Harnessing Agri-Food Waste as a Source of Biopolymers for Agriculture

Nowadays, the world is facing a general problem of resource overconsumption and waste overproduction: to address these two issues, the United Nations delivered the 12th Sustainable Development Goal (SDG), which has the objective of ensuring sustainable consumption and production patterns. Currently, polymers are present in every aspect of our lives and have the disadvantage of mostly coming from fossil sources and causing pollution when disposed of the wrong way. Agriculture plays a key role in the overall world environmental issues, being responsible for the creation of between 13 and 21% of global greenhouse gas (GHG) emissions. Moreover, it represents a continuously growing field, producing large amounts of waste. These residues can cause serious environmental concerns and high costs when disposed. However, agri-food waste (AFW) is a natural source of natural biopolymers, such as lignin, cellulose, pectin, and starch, but can also be used as a substrate to produce other non-toxic and biodegradable biopolymers, such as chitosan, polyhydroxyalkanoates (PHAs), and polylactic acid (PLA) through microbial fermentation. These polymers find applications in agricultural practices such as mulching films, soil stabilizers, hydrogels, nanocarriers, and coating for seeds, fruits, and vegetables. The employment of AFW in the production of non-toxic, sustainable, and biodegradable biopolymers for their agricultural utilization is an example of a virtuous circular economy approach that could help agriculture to be more sustainable.