Optimization of Propagation Medium for Enhanced Polyhydroxyalkanoate Production by Pseudomonas oleovorans

Abstract

Polyhydroxyalkanoates (PHAs) represent a promising alternative to commercially used petroleum-based plastics. Pseudomonas oleovorans is a natural producer of medium-chain-length PHA (mcl-PHA) under cultivation conditions with nitrogen limitation and carbon excess. Two-step cultivation appears to be an efficient but more expensive method of PHA production. Therefore, the aim of this work was to prepare a minimal synthetic medium for maximum biomass yield and to optimize selected independent variables by response surface methodology (RSM). The highest biomass yield (1.71 ± 0.04 g/L) was achieved in the optimized medium containing 8.4 g/L glucose, 5.7 g/L sodium ammonium phosphate and 35.4 mM phosphate buffer. Under these conditions, both carbon and nitrogen sources were completely consumed after 48 h of the cultivation and the biomass yield was 1.7-fold higher than in the conventional medium recommended by the literature. This approach demonstrates the possibility of using two-stage PHA cultivation to obtain the maximum amount of biomass and PHA.

The Role of Bacterial Polyhydroalkanoate (PHA) in a Sustainable Future: A Review on the Biological Diversity

“…In Chmelová et al (2021), the effects of various culture medium components were studied through statistical design on the biomass production of P. oleovorans. This study allowed for the optimization of the production medium with minimal nutrients to increase PHA yielding [130]. Since 50% of PHA production cost is due to the cost of the carbon sources used in this process, some research focuses on investing in cheaper substrates including waste materials such as whey, starch, sugar-cane molasses waste, vegetable oils, and wastewater for the production of this polymer [131].…”