A feeding strategy for incorporation of canola derived medium-chain-length monomers into the PHA produced by wild-type Cupriavidus necator

作者：Rathinasabapathy Arthi; Ramsay Bruce A; Ramsay Juliana A^*; Perez Guevara Fermin

来源：World Journal of Microbiology and Biotechnology, 2014, 30(4): 1409-1416.

DOI：10.1007/s11274-013-1563-2

• Polyhydroxyalkanoates
• Cupriavidus necator
• Fed-batch fermentation
• Fructose
• Canola oil

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 mu 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 A degrees C), crystallinity (54 %), tensile stress (25.1 Mpa) and Young's modulus (698 Mpa) for a PHB standard decreased to 176 A degrees C, 52 %, 19.1 and 443 Mpa respectively for C. necator PHA produced in the 3-stage process.

• 出版日期2014-4