Hammami Khouloud, Souii Amal, Hassen Wafa, Chouchane Habib, Masmoudi Ahmed Slaheddine, Cherif Ameur, Souissi Yasmine, Neifar Mohamed
BVBGR-LR11ES31, Higher Institute of Biotechnology of Sidi Thabet (ISBST), University of Manouba, Ariana, Tunisia.
Research Unit of Analysis and Process Applied On the Environmental-APAE UR17ES32, Higher Institute of Applied Sciences and Technology Mahdia "ISSAT", University of Monastir, 5100, Mahdia, Tunisia.
Curr Microbiol. 2025 Apr 3;82(5):227. doi: 10.1007/s00284-025-04218-w.
In this study, a seven-factor Hoke experimental design and the response surface methodology were used to optimize the fermentation conditions for the maximum polyhydroxyalkanoates (PHA) yield using polyurethane plastic waste (PUPW) as a source of carbon and energy for the microbial growth and biobased polyester production. The highest PHA yield (0.80 g/L ± 0.01) was obtained under a pH of 8; a temperature of 35 °C; a NaCl concentration of 5%; a PUPW concentration of 1%; an inoculum size of 15%, a monoculture of Pseudomonas rhizophila S211; and an incubation time of 6 days. The response values predicted by the Hoke design model at each combination of factor levels aligned with the experimental results, and the analysis of variance demonstrated the predictability and accuracy of the postulated model. In addition to the experimental evidences, P. rhizophila genome was explored to predict the PUPW-degrading enzymes and the associated protein secretion systems. Moreover, physicochemical properties, phylogenetic analysis, and 3D structure of S211 LipA2 polyurethanase were elucidated through an in-silico approach. Taken all together, integrated experimental tests and computational modeling suggest that P. rhizophila S211 has the necessary enzymatic machinery to effectively convert the non-biodegradable PUPW into PHA bioplastics.
在本研究中，采用七因素霍克实验设计和响应面方法，以聚氨酯塑料废料（PUPW）作为微生物生长和生物基聚酯生产的碳源和能源，优化发酵条件以实现聚羟基脂肪酸酯（PHA）的最大产量。在pH值为8、温度为35℃、NaCl浓度为5%、PUPW浓度为1%、接种量为15%、单一培养的嗜根假单胞菌S211以及培养时间为6天的条件下，获得了最高的PHA产量（0.80 g/L±0.01）。霍克设计模型在各因素水平组合下预测的响应值与实验结果相符，方差分析证明了所假设模型的可预测性和准确性。除了实验证据外，还对嗜根假单胞菌的基因组进行了探索，以预测PUPW降解酶和相关的蛋白质分泌系统。此外，通过计算机模拟方法阐明了S211 LipA2聚氨酯酶的物理化学性质、系统发育分析和三维结构。综合来看，综合实验测试和计算建模表明，嗜根假单胞菌S211具备将不可生物降解的PUPW有效转化为PHA生物塑料的必要酶机制。
