a rate of 2g/h in 5 h, maximum yield of 4.98g/L was achieved at the 28th hour after feeding. Thus high cell density fermentation can be successfully applied to SAM production by Saccharomyces cerevisiae with the consequence of over 130g/L of biomass gained using the above two strategies.