Process modelling and environmental assessment on the valorization of lignocellulosic waste to antimicrobials

Abstract

The Sustainable Development Goals defined by the United Nations established a roadmap on the way to a sustainable society based on a circular economy in which the residual fractions of process streams emerge as raw materials for the provision of material goods and services. In this context, the approach of biorefineries as the technological scheme for processing integrally renewable resources stands out. Among the different target products, "bioactive" compounds have aroused great interest given their high added value. This work evaluates the environmental profile associated with the valorization of residual lignocellulosic waste streams: olive pruning and eucalyptus residues for the biotechnological production of nisin, an antimicrobial compound produced by Lactoccocus lactis with application in the food preservation and biomedical sectors. Process modelling in combination with Life Cycle Analysis allowed addressing the conceptual design and the environmental assessment of a full-scale production process. As a main conclusion, the technological feasibility of the valorization of waste fractions as sources of fermentable sugars in the biotechnological process has been demonstrated. Moreover, the integral use of the raw materials can allow not only the production of nisin as an economic driver, but also of other biotechnological products such as lactic acid and energy for the self-supply of the process. The main novelty of this manuscript is based on rethinking the valorization of lignocellulosic waste beyond energy recovery to obtain bioproducts with high added value in the market with applicability in the food sector. Although energy recovery is the most widely implemented end-of-life option, the use of lignocellulosic waste as fermentable sugars has been shown to improve sustainability and circularity outcomes.