توصيفگر ها :
ريزجلبك , پسماند غذايي رستوران , زيستتوده , ليپيد , روغن فراسودمند , سوخت زيستي , سندسموس كوادريكادا , تتراسلميس سوئسيكا
چكيده انگليسي :
Microalgae possess a unique ability to absorb and eliminate nutrients such as nitrogen, phosphate, and organic carbon, making them efficient tools for bioremediation and environmental protection. They also produce biomass rich in valuable compounds like lipids, suitable for biofuel production or nutritional applications. The rapid rise in food waste (FW), particularly from restaurants, has intensified environmental challenges such as greenhouse gas emissions, water pollution, and resource loss. Utilizing FW as a cultivation medium for microalgae offers an effective approach to mitigating these impacts. This study identified FW from restaurants, classifying it into four main categories: vegetable (VWH, 33.2%), bread (BWH, 11.0%), rice (RWH, 15.2%), and meat (MWH, 19.3%), alongside a combined sample (CWH). These were subjected to microwave-assisted acid hydrolysis (optimized conditions: 96 °C, 340 W, 1.45 % HCl, 11.1 min) to produce media suitable for microalgal growth. Parameters such as growth rate, biomass production, biochemical composition, biodiesel properties, lipid profile, and nutrient removal efficiency were analyzed in S. quadricauda (freshwater) and T. suecica (marine) under mixotrophic conditions at hydrolysate concentrations of 2, 4, and 8% v/v. The CWH-8% yielded the highest growth performance in S. quadricauda (growth rate: 1.42 day⁻¹, doubling time: 0.49 days, biomass: 1.86 g/L). For T. suecica, VWH-8% was optimal (growth rate: 0f.75 d⁻¹, doubling time: 0.92 d, biomass: 1.99 g/L). MWH showed the lowest productivity for both species. Pigment analyses revealed the highest chlorophyll a (13.98 mg/L) and b (5.15 mg/L) contents in S. quadricauda grown on CWH-8%, while T. suecica achieved the highest carotenoid content (4.31 mg/L) on VWH-8%. Lipid accumulation in S. quadricauda ranged from 13.27 to 32.28%, with the highest accumulation in BWH-8%. In T. suecica, lipids ranged from 8.21% to 32.69%, with the highest accumulation in VWH-2%. Fatty acid profiles showed palmitic acid (C16:0) and oleic acid (C18:1) as predominant in both species. S. quadricauda exhibited high ω-6 content (9.26–29.06%) but low ω-3 levels, with maximum DHA (0.57%) in VWH. In contrast, T. suecica showed high ω-3 content (6.69-14.19%). Biodiesel properties, including cetane number (51.88–64.17), iodine value (33.91–84.98 g I2/100g), and higher heating value (39.94–40.48 MJ/kg), met international standards. However, the cold filter plugging point of S. quadricauda (>30 °C) was unsuitable for cold climates, while that of T. suecica (1.83–13.19 °C) made it a better candidate for use in colder regions.
