Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Northeast Forestry University, Ministry of Education, Harbin 150040, China; College of Life Sciences, Northeast Forestry University, Harbin 150040, China.
College of Life Sciences, Northeast Forestry University, Harbin 150040, China.
Int J Biol Macromol. 2021 Sep 30;187:675-682. doi: 10.1016/j.ijbiomac.2021.07.137. Epub 2021 Jul 24.
Waste straw bio-transformation of high value-added macromolecule polyhydroxyalkanoates (PHAs) was significance to environmental sustainable development. As a member of the PHA family, poly-β-hydroxybutyrate (PHB) could be synthesized by Halomonas elongata A1 with maximal yields of 22.8% and 11.8% of bacterial weights using glucose and carboxymethyl cellulose as carbon sources, respectively. To improve PHB production, we generated three recombinant strains, the H. elongata P2 with highest PHB biosynthesis ability. When wheat straw, mixed substrate and oleic acid were individually used as single carbon source, the maximal PHA polymer accumulation in the H. elongata P2 reached 5.2%, 16.5% and 27.5%, respectively, after 84 h of cultivation. This hardness, toughness and crystallization properties of the PHA macromolecule altered dependent on starting substrates, when analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). In terms of the hardness and roughness, the PHA produced from mixed substrates was much softer than that from wheat straw but harder than that from oleic acid. The long-chain carbon improved the softness and strength of the produced PHA. Our data indicate that economical substrates, such as straw and waste oil, can be used in the synthesis of multi-functional plastic products with biodegradable properties.
利用农业废弃物秸秆生物转化生产具有高附加值的高分子量聚羟基烷酸酯（PHA）对于环境的可持续发展具有重要意义。作为 PHA 家族的一员，盐单胞菌（Halomonas elongata）A1 可以利用葡萄糖和羧甲基纤维素作为碳源分别合成出最大产率为 22.8%和 11.8%菌体干重的聚-β-羟基丁酸（PHB）。为了提高 PHB 的产量，我们构建了三个重组菌株，其中 H. elongata P2 具有最高的 PHB 生物合成能力。当小麦秸秆、混合底物和油酸分别作为单一碳源时，H. elongata P2 在 84 h 培养后最大 PHA 聚合物积累量分别达到 5.2%、16.5%和 27.5%。通过扫描电子显微镜（SEM）、傅里叶变换红外光谱（FTIR）和差示扫描量热法（DSC）分析发现，这些高分子量 PHA 的形成依赖于起始底物，其力学性能、韧性和结晶性能均发生改变。从硬度和粗糙度来看，混合底物合成的 PHA 比小麦秸秆合成的 PHA 更软，但比油酸合成的 PHA 更硬。长链碳改善了所合成 PHA 的柔韧性和强度。我们的数据表明，经济实用的底物，如秸秆和废油，可用于合成具有生物降解性能的多功能塑料产品。
