Synergistic experimental and computational approach identifies novel strategies for polyhydroxybutyrate overproduction
Synergistic experimental and computational approach identifies novel strategies for polyhydroxybutyrate overproduction
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DOI：
10.1016/j.ymben.2021.08.008
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发表时间：
2021-09-03
影响因子：
8.4
通讯作者：
Saha, Rajib
中科院分区：
文献类型：
--
作者：
Alsiyabi, Adil;Brown, Brandi;Saha, Rajib
聚羟基丁酸酯（PHB）是一种由细菌产生的可持续生物塑料，是传统塑料的潜在替代品。这项研究提供了一个综合的实验和计算建模方法来破译控制PHB生产的代谢因素，并提供了工程设计策略，以提高生产。在代谢稳健的Rhodopyramidpalustris CGA 009中，生长在富含碳和电子的木质素分解产物p-香豆酸盐（C9 H8 O3）上时，与乙酸盐（C2 H3 NaO 2）几乎没有PHB滴度相比，PHB产量显着增加。当生长在松柏醇（C10 H12 O3）上时，最大产率没有进一步提高，但是对PHB曲线的比较表明，松柏醇的较高碳含量导致较高的PHB生产速率。结合实验结果表明，细胞质空间可能是最大的PHB滴度的限制因素。为了获得一个系统级的理解的因素驱动的聚羟基丁酸产量，模型驱动的调查进行。该模型产生了几种工程设计策略，包括利用绕过硫解酶反应（phaA）的还原的高分子量底物。基于这些策略，预测并随后验证了丁酸盐的利用以产生PHB。模型分析还解释了为什么氮饥饿对PHB生产不是必不可少的，并揭示了可再生的和丰富的木质素芳烃是PHB生产的理想候选物。最重要的是，所得到的设计规则的一般性允许它们被应用于具有类似代谢特征的任何产生PHB的微生物。
Polyhydroxybutyrate (PHB) is a sustainable bioplastic produced by bacteria that is a potential replacement for conventional plastics. This study delivers an integrated experimental and computational modeling approach to decipher metabolic factors controlling PHB production and offers engineering design strategies to boost production. In the metabolically robust Rhodopseudomonas palustris CGA009, PHB production significantly increased when grown on the carbon- and electron-rich lignin breakdown product p-coumarate (C9H8O3) compared to virtually no PHB titer from acetate (C2H3NaO2). The maximum yield did not improve further when grown on coniferyl alcohol (C10H12O3), but comparison of the PHB profiles showed that coniferyl alcohol's higher carbon content resulted in a higher rate of PHB production. Combined experimental results revealed that cytoplasmic space may be a limiting factor for maximum PHB titer. In order to obtain a systems-level understanding of factors driving PHB yield, a model-driven investigation was performed. The model yielded several engineering design strategies including utilizing reduced, high molecular weight substrates that bypass the thiolase reaction (phaA). Based on these strategies, utilization of butyrate was predicted and subsequently validated to produce PHB. Model analysis also explained why nitrogen starvation was not essential for PHB production and revealed that renewable and abundant lignin aromatics are ideal candidates for PHB production. Most importantly, the generality of the derived design rules allows them to be applied to any PHB-producing microbe with similar metabolic features.