Plant-based recombinant protein production systems are powerful tools that can be used instead of microbial and animal cell culture systems. The aim of this study was to establish a stable brazzein production system from carrot cell suspension using bioreactor. Using Agrobacterium-mediated transformation (stress-inducible SWPA2 promoter and brazzein gene), three transgenic lines (TC1, 11, 12) were generated. During the TC12 culture period, cell proliferation increased rapidly up to 15 days, and the maximum cell division rate (log phase) was reached after 6 days of culture. Fresh weight peaked at day 18, 3.8-fold (7.6 g 100 mL⁻¹) higher than on day 1, and gene expression was tenfold higher on day 27 than on day 0. The brazzein-encoding gene was also analyzed after treatment with various stress factors for increase of brazzein gene expression, and abscisic acid (ABA) and hydrogen peroxide (H₂O₂) proved most effective. In particular, the gene expression was enhanced 2.5-fold with 220 μM H₂O₂ and 2.8-fold with 50 μM ABA, compared with controls. Transgenic cells were then transferred to various types of air-lift bioreactor, and the column bioreactor achieved a higher biomass (238.9 g L⁻¹) than cone and balloon bioreactors. These results demonstrate an efficient protein production system for brazzein using an air-lift bioreactor that may be suitable for the use in the food industry.

中文翻译：

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通过非生物胁迫和生物反应器培养系统增加了巴西精蛋白的表达，以生产甜蛋白，巴西精蛋白

基于植物的重组蛋白生产系统是功能强大的工具，可代替微生物和动物细胞培养系统使用。这项研究的目的是使用生物反应器从胡萝卜细胞悬液中建立稳定的巴西青素生产系统。使用农杆菌介导的转化（应激诱导的SWPA2启动子和brazzein基因），产生了三个转基因品系（TC1、11、12）。在TC12培养期间，直至15天，细胞增殖迅速增加，培养6天后达到最大细胞分裂率（对数期）。鲜重在第18天达到峰值，为3.8倍（7.6 g 100 mL ^-1）高于第1天，而第27天的基因表达则比第0天高十倍。还在各种应激因素处理后增加了巴西青素编码基因的表达，分析了巴西青素基因表达，脱落酸（ABA）和氢的增加过氧化物（H ₂ O ₂）被证明是最有效的。特别是，与对照相比，基因表达在220μMH ₂ O ₂下增强了2.5倍，在50μMABA下增强了2.8倍。然后将转基因细胞转移到各种类型的气升式生物反应器中，柱式生物反应器获得了更高的生物量（238.9 g L ^-1），而不是锥形和气囊生物反应器。这些结果证明了使用气举式生物反应器的用于巴西精的有效蛋白质生产系统，该系统可能适用于食品工业。