Rathinasabapathy Arthi, Ramsay Bruce A, Ramsay Juliana A, Pérez-Guevara Fermín
Chemical Engineering, Queen's University, Kingston, ON, K7L 3N6, Canada.
World J Microbiol Biotechnol. 2014 Apr;30(4):1409-16. doi: 10.1007/s11274-013-1563-2. Epub 2013 Nov 28.
The aim of this study was to increase the density of wild type Cupriavidus necator H16 biomass grown on fructose in order to produce sufficient copolymer of short-chain-length (scl) and medium-chain-length (mcl) polyhydroxyalkanoate (PHA) from canola oil for mechanical testing of the PHA. Initial batch cultivation on fructose was followed by exponential feeding of fructose at a predetermined μ to achieve 44.4 g biomass/l containing only 20 % w/w of polyhydroxybutyrate (PHB) with a Y(x/fructose) of 0.44 g/g. In a third stage, canola oil was added under N-limited conditions to produce 92 g/l of biomass with 48 % w/w scl-mcl PHA. Using known standards, the PHA composition was confirmed by GC-MS analysis as 99.81 % 3-hydroxybutyrate, 0.06 % 3-hydroxyvalerate, 0.09 % 3-hydroxyhexanoate and 0.04 % 3-hydroxyoctanoate. The melting temperature (179 °C), crystallinity (54 %), tensile stress (25.1 Mpa) and Young's modulus (698 Mpa) for a PHB standard decreased to 176 °C, 52 %, 19.1 and 443 Mpa respectively for C. necator PHA produced in the 3-stage process.
本研究的目的是提高在果糖上生长的野生型食酸丛毛单胞菌H16生物质的密度，以便从菜籽油中生产足够的短链长度（scl）和中链长度（mcl）聚羟基脂肪酸酯（PHA）共聚物，用于PHA的机械测试。首先在果糖上进行分批培养，然后以预定的μ指数补料果糖，以获得44.4 g生物质/升，其中仅含20% w/w的聚羟基丁酸酯（PHB），Y（x/果糖）为0.44 g/g。在第三阶段，在氮限制条件下添加菜籽油，以生产92 g/升含48% w/w scl-mcl PHA的生物质。使用已知标准，通过气相色谱-质谱分析确认PHA组成为99.81% 3-羟基丁酸酯、0.06% 3-羟基戊酸酯、0.09% 3-羟基己酸酯和0.04% 3-羟基辛酸酯。PHB标准品的熔点（179℃）、结晶度（54%）、拉伸应力（25.1 Mpa）和杨氏模量（698 Mpa），对于在三阶段过程中生产的食酸丛毛单胞菌PHA分别降至176℃、52%、19.1和443 Mpa。
