Life Cycle Assessment of a novel process of polyhydroxyalkanoates production with waste and by-products from wine industry value chain

EU wine production accounts for some 60 percent of worldwide output, with France and Italy being the largest wine producer countries in the world (Gaeta and Corsinovi, 2014). The wine industry influences the environment with the use of soil, water, energy, fertilizers and pesticides. In addition it produces liquid and solid organic waste that has to be managed in the proper manner in order to minimize environmental impacts. In recent years, some innovative technologies have been proposed for the valorization of winery waste and by-products (i.e. grape marcs, grape seeds, vinification lees, etc.) (Devesa-Rey et al., 2011). VALSOVIT is a research project funded by Emilia Romagna Region (Italy) which aims to valorize wine industry by-products. Its focus is the development of an integrated strategy for the transformation of waste from the whole oenological supply chain into high added-value products such as polymers, base chemicals, and molecules for the nutraceutical, cosmetic and agrochemical industries. In this framework, a novel experimental process for the valorization of wine lees and sewage sludge is carried out. These winery residues are subject to anaerobic acidogenic fermentation in order to produce volatile fatty acids (VFAs), which in turn are used to feed a mixed microbial community (MMC) able to accumulate polyhydroxyalkanoates (PHAs) granules as carbon and energy intracellular reserve. The last step consists of PHAs extraction using dimethyl carbonate (DMC). Life cycle assessment is applied to calculate and compare the environmental impacts related to the production of one kg of PHAs to those of an analogous amount of a fossil-based plastic (polypropylene, PP), and two bio-based plastics (bio-polypropylene, bio-PP, and polylactic acid, PLA). PHAs produced from wine industry residues show mixed results. Four different scenarios which vary in terms of feedstock used and pre-treatment process are analyzed. Results show that system setup including pyrolysis pre-treatment allows to reduce both energy demand and GHG emissions more efficiently than the setup without pyrolysis. The latter, on the other hand, is technologically simpler and therefore less effort and cost consuming than the one including pyrolysis. No significant differences between the two feedstock used are found in the results. Gaeta and Corsinovi, 2014. Economics, Governance, and Politics in the Wine Market. Palgrave Macmillan, US. Devesa-Rey et al., 2011. Waste Management. 31:2327-2335