Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Post. 510-3, Cuernavaca, 62250, Morelos, México.
Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México.
J Biotechnol. 2017 Oct 10;259:50-55. doi: 10.1016/j.jbiotec.2017.08.016. Epub 2017 Aug 19.
Poly-3-hydroxybutyrate (P3HB) is a biopolymer produced by Azotobacter vinelandii. The physicochemical properties and applications of P3HB are strongly influenced by its weight-average molecular mass (Mw), and in A. vinelandii, it could be influenced by the culture conditions. The aim of this study was to evaluate the effect of the P3HB content of the inoculum on the Mw of the polymer produced by A. vinelandii OP in bioreactor cultures. A. vinelandii cells containing 20, 50 and 70% of P3HB were used as inoculum. The P3HB content in the inoculum affected the volumetric P3HB productivity (q) and the Mw of P3HB. Those cultures inoculated with cells containing 20% of P3HB, achieved the highest q (0.17±0.018gLh); whereas a P3HB content of 70% was reflected as a low q (0.021±0.002gLh). On the other hand, using an inoculum with 70% of polymer content, the Mw of the biopolymer remained stable at values close to 3200kDa; whereas, when an inoculum with 20% of P3HB was used, the Mw decreased drastically during early stages of cultivation. These results show that manipulating the P3HB content of the inoculum is possible to produce biopolymers with a suitable Mw.
聚 3-羟基丁酸酯（P3HB）是由土壤固氮菌产生的一种生物聚合物。P3HB 的物理化学性质和应用强烈地受到其重均分子量（Mw）的影响，而在土壤固氮菌中，它可能会受到培养条件的影响。本研究旨在评估接种物中 P3HB 含量对土壤固氮菌 OP 在生物反应器培养中产生的聚合物 Mw 的影响。使用含有 20%、50%和 70% P3HB 的土壤固氮菌细胞作为接种物。接种物中 P3HB 含量影响 P3HB 的容积产率（q）和 Mw。用含有 20% P3HB 的细胞接种的培养物达到了最高的 q（0.17±0.018gLh）；而 P3HB 含量为 70%则反映出 q 较低（0.021±0.002gLh）。另一方面，使用含有 70%聚合物含量的接种物，生物聚合物的 Mw 保持稳定，接近 3200kDa；而当使用含有 20% P3HB 的接种物时，在培养的早期阶段 Mw 急剧下降。这些结果表明，通过操纵接种物中 P3HB 的含量，可以生产出具有合适 Mw 的生物聚合物。
