Euglena gracilis, a microalga, is capable of synthesizing several valuable components in its cells. An integrated biorefinery that recovers multiple useful components from a single biomass for multiple purposes will further maximize the commercial potential of E. gracilis. This study proposed a sequential extraction method that enables the simultaneous recovery of lipids, proteins, and paramylon from E. gracilis, providing a more sustainable and economically viable alternative to traditional single-product recovery systems. In this study, E. gracilis was cultivated using 5 g/L diluted corn steep liquor (CSL) as a cost-effective organic substrate to evaluate its nutrient removal efficiency and potential for multiproduct recovery. E. gracilis cultivation for 7 days removed 50% total organic carbon, 51% total nitrogen, and 47% total phosphorus from 5 g/L CSL culture medium. The E. gracilis biomass production rate was 0.154 g/L/d. This study proposed a sequential extraction method consisting of lipid extraction with n-hexane/ethanol, protein extraction with NaOH, and paramylon extraction with SDS-EDTA solution. The extraction of the harvested biomass yielded 0.118, 0.190, and 0.610 g/g lipids, proteins, and paramylon, respectively. Extraction efficiencies were 94.5% for lipids, 89.1% for proteins, and 93.7% for paramylon. Fatty acid profiling of recovered lipids revealed high levels of saturated (C14:0), monounsaturated (C18:1), and essential polyunsaturated fatty acids (C20:5 and C22:6), highlighting their suitability for both biofuel production and nutraceutical applications. The amino acid analysis of recovered proteins revealed a complete and balanced essential amino acid profile, supporting the nutritional value of the protein fraction. This study demonstrated a sequential extraction of lipids, proteins, and paramylon from E. gracilis, resulting in an advanced biorefinery capable of producing multiple products.

 A wastewater treatment system was developed by combining a trickling filter （TF） and vegetable garden-type constructed wetlands （CWs）. The TF （ø140 × H 315 mm × 3 layers） of systems A and B were filled with coarse glass foam. The CWs （W 470 × L 660 × D 330 mm × 2） in systems A and B were filled respectively with fine glass foam and loamy soil as the substrate. The systems parallelly treated synthetic wastewater containing detergents （TOC 196 mg/L, T－N 91 mg/L, T－P 33 mg/L, MBAS 1.6 mg/L） at 5.0－12.5 L/day for over 200 days. The TF removed 82－85% of TOC, while T－N and T－P removals were 24－25% and 10－12%, respectively. The subsequent CWs removed 10－12% of TOC and 40－42% of T－N in the systems. The CWs of system A removed only 40% of T－P, but were able to grow yellow iris, water spinach, sunflowers, cherry tomato, and garden cyclamen. The CWs in system B removed 86% of T－P, leading to poor plant growth. Denitrification was enhanced when straw, as an external carbon source, was immersed in the CWs. SPCs oxidized from LAS by the TF were removed in the CWs. This system is suitable for wastewater treatment with plant growth in warm countries because its treatment performance decreases at low temperatures.