Waste Frying Oils as Substrate for Enzymatic Lipolysis: Optimization of Reaction Conditions in O/W Emulsion

Abstract

any case our results demonstrate that WFO are a good substrate for enzymatic hydrolysis, comparable to food-grade vegetable oils, providing an alternative route for the valorization of this waste.Abstract Waste frying oils (WFO) can be both environmental pollutants and a source of valuable products. In this work we explore the conversion of WFO into surface-active substances, such as FFA and partial glycerides, through enzymatic hydrolysis in O/W emulsion. Two different WFO and three lipases of different origin were tested. In addition, we optimized the conditions for the production of O/W emulsions to be used as reaction medium as well as several reaction parameters, such as the type of enzyme and its concentration, the pH, and the presence of Ca 2+ ions. Gum arabic-stabilized emulsions with an oil fraction of 0.15 proved to be the most adequate owing to their high interfacial area and short-term stability. The physicochemical characterization of both WFO revealed the presence of an increased amount of surface-active matter relative to food-grade vegetable oils. These substances, mainly FFA, can interfere with lipase action and reduce the reaction rate. However, the extent of hydrolysis was only slightly affected by them, and remained fairly similar to that achieved with a control mixture of food-grade vegetable oils. The product distribution depended on the enzyme used. Pseudomonas fluorescens lipase was found to be particularly suitable for the production of partial glycerides (mono-and diacylglycerols), which are in great demand by the food industry. In Electronic supplementary material The online version of this article (

Effect of emulsification and hydrolysis pretreatments of waste frying oil on surfactin production

“…(Granada, Spain) and filtered to remove solids. Table shows the fatty acid profile of the oil together with other properties of the WFOs determined as previously described . For comparison purposes, we also employed extra virgin olive oil (VO, purchased from a local store).…”

“…WFO emulsions and hydrolysis were performed according to the methods described by Moya Ramírez et al . Briefly, 15% ( v / v ) of WFOs were emulsified in a 0.5 mol L –1 phosphate buffer containing 100 mg mL −1 of gum arabic (GA) as emulsifier with a Ultra‐Turrax® T25 homogenizer (Ika‐Werke, Staufen, Germany) followed by a sonication step (Q500, Q Sonica, Newtown, CT, USA).…”

“…The reaction was carried out at 37 °C and 120 rpm for 8 h. Next the enzyme was heat‐deactivated at 100 °C for a minute. After this treatment, the degree of hydrolysis was 48.20% ± 2.39%, and the mole fractions of triglycerides, diglycerides, monoglycerides and free fatty acids were 0.277, 0.281, 0.090 and 0.352, respectively …”

Hydrolytic Activity of Castor Bean Powder: Effect of Gum Arabic, Lipase and Oil Concentrations

“…The aim of this work was to study castor bean seed lipase as a biocatalyst in hydrolysis reactions, in the form of lipase powder (LP), evaluating the presence of gum arabic as surfactant and its effect on reaction systems containing different substrate and LP concentrations. High oleic sunflower oil was used as substrate and gum arabic was chosen as surfactant since they had already been used with castor bean powders and other enzymes [2][3][4][5][6]. Actually, some authors [6] optimized emulsion stability before beginning lipase reaction experiments assuming that the best emulsion implies the best lipase performance.…”

Conversão enzimática de triacilgliceróis em mono e diacilgliceróis de interesse industrial

“…Além disso, esse comportamento também foi observado porMENDES et al (2006), cujos resultados para a hidrólise de água residual com diferentes níveis de gordura indicaram maior rendimento de formação de composto intermediário, requerendo aplicação de maior calor para atingir rendimento de processo adequado, com declínio progressivo na formação de compostos intermediários e mudança na reação de hidrólise para formação progressiva de ácidos graxos livres, como também pode ser observado na Figura 20. da obtenção de altos teores de MAGs e DAGs(MOYA-RAMIREZ et al, 2016). Houve uma intensidade de reação mais elevada, em particular para 3,5 h de reação, com uma gama máxima de efeitos entre hidrólise, que geraram dioleína e monooleína, foram processadas.…”