In this special issue of the PCT Journal, we present 15 academic papers addressing themes of sustainability and circular economy in industrial and agricultural sectors, biodiversity importance and biological control in aquaculture and farming, the potential of agricultural and organic waste for biofuel generation and as inputs in food production systems, and implementing ecological technologies like aquaponics for sustainable food production. Additionally, methods for improving production efficiency and environmental impact of crops like chili and tomato through elicitors and studying soil microbial communities are explored.