Enhanced yield of medium-chain-length polyhydroxyalkanoates from nonanoic acid by co-feeding glucose in carbon-limited, fed-batch culture

Abstract: Medium-chain-length polyhydroxyalkanoates (MCL-PHAs) were produced in carbon-limited, single-stage, fed-batch fermentations of Pseudomonas putida KT2440 by co-feeding nonanoic acid (NA) and glucose (G) to enhance the yield of PHA from NA. An exponential (μ =0.25h−1) followed by a linear feeding strategy at a NA:G ratio of 1:1 (w/w) achieved 71gl−1 biomass containing 56% PHA. Although the same overall PHA productivity (1.44gl−1 h−1) was obtained when NA alone was fed at the same specific growth rate, the overall yield of PHA from NA increased by 25% (0.66gPHAgNA−1 versus 0.53gg−1) with glucose co-feeding. Further increasing glucose in the feed (NA:G=1:1.5) resulted in a slightly higher yield (0.69gPHAgNA−1) but lower PHA content (48%) and productivity (1.16gl−1 h−1). There was very little change in the PHA composition. [Copyright &y& Elsevier]