Role of animals in waste management with a focus on invertebrates’ biorefinery : An overview

Animals may at times be actively involved in waste management activities. Although occasionally still encountered today, in the past animals were used to transport wastes. Moreover, they can be of significant use in processing putrescible waste. Indeed, worms and fly larvae, while promoting biodegradation and stabilisation, may additionally represent a source of biofuels, specifically biodiesel derived from their fat, and/or of proteins from their biomass (de-fatted and non). In the regenerative system of the circular economy, where waste and resources are interchangeable, the use of animals to process waste and the consequent use of those animals to recover materials and renewable energy represent a perfect fit. This interrelationship has displayed good potential in reducing environmental impacts compared to conventional disposal methods and feed/food preparation. However, the insect-biorefinery (or better the invertebrate-biorefinery) concept should be better elucidated, particularly with regard to the implementation of best safety practices when making a chain to include waste, insects, and feed/food, and, in defining a complete and clear set of regulations. This review provides an overview of the potentially beneficial use of worms and insects in waste management, taking into consideration that enforced legislation is not currently equipped to approve the necessary guidelines aimed at ensuring a safe and well-structured application of a new invertebrate biorefinery economy, and likewise, the population has not yet been sufficiently well informed to be able to form a favourable opinion.