Department of Civil and Environmental Engineering, Stanford University, Stanford, CA 94305-4020, USA.
Department of Chemistry, Stanford University, Stanford, CA 94305-4401, USA.
Bioresour Technol. 2014 Oct;170:167-174. doi: 10.1016/j.biortech.2014.07.105. Epub 2014 Aug 4.
An abiotic-biotic strategy for recycling of polyhydroxyalkanoates (PHAs) is evaluated. Base-catalyzed PHA depolymerization yields hydroxyacids, such as 3-hydroxybutyrate (3HB), and alkenoates, such as crotonate; catalytic thermal depolymerization yields alkenoates. Cyclic pulse addition of 3HB to triplicate bioreactors selected for an enrichment of Comamonas, Brachymonas and Acinetobacter. After each pulse, poly(3-hydroxybutyrate) (P3HB) transiently appeared: accumulation of P3HB correlated with hydrolysis of polyphosphate; consumption of P3HB correlated with polyphosphate synthesis. Cells removed from the cyclic regime and incubated with 3HB under nitrogen-limited conditions produced P3HB (molecular weight>1,000,000Da) at 50% of the cell dry weight (<8h). P3HB also resulted from incubation with acetate, crotonate, or a mixture of hydrolytic depolymerization products. Poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) resulted from incubation with valerate or 2-pentenoate. A recycling strategy where abiotic depolymerization of waste PHAs yields feedstock for customized PHA re-synthesis appears feasible, without the need for energy-intensive feedstock purification.
评估了一种用于回收聚羟基烷酸酯 (PHA) 的非生物-生物策略。碱性催化剂引发的 PHA 解聚生成羟基酸，如 3-羟基丁酸 (3HB) 和烯酸，如巴豆酸；催化热解聚生成烯酸。将 3HB 周期性脉冲添加到选择用于富集 Comamonas、Brachymonas 和 Acinetobacter 的三重复生物反应器中。每次脉冲后，聚(3-羟基丁酸) (P3HB) 都会短暂出现：P3HB 的积累与多磷酸盐的水解相关；P3HB 的消耗与多磷酸盐的合成相关。从循环状态中取出的细胞并在氮限制条件下用 3HB 孵育会以细胞干重的 50%（<8h）生成 P3HB（分子量>1,000,000Da）。用乙酸、巴豆酸或水解解聚产物的混合物孵育也会生成 P3HB。用戊酸或 2-戊烯酸孵育会生成聚(3-羟基丁酸-co-3-羟基戊酸) (PHBV)。一种非生物解聚废 PHAs 以生成用于定制 PHA 再合成的原料的回收策略似乎是可行的，而无需进行能源密集型的原料纯化。
