Sustainable recycling of agri-food waste for industrially important enzyme production: An exclusive overview

Increasing population around the world is leading to higher food demand and enhanced food and crop production. However, a considerable amount of waste is also being generated worldwide, which is difficult to manage. China is the largest agri-food waste producer in the world, with 91.65 million metric tonnes per year, followed by India with 68.76 million metric tonnes. Landfilling and burning of these waste products are aiding environmental pollution with the release of GHGs. Hence, a sustainable management method is required to tackle the agri-food waste. The organic content present in such waste provides an opportunity for utilization for industrially important enzyme production. The production of enzymes requires a specific substrate to help in the growth of the microorganism, along with high enzyme production. Furthermore, the nutrient requirement for enzyme production may differ from bacterial growth. Hence, the complex consortia of agri-food waste may provide a suitable substrate for the production of various enzymes. However, the utilization of such waste for enzyme production can be challenging in terms of the complexity and unpredictability of the composition. Other factors, such as microplastics and heavy metal contamination, may produce positive or negative results during fermentation. This review discusses global agri-food waste production and the harmful effects of traditional disposal methods. Furthermore, the main discussion follows the composition of agri-food waste and its utilization for the production of various industrially important enzymes. Additionally, the review links the idea of agri-food waste utilization for enzyme production with green chemistry and UN sustainability goals.