Assessment of the production of bioplastics from industrial wastewater from fish canning industry

At present, the necessity to find a solution to environmental impacts derived from the whole life cycle of plastics, from extraction of fossil resources to disposal, has led to a great attention towards bioplastics. Among them, promising candidate has been seen in Polyhydroxyalkanoates (PHAs), which are both biobased and biodegradable, and have a great potential in consumer goods applications. However, their high production cost make their scaled-up manufacturing and market share still marginal. This work provides an overview on the current state of the art of PHA production in order to identify well-established aspects, as well as future challenges that should be overcome to foster the replacement of plastic by biopolymers. By this point, this thesis investigates, from an environmental perspective, an innovative potential pathway to produce PHA, i.e. using the wastewater derived from mussel processing industry as substrate. Both the pure and mixed culture production are assessed in order to individuate the most sustainable system. The analysis is focalized on the fermentation step, even if the whole production process, inclusive the extraction phase, is assessed. To achieve this goal, a systematic review of Life Cycle Assessment (LCA) studies on PHAs production is firstly performed in order to determine key-LCA decisions. The methodology used to carry out the analysis is the standard LCA methodology (ISO, 2006). The results show that mixed culture PHA fermentation process results in better environmental performance than pure culture one, since the use of glucoamylase enzyme involved in the latter process is highly resource intensive. Considering the evaluation of the whole production process, it emerges that PHAs can be attractive materials for a sustainable bioeconomy if the process and product design incorporates sustainability criteria such as highlighted in this work.