Jiang Yang, Mikova Gizela, Kleerebezem Robbert, van der Wielen Luuk Am, Cuellar Maria C
Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628 BC Delft, The Netherlands.
Polymer Technology Group Eindhoven BV, De Lismortel 31, 5612 AR Eindhoven, The Netherlands.
AMB Express. 2015 Jan 24;5(1):5. doi: 10.1186/s13568-015-0096-5. eCollection 2015 Dec.
This study focused on investigating the feasibility of purifying polyhydroxybutyrate (PHB) from mixed culture biomass by alkaline-based chemical treatment. The PHB-containing biomass was enriched on acetate under non-sterile conditions. Alkaline treatment (0.2 M NaOH) together with surfactant SDS (0.2 w/v% SDS) could reach 99% purity, with more than 90% recovery. The lost PHB could be mostly attributed to PHB hydrolysis during the alkaline treatment. PHB hydrolysis could be moderated by increasing the crystallinity of the PHB granules, for example, by biomass pretreatment (e.g. freezing or lyophilization) or by effective cell lysis (e.g. adjusting alkali concentration). The suitability of the purified PHB by alkaline treatment for polymer applications was evaluated by molecular weight and thermal stability. A solvent based purification method was also performed for comparison purposes. As result, PHB produced by mixed enriched cultures was found suitable for thermoplastic applications when purified by the solvent method. While the alkaline method resulted in purity, recovery yield and molecular weight comparable to values reported in literature for PHB produced by pure cultures, it was found unsuitable for thermoplastic applications. Given the potential low cost and favorable environmental impact of this method, it is expected that PHB purified by alkaline method may be suitable for other non-thermal polymer applications, and as a platform chemical.
本研究聚焦于通过基于碱的化学处理从混合培养生物量中纯化聚羟基丁酸酯（PHB）的可行性。含PHB的生物量在非无菌条件下以乙酸盐为底物进行富集培养。碱处理（0.2 M NaOH）与表面活性剂十二烷基硫酸钠（SDS，0.2 w/v%）相结合可使纯度达到99%，回收率超过90%。损失的PHB主要归因于碱处理过程中的PHB水解。可通过提高PHB颗粒的结晶度来减缓PHB水解，例如通过生物量预处理（如冷冻或冻干）或有效的细胞裂解（如调整碱浓度）。通过分子量和热稳定性评估了经碱处理纯化的PHB在聚合物应用中的适用性。还进行了一种基于溶剂的纯化方法用于比较。结果发现，通过溶剂法纯化时，混合富集培养产生的PHB适用于热塑性应用。虽然碱法得到的纯度、回收率和分子量与文献中报道的纯培养产生的PHB的值相当，但发现其不适用于热塑性应用。鉴于该方法潜在的低成本和良好的环境影响，预计通过碱法纯化的PHB可能适用于其他非热聚合物应用，并作为一种平台化学品。
