Abstract：
While the expansion of the erythritol production industry has resulted in unprecedented production of yeast cells, it also suffers from a lack of effective utilization. β-Carotene is a value-added compound that can be synthesized by engineered Yarrowia lipolytica. Here, we first evaluated the production performance of erythritol-producing yeast strains under two different morphologies and then successfully constructed a chassis with yeast-like morphology by deleting Mhy1 and Cla4 genes. Subsequently, β-carotene synthesis pathway genes, CarRA and CarB from Blakeslea trispora, were introduced to construct the β-carotene and erythritol coproducing Y. lipolytica strain ylmcc. The rate-limiting genes GGS1 and tHMG1 were overexpressed to increase the β-carotene yield by 45.32-fold compared with the strain ylmcc. However, increased β-carotene accumulation led to prolonged fermentation time; therefore, transporter engineering through overexpression of YTH1 and YTH3 genes was used to alleviate fermentation delays. Using batch fermentation in a 3 L bioreactor, this engineered Y. lipolytica strain produced erythritol with production, yield, and productivity values of 171 g/L, 0.56 g/g glucose, and 2.38 g/(L·h), respectively, with a concomitant β-carotene yield of 47.36 ± 0.06 mg/g DCW. The approach presented here improves the value of erythritol-producing cells and offers a low-cost technique to obtain hydrophobic terpenoids.
摘要：
虽然赤藓糖醇生产行业的扩张导致了前所未有的酵母细胞生产，它还缺乏有效利用。β-胡萝卜素是一种增值化合物，可以通过工程Yarrowialipolytica合成。这里,我们首先评估了在两种不同形态下生产赤藓糖醇的酵母菌株的生产性能，然后通过删除Mhy1和Cla4基因成功构建了具有酵母样形态的底盘。随后，β-胡萝卜素合成途径基因,来自Blakesleatrispora的CarRA和CarB,引入β-胡萝卜素和赤藓糖醇共同生产Y.Lipolytica菌株ylmcc。过表达限速基因GGS1和tHMG1，与菌株ylmcc相比，β-胡萝卜素的产量提高了45.32倍。然而,β-胡萝卜素积累的增加导致发酵时间延长；因此，通过过表达YTH1和YTH3基因的转运蛋白工程用于缓解发酵延迟。在3L生物反应器中使用分批发酵，这种工程化的Y.Lipolytica菌株产生赤藓糖醇，产量，和171g/L的生产率值，0.56g/g葡萄糖，和2.38g/（L·h），分别,伴随的β-胡萝卜素产量为47.36±0.06mg/gDCW。本文提出的方法提高了赤藓糖醇生产细胞的价值，并提供了一种低成本的技术来获得疏水性萜类化合物。
