Tailoring the HHx monomer content of P(HB- co-HHx) by flexible substrate compositions: scale-up from deep-well-plates to laboratory bioreactor cultivations

Lara Santolin; Isabel Thiele; Peter Neubauer; Sebastian L Riedel

doi:10.3389/fbioe.2023.1081072

Tailoring the HHx monomer content of P(HB- co-HHx) by flexible substrate compositions: scale-up from deep-well-plates to laboratory bioreactor cultivations

Front Bioeng Biotechnol. 2023 May 2:11:1081072. doi: 10.3389/fbioe.2023.1081072. eCollection 2023.

Authors

Lara Santolin¹, Isabel Thiele¹, Peter Neubauer¹, Sebastian L Riedel^{1

2}

Affiliations

¹ Technische Universität Berlin, Institute of Biotechnology, Chair of Bioprocess Engineering, Berlin, Germany.
² Berliner Hochschule für Technik, Department VIII - Mechanical Engineering, Event Technology and Process Engineering, Laboratory of Environmental and Bioprocess Engineering, Berlin, Germany.

Abstract

The enhanced material properties exhibited by the microbially synthetized polyhydroxyalkanoate (PHA) copolymer poly(hydroxybutyrate-co-hydroxyhexanoate) [P(HB-co-HHx)] evidence that this naturally biodegrading biopolymer could replace various functionalities of established petrochemical plastics. In fact, the thermal processability, toughness and degradation rate of P(HB-co-HHx) can be tuned by modulating its HHx molar content enabling to manufacture polymers à-la-carte. We have developed a simple batch strategy to precisely control the HHx content of P(HB-co-HHx) to obtain tailor-made PHAs with defined properties. By adjusting the ratio of fructose to canola oil as substrates for the cultivation of recombinant Ralstonia eutropha Re2058/pCB113, the molar fraction of HHx in P(HB-co-HHx) could be adjusted within a range of 2-17 mol% without compromising polymer yields. The chosen strategy proved to be robust from the mL-scale in deep-well-plates to 1-L batch bioreactor cultivations.

Keywords: PHA; Ralstonia eutropha; biodegradable; bioplastic; poly(hydroxybutyrate-co-hydroxyhexanoate); polyhydroxyalkanoate; scale-up; substrate-flexible.

Grants and funding

This research was supported by the German Federal Ministry of Education and Research, grant number 031B0833A.