Ketocarotenoids are high-value pigments used commercially across multiple industrial sectors as colorants and supplements. Chemical synthesis using petrochemical-derived precursors remains the production method of choice. Aquaculture is an example where ketocarotenoid supplementation of feed is necessary to achieve product viability. The biosynthesis of ketocarotenoids, such as canthaxanthin, phoenicoxanthin, or astaxanthin in plants is rare. In the present study, complex engineering of the carotenoid pathway has been performed to produce high-value ketocarotenoids in tomato fruit (3.0 mg/g dry weight). The strategy adopted involved pathway extension beyond β-carotene through the expression of the β-carotene hydroxylase (CrtZ) and oxyxgenase (CrtW) from Brevundimonas sp. in tomato fruit, followed by β-carotene enhancement through the introgression of a lycopene β-cyclase (β-Cyc) allele from a Solanum galapagense background. Detailed biochemical analysis, carried out using chromatographic, UV/VIS, and MS approaches, identified the predominant carotenoid as fatty acid (C14:0 and C16:0) esters of phoenicoxanthin, present in the S stereoisomer configuration. Under a field-like environment with low resource input, scalability was shown with the potential to deliver 23 kg of ketocarotenoid/hectare. To illustrate the potential of this “generally recognized as safe” material with minimal, low-energy bioprocessing, two independent aquaculture trials were performed. The plant-based feeds developed were more efficient than the synthetic feed to color trout flesh (up to twofold increase in the retention of the main ketocarotenoids in the fish fillets). This achievement has the potential to create a new paradigm in the renewable production of economically competitive feed additives for the aquaculture industry and beyond.

中文翻译：

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番茄酮类胡萝卜素可持续生产的番茄工程及其在水产养殖饲料中的评价

酮类胡萝卜素是高价值颜料，广泛用于多个工业领域，用作着色剂和补充剂。使用石油化学衍生的前体进行化学合成仍然是选择的生产方法。水产养殖是必须补充饲料中酮类胡萝卜素以实现产品生存能力的一个例子。植物中角豆黄素，凤凰黄素或虾青素等酮类胡萝卜素的生物合成很少。在本研究中，已经对类胡萝卜素途径进行了复杂的工程设计，以在番茄果实（干重3.0 mg / g）中产生高价值的类胡萝卜素。该策略通过β胡萝卜素羟化酶的表达（通过参与通路延伸超出β胡萝卜素的CrtZ）和oxyxgenase（CrtW从）短波单胞sp。在番茄果实，随后β胡萝卜素增强通过番茄红素β环化酶（β-的基因渗入的Cyc）等位基因从茄属galapagense背景。详述生化分析，进行了使用色谱，UV / VIS，和MS方法，确定了主要的类胡萝卜素如脂肪酸（C14：0和C16：0）phoenicoxanthin的酯中，存在于小号立体异构体构型。在低资源投入的类似田间环境下，可扩展性已显示出可以输送23千克酮类胡萝卜素/公顷的潜力。为了说明这种“通常被认为是安全的”材料通过最少的低能耗生物处理的潜力，进行了两项独立的水产养殖试验。所开发的植物性饲料比色鳟鱼肉的合成饲料更有效（主要酮类胡萝卜素在鱼片中的保留量增加了两倍）。这一成就有可能在可再生生产中为水产养殖业及其他行业提供具有经济竞争力的饲料添加剂的新范例。