Holistic valorization of rapeseed meal utilizing green solvents extraction and biopolymer production with Pseudomonas putida

A rapeseed meal (RSM) valorization scheme was developed to utilize valuable fractions including phenolics (mainly sinapic acid), proteins and polysaccharides. This involved solvent extraction of phenolics, alkali extraction of proteins and fermentation of residual polysaccharide using Pseudomonas putida. For the first time, sustainable Deep eutectic solvents (DESs) were used in the extraction of rapeseed meal phenolics. With yields up to 85.69 % wt. DESs were able to outperform methanol (59.54 % wt.) at sinapic acid extraction. As shown by Conductor like Screening Model for Real Solvents (COSMO-RS), this is because DESs have greater capacity for H-bonding.

Post-extraction RSM hydrolysate was shown to be a viable media for cultivation of P. putida with maximum cell dry weight of 4.89 g l−1 for DES-extracted RSM. 8-carbon and 10-carbon chain length polyhydroxyalkanoate biopolymers were synthesized. Biopolymer accumulation was reduced in RSM derived media due to high nitrogen concentration. These findings are beneficial for the development of a sustainable biorefining scheme based on rapeseed meal.