Green Chemistry Approaches for Processing of Coniferous Needles and Greenery to Implement Circular Bioeconomy Concepts in Forestry

Replacing fossil-based materials with renewable biomass is crucial for addressing environmental health challenges and advancing the bioeconomy as a key element of sustainable development. Forestry is a significant biomass source, yet a substantial portion of its by-products, including coniferous greenery, remains underutilized. Maximizing the use of these side streams aligns with circular bioeconomy principles and can reduce dependence on fossil-derived materials. Coniferous needles and greenery are rich in biologically active compounds with potential applications in biopharmaceuticals, food and feed supplements, and material sciences. However, conventional extraction methods rely on toxic solvents, such as organochlorine and hydrocarbons, which pose environmental and health risks. This study uses environmentally friendly solvents to explore green chemistry approaches for extracting bioactive compounds from coniferous biomass. Various green solvents were tested, and conventional methods determined extraction yields. The obtained extracts were analysed using gas chromatography–mass spectrometry (GC-MS) to characterize their composition. Among the tested solvents, isopropanol, acetone, propyl acetate, and dimethyl carbonate demonstrated the highest extraction efficiencies while maintaining a favourable environmental and health profile. Dimethyl carbonate emerged as the most promising "green" alternative to hexane, offering improved sustainability, low toxicity, and a 50 % higher extraction yield than hexane for non-polar compounds. The findings support the integration of green solvents into biorefinery processes, enabling the sustainable utilization of forestry biomass while reducing reliance on hazardous chemicals.