Valorization of Wine Lees to Polyhydroxyalkanoates

In the last years, research focused on the conversion of waste biomasses, and several other residues into value-added products such as new materials and chemicals [1]. In particular, the valorization of winery waste has received significant attention. The International Organization of Vine and Wine’s report shows that, in 2020, about 5 million of tonnes of wine was produced only in Italy. Wine lees, one of the main by-products of the wine industry, are a polluting substrate, and massive volumes (up to 0.3 million t) are indeed yearly produced in Italy. [2]. This work aims to exploit wine lees to obtain high-added value products. Although these residues have been already proposed for the recovery of compounds such as tartaric acid, ethanol, and antioxidants to reduce disposal costs [3], this is the first time that wine lees were explored as a substrate for the proficient microbial production of polyhydroxyalkanoates (PHAs), a completely biodegradable and biocompatible bioplastic. With this purpose, the PHAs accumulation by Cupriavidus necator DSM 545, Hydrogenoflava pseudoflava DSM 1034, and Pseudomonas oleovorans DSM 1045, was studied in different growth conditions on Prosecco wine lees and PHAs were determined in bacterial biomass. C. necator DSM 545 displayed the highest performances with a CDW (cell dry weight) and PHAs content of 4.90 ± 0.41 g/L and 60.30 ± 3.97%, respectively. Although fine-tuning fermentation parameters is needed to improve PHAs yields, these preliminary results pave the way for the future industrial exploitation of wine lees into bioplastics. References [1] A. P Gupte, M. Basaglia, S. Casella, & L. Favaro. Renewable and Sustainable Energy Reviews 167 (2022) 112673. [2] M. Lucarini, A. Durazzo, G. Lombardi-Boccia, A. Romani, G. Sagratini, N. Bevilacqua, F. Ieri, P. Vignolini, M. Campo, & F. Cecchini, in Biorefinery Production Technologies for Chemicals and Energy A. Kuila and M. Mukhopadhyay (Eds.), 2020 p. 91 [3] A. De Iseppi, M. Marangon, S. Vincenzi, G. Lomolino, A. Curioni, & B. Divol. Lwt 136 (2021) 110274. Acknowledgment This work was partially supported by the University of Padova with the following research projects BIRD234877/23, DOR2352129, DOR2251254/22; DOR2107797/21, DOR2084579/20, DOR1928058/19, BIRD210708