Wu Jiapeng, Tian Xingfang, Xu Xiaoning, Gu Xinyi, Kong Jian, Guo Tingting
State Key Laboratory of Microbial Technology, Shandong University, No. 72 Binhai Road, Qingdao 266237, P. R. China.
ACS Synth Biol. 2022 Apr 15;11(4):1568-1576. doi: 10.1021/acssynbio.1c00639. Epub 2022 Mar 15.
is a food-grade chassis for delivery of bioactive molecules to the intestinal mucosa , while its ability to produce lycopene for detoxification of reactive oxidative species (ROS) is not realized yet. Here, NZ9000 was engineered to synthesize lycopene by heterologous expression of a gene cluster in plasmids or chromosomes, yielding the recombinant strains NZ4 and NZ5 with 0.59 and 0.54 mg/L lycopene production, respectively. To reroute the pyruvate flux to lycopene, the main lactate dehydrogenase and α-acetolactate synthase pathways were sequentially disrupted. The resultant strains NZΔldh-1 and NZΔldhΔals-1 increased lycopene accumulation to 0.70 and 0.73 mg/L, respectively, while their biomasses were reduced by 12.42% and the intracellular NADH/NAD ratios increased by 3.05- and 2.10-fold. To increase the biomasses of these engineered strains, aerobic respiration was activated and tuned by the addition of exogenous heme and oxygen. As a result, the engineered strains partly recovered the growth and redox balance, yielding the lycopene levels of 0.91-1.09 mg/L. The engineered strain protected the intestinal epithelial cells NCM460 against HO challenge, with a 30.09% increase of cell survival and a 29.2% decrease of the intracellular ROS level compared with strain NZ9000 treatment. In summary, this work established the use of the engineered probiotic for lycopene production and prospected its potential in the prevention of intestinal oxidative damage.
是一种用于将生物活性分子递送至肠黏膜的食品级底盘，但其产生番茄红素用于清除活性氧化物种（ROS）的能力尚未实现。在此，通过在质粒或染色体中异源表达基因簇来改造NZ9000以合成番茄红素，分别产生番茄红素产量为0.59和0.54 mg/L的重组菌株NZ4和NZ5。为了将丙酮酸通量重新导向番茄红素，依次破坏了主要的乳酸脱氢酶和α-乙酰乳酸合酶途径。所得菌株NZΔldh-1和NZΔldhΔals-1的番茄红素积累分别增加到0.70和0.73 mg/L，而它们的生物量减少了12.42%，细胞内NADH/NAD比率分别增加了3.05倍和2.10倍。为了增加这些工程菌株的生物量，通过添加外源血红素和氧气来激活并调节有氧呼吸。结果，工程菌株部分恢复了生长和氧化还原平衡，番茄红素水平达到0.91 - 1.09 mg/L。与NZ9000菌株处理相比，工程菌株保护肠上皮细胞NCM460免受HO攻击，细胞存活率提高了30.09%，细胞内ROS水平降低了29.2%。总之，这项工作确立了工程益生菌用于生产番茄红素的用途，并展望了其在预防肠道氧化损伤方面的潜力。
