Research Centre for Animal Production and Aquaculture, Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria (CREA), Via Beccastecca 345, 41018, San Cesario sul Panaro, MO, Italy.
Department of Civil, Chemical, Environmental, and Materials Engineering (DICAM), University of Bologna, Via Terracini 28, 40131, Bologna, Italy.
Appl Microbiol Biotechnol. 2020 Apr;104(7):2833-2856. doi: 10.1007/s00253-020-10431-3. Epub 2020 Feb 10.
Each year, large quantities of waste cooking oils are produced worldwide which are currently reused mainly for biodiesel production. Since lipids have a very high potential for biomethanation, the production of biogas is a possible alternative for the recycling of edible used oils. The digestion of fats is hindered mainly by their hydrophobicity, which implies a biphasic system with problems of floating and foaming of the oily materials, and by the accumulation of long-chain fatty acids, which are toxic to microbial consortia. The objectives of this review were to highlight the recycling potential of waste cooking oil to biogas production and to facilitate the application of the technology by identifying solutions to overcome biological and engineering limits to its diffusion. Particular attention was paid to the microbial populations involved, to the process factors whose control is important to improve the digestion of fats such as lipid concentration, pH, temperature, and agitation, and to technological solutions whose application also aims to improve digestion, such as pretreatment of raw materials and co-digestion of fats with other feedstocks. The state of the art in reactor designs suitable for lipid digestion was also examined.
每年，全世界都会产生大量的废食用油，目前这些废油主要被重新用于生物柴油生产。由于脂质具有很高的生物甲烷化潜力，因此沼气生产是一种可替代方法，用于回收食用油。脂肪的消化主要受到其疏水性的阻碍，这意味着存在两相系统，存在油性物质浮起和泡沫的问题，以及长链脂肪酸的积累，这对微生物群落有毒。本综述的目的是强调废食用油回收利用生产沼气的潜力，并通过确定克服其扩散的生物学和工程限制的解决方案，促进该技术的应用。特别关注涉及的微生物种群、过程因素，以及对改善脂肪消化很重要的控制因素，例如脂质浓度、pH 值、温度和搅拌，以及应用也旨在改善消化的技术解决方案，例如原材料的预处理和与其他原料的共消化。还检查了适合脂质消化的反应器设计的最新技术。
