Abstract

Because of its application potential and biodegradability, poly(3-hydroxybutyrate-co-3-hydroxyvalerate;PHBV), a member of the polyhydroxyalkanoates (PHA) biopolymer family, is one of the most extensively studied PHA. High PHBV productivity with a significant amount of hydroxyvalerate (HV) content is very appealing for commercial scale production. The goal of this study was to investigate the efficiency of various defined limitation strategies, namely nitrogen, phosphorus, and oxygen-limitation, for high yield PHBV production by Cupriavidus necator H16 with increased HV unit using waste frying vegetable oil (WFO) and propionic acid (PA) in a high cell density culture (5 L bioreactor). With optimized WFO and PA feeding, highest PHBV harvest (121.7 ± 2.59 g/L; HV 13.9 ± 0.44% (w/w)) and volumetric productivity (2.03 ± 0.04 gPHBV/L·h) were obtained in oxygen-limited operation, while highest HV content (19.8 ± 0.28 wt%) and yield coefficient (0.43 ± 0.017 gHV/gPA) were observed during phosphorus-limited cultivation. Although nitrogen limitation is widely applied in the production of PHA, nitrogen-limited cultivation had the lowest cell dry matter, PHBV production, volumetric productivity, oil-to-HB and PA-to-HV yield coefficients for the given conditions. The results of the present study demonstrate the highest PHBV yield together with the highest HV content using WFO as main carbon source and PA as the HV precursor ever reported in the literature.

摘要

由于其应用潜力和生物降解性，聚（3-羟基丁酸酯-co-3-羟基戊酸酯；PHBV）作为聚羟基脂肪酸酯 (PHA) 生物聚合物家族的一员，是研究最广泛的 PHA 之一。具有大量羟基戊酸 (HV) 含量的高 PHBV 生产率对于商业规模生产非常有吸引力。本研究的目的是研究各种确定的限制策略（即氮、磷和氧限制）对Cupriavidus necator高产 PHBV 生产的效率H16 增加了 HV 单元，在高细胞密度培养物（5 L 生物反应器）中使用废弃的油炸植物油 (WFO) 和丙酸 (PA)。通过优化 WFO 和 PA 进料，在限氧操作中获得最高 PHBV 收获（121.7 ± 2.59 g/L；HV 13.9 ± 0.44% (w/w)）和体积生产率（2.03 ± 0.04 gPHBV/L·h），而在限磷栽培期间观察到最高的 HV 含量 (19.8 ± 0.28 wt%) 和产量系数 (0.43 ± 0.017 gHV/gPA)。尽管限氮广泛应用于 PHA 的生产，但限氮培养在给定条件下具有最低的细胞干物质、PHBV 产量、体积生产率、油对 HB 和 PA 对 HV 的产率系数。