Enhanced CO2 capture for photosynthetic lycopene production in engineered Rhodopseudomonas palustris, a purple nonsulfur bacterium
Enhanced CO2 capture for photosynthetic lycopene production in engineered Rhodopseudomonas palustris, a purple nonsulfur bacterium
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增强二氧化碳捕获，以促进沼泽红假单胞菌（一种紫色非硫细菌）光合番茄红素的生产
DOI：
10.1039/d2gc02467e
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发表时间：
2022-08-30
期刊：
影响因子：
9.8
通讯作者：
Yang, Jianming
中科院分区：
文献类型：
--
作者：
Li, Meijie;Xia, Qingqing;Yang, Jianming
番茄红素具有抗氧化、抗癌、抗炎等作用，在食品添加剂、药品、化妆品等领域有着广泛的应用。传统的植物提取番茄红素存在原料供应不稳定的问题，而化学合成番茄红素存在有毒化学试剂的残留，限制了番茄红素的质量。番茄红素在异养微生物中需要碳水化合物作为原料，并且在细胞代谢过程中不可避免地损失碳。在这里，我们报告直接番茄红素生产CO2光合自养细菌，Rhodoptera palustris，使用可持续的和碳中性的方法。采用代谢工程策略提高番茄红素在红球藻中的代谢通量。沼泽然后，对R.通过实验室适应性进化和添加甘油，沼泽化程度得到了很大的提高。首次证明了甘油同化和CO2固定的显著协同效应。在甘油降解途径中产生的NADH提供了CO2固定所需的电子，并且由甘油产生的二羟丙酮磷酸（DHAP）有利于核酮糖-1，5-二磷酸（Ru 1，5 P）再生，这是Calvin-Benson-Bassham（CBB）循环中的重要步骤。最终获得的工程菌RPLYC 45在CO2和甘油条件下番茄红素产量为283.2 mg g（-1）DCW，是出发菌株的87.4倍，是紫色非硫细菌（PNSB）中类异戊二烯产量最高的一株。我们的研究结果表明R. palustris被改造成一个微生物细胞工厂，使用二氧化碳和废甘油作为原料，这是一个比异养微生物生产番茄红素更可持续的过程。CO2固定率的提高有利于解决化石燃料大量利用带来的环境和不可持续性问题。甘油是生物柴油工业的副产品，利用甘油作为原料是生物柴油工业绿色化的一个有吸引力的选择。
Lycopene has been widely applied in the fields of food additives, drugs and cosmetics due to its anti-oxidative, anti-cancer, and anti-inflammatory activities. The traditional plant extraction of lycopene suffers from the unstable supply of raw materials, and for the chemical synthesis of lycopene, residues of toxic chemical reagents have limited the quality of lycopene. Lycopene in heterotrophic microorganisms suffers from the requirement of carbohydrates as feedstocks and inevitable carbon loss during cell metabolism. We here report direct lycopene production from CO2 in photoautotrophic bacteria, Rhodopseudomonas palustris, using sustainable and carbon-neutral methods. Metabolic engineering strategies were carried out to improve the metabolic flux directed toward lycopene in R. palustris. Then, the light-driven CO2 fixation efficiency of R. palustris was improved greatly by adaptive laboratory evolution and glycerol addition. The remarkable synergetic effect of glycerol assimilation and CO2 fixation was demonstrated for the first time. The NADH produced in the glycerol degradation pathway provided the electron required for CO2 fixation, and dihydroxyacetone phosphate (DHAP) produced from glycerol is beneficial for ribulose-1,5-bisphosphate (Ru1,5P) regeneration, an essential step in the Calvin-Benson-Bassham (CBB) cycle. The final engineered strain, RPLYC45, could accumulate a lycopene yield of 283.2 mg g(-1) DCW from CO2 and glycerol, which was 87.4 times greater than that of the original strain and represented the highest isoprenoid production using purple non-sulfur bacteria (PNSB). Our results demonstrated the large potential of R. palustris to be engineered as a microbial cell factory using CO2 and waste glycerol as feedstocks, a process more sustainable than the lycopene production in heterotrophic microorganisms. The enhanced CO2 fixation rate is beneficial for solving environmental and unsustainability problems caused by the extensive utilization of fossil fuels. The utilization of glycerol as a feedstock, an excessively available by-product of the biodiesel industry, is an attractive option to green up the biodiesel industry.