Department of Chemical Engineering, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea.
Department of Chemical Engineering, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea.
Int J Biol Macromol. 2021 Dec 1;192:289-297. doi: 10.1016/j.ijbiomac.2021.09.180. Epub 2021 Oct 4.
A cell retention culture of Paracoccus sp. LL1 was performed in a membrane bioreactor equipped with an internal ceramic filter module to reach high cell density and thus enhance the co-production of polyhydroxyalkanoates (PHA) and astaxanthin as growth-associated products. Cell retention culture results showed that PHA accumulation increased with increasing dry cell weight (DCW), giving rise to a maximum of 113 ± 0.92 g/L of DCW with 43.9 ± 0.91 g/L of PHA (38.8% of DCW) at 48 h. A significant increase in both intracellular and extracellular astaxanthin concentrations was also recorded during fermentation process achieving a maximum of 8.51 ± 0.20 and 10.2 ± 0.24 mg/L, respectively. Amounts of PHA and total astaxanthin produced by cell retention culture were 6.29 and 19.7-folds higher, respectively, than those recorded under batch cultivation. PHA and total astaxanthin productivities by cell retention culture also increased up to 0.914 g/L/h and 0.781 mg/L/h, respectively, which were 3.54 and 11.1-folds higher than those of batch culture. Based on gas chromatography, Fourier transform infrared spectroscopy, and H nuclear magnetic resonance spectroscopy, the extracted PHA was identified as a copolymer of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with a 3-hydroxyvalerate content of 3.78 mol%.
采用内置陶瓷膜过滤器的膜生物反应器对 Paracoccus sp. LL1 进行细胞截留培养，以达到高细胞密度，从而增强聚羟基烷酸（PHA）和虾青素作为生长相关产物的共生产。细胞截留培养结果表明，PHA 积累随干细胞重量（DCW）的增加而增加，在 48 小时时达到最高的 113 ± 0.92 g/L DCW，其中 PHA 为 43.9 ± 0.91 g/L（占 DCW 的 38.8%）。发酵过程中还记录到细胞内和细胞外虾青素浓度的显著增加，分别达到最高的 8.51 ± 0.20 和 10.2 ± 0.24 mg/L。细胞截留培养产生的 PHA 和总虾青素分别比分批培养高出 6.29 和 19.7 倍。细胞截留培养的 PHA 和总虾青素的比生产力也分别增加到 0.914 g/L/h 和 0.781 mg/L/h，分别比分批培养高出 3.54 和 11.1 倍。通过气相色谱、傅里叶变换红外光谱和 H 核磁共振光谱对提取的 PHA 进行鉴定，其为聚（3-羟基丁酸-co-3-羟基戊酸）共聚物，其中 3-羟基戊酸含量为 3.78 mol%。
