Background

Bio-based nylon is synthesized from putrescine, cadaverine, or 4-amino butyric acid through decarboxylases by a green process aimed toward a renewable nylon market. Thus, quantifying the activity of the key enzyme decarboxylase with precision and efficiency, is critical for the development of the system. Moreover, one molecular carbon dioxide releasing from the reaction should be considered in greenhouse gas effect.

Methods

We established a new assay based on pH value decline by using different alkaline solution to absorb and capture the CO₂ released during decarboxylation. The pH change is corresponding to decarboxylase activity. On the other hand, carbonic anhydrase (CA), phosphoribulokinase (PRK) and ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) genes involved in CO₂ respiration, were applied with lysine decarboxylase (CadA) for simultaneous production of cadaverine and recovery of CO₂.

Significant Findings

The correlation between lysine, glutamate, or arginine conversion and its pH changes in different decarboxylases was successfully determined using a numerical equation with a high regression value (R² > 0.95). For cascade enzymatic reaction, RuBisCo was hardly co-expressed with CadA. Therefore, the strain with CadA and CA resulted in the release of the least amount of CO₂ among all the varieties, reaching the best CO₂ assimilation capability of −4.95 g-CO₂/g-dry cell weight (DCW) and an acceptable DAP of 15.67 g/L. This illustrates a new trend of bio-mitigation of CO₂ with simultaneous production of a variety of desirable chemicals.

中文翻译：

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精确测量脱羧酶和应用级联酶，用于同时生产尸胺和二氧化碳回收

背景

生物基尼龙是由腐胺、尸胺或 4-氨基丁酸通过脱羧酶通过绿色工艺合成的，旨在面向可再生尼龙市场。因此，精确高效地量化关键酶脱羧酶的活性对于系统的开发至关重要。此外，在温室气体效应中应考虑从反应中释放的一分子二氧化碳。

方法

我们通过使用不同的碱性溶液来吸收和捕获脱羧过程中释放的 CO _{2 ，}建立了一种基于 pH 值下降的新测定方法。pH 变化对应于脱羧酶活性。另一方面，参与 CO ₂呼吸的碳酸酐酶 (CA)、磷酸核糖激酶 (PRK) 和核酮糖-1,5-二磷酸羧化酶/加氧酶 (RuBisCo) 基因与赖氨酸脱羧酶 (CadA) 一起应用于同时生产尸胺和CO _{2 的}回收。

重要发现

使用具有高回归值 (R ² > 0.95)的数值方程成功确定了赖氨酸、谷氨酸或精氨酸转化与其在不同脱羧酶中的 pH 变化之间的相关性。对于级联酶促反应，RuBisCo 几乎不与 CadA 共表达。因此，具有CadA和CA的菌株在所有品种中释放出最少的CO ₂，达到最佳的CO ₂同化能力-4.95 g-CO ₂ /g-干细胞重量（DCW）和可接受的DAP 为 15.67 克/升。这说明了生物缓解 CO ₂的新趋势，同时生产各种理想的化学品。