Ene Nicoleta, Soare Vladu Mariana-Gratiela, Lupescu Irina, Ionescu Ana-Despina, Vamanu Emanuel
Faculty of Biotechnologies, University of Agronomic Sciences and Veterinary Medicine, Mărăsti Blvd. 59, 011464 Bucharest, Romania.
National Institute for Chemical Pharmaceutical Research and Development-ICCF, Vitan Avenue 112, 031299 Bucharest, Romania.
Curr Pharm Biotechnol. 2022;23(8):1109-1117. doi: 10.2174/1389201022666210810114117.
Polyhydroxyalkanoates (PHAs) are bacteria-synthesized biopolymers under imbalanced growth conditions. These biopolymers are acknowledged as potential biomaterials for future applications because of their characteristics of biocompatibility and biodegradability, and ability to be produced rapidly, and strong functionality of mechanical resistance. This article aims to perform microbial fermentation using the Pseudomonas putida strain to identify the quantity of biopolymers, particularly of the medium-chain-length (mcl-PHA) polyhydroxyalkanoates, based on the type and quantity of the added precursors (glucose and fatty acids).
To understand the microbial interaction and the mechanism involved in PHA biosynthesis, several methods were employed and microbial biomass was obtained using the Pseudomonas putida strain capable of producing PHA. The polymer production by acetone extraction was analyzed using the Soxhlet method, while the biopolymer purification was done via the methanol-ethanol treatment, after which the biomass estimation was done through spectrophotometric analysis. This was followed by measuring the dry weight of the cells and quantification of the biopolymer produced using the gas chromatography method (GC).
The highest PHA yield was obtained using the octanoic (17 mL in 2000 mL medium) and hexanoic acids (14 mL in 2000 mL medium) as the precursors. As a result, the octanoic acid - octanoic acid, heptanoic acid - nonanoic acid, and octanoic acid - hexanoic acid were identified as the different precursors that supported the quantity of PHA obtained.
Among the 4 types of structurally related substrates, the Pseudomonas putida ICCF 319 strain showed a preference for the C8 sublayer for the biosynthesis of the elastomeric PHAs composed predominantly of more C8 monomers than the C6 and C10.
聚羟基脂肪酸酯（PHA）是细菌在生长条件不平衡时合成的生物聚合物。这些生物聚合物因其生物相容性和生物可降解性、快速生产能力以及强大的机械抗性功能，被公认为未来应用的潜在生物材料。本文旨在利用恶臭假单胞菌菌株进行微生物发酵，根据添加前体（葡萄糖和脂肪酸）的类型和数量，确定生物聚合物的数量，特别是中链长度（mcl-PHA）聚羟基脂肪酸酯的数量。
为了解PHA生物合成中涉及的微生物相互作用及其机制，采用了多种方法，并使用能够产生PHA的恶臭假单胞菌菌株获得微生物生物量。通过索氏提取法分析丙酮提取的聚合物产量，而生物聚合物的纯化则通过甲醇 - 乙醇处理进行，之后通过分光光度分析进行生物量估计。接着测量细胞的干重，并使用气相色谱法（GC）对产生的生物聚合物进行定量。
以辛酸（2000 mL培养基中17 mL）和己酸（2000 mL培养基中14 mL）作为前体时，获得了最高的PHA产量。结果表明，辛酸 - 辛酸、庚酸 - 壬酸和辛酸 - 己酸被确定为支持所获得的PHA数量的不同前体。
在4种结构相关的底物类型中，恶臭假单胞菌ICCF 319菌株在生物合成主要由比C6和C10更多的C8单体组成的弹性PHA时，对C8亚层表现出偏好。
