Waste Cooking Oils as Feedstock for Lipase and Lipid‐Rich Biomass Production

Abstract

Approximately 1 million tons of waste cooking oils (WCO) are generated in European Union per year. Oftentimes, these oily wastes are discharged through public sewerage systems, increasing the water treatment costs in wastewater treatment plants. The oleaginous yeast Yarrowia lipolytica W29 is used to simultaneously degrade WCO and to produce lipase (market demand is increasing due to its application in the field of bioenergy). A statistical experimental design based on Taguchi method is employed to assess the effect of initial medium pH, WCO, and arabic gum concentration on lipase production. Initial medium pH is found to be the most significant parameter and the interaction between WCO and arabic gum concentration had the highest influence for lipase production. Additionally, the effect of oxygen mass transfer is studied in batch cultures in a stirred tank bioreactor and the maximum lipase activity (12 000 U · L−1) is obtained at kLa of 16 h−1. Simultaneously with lipase production, also lipid‐rich biomass (48% of lipids mass per dry cellular mass), enriched in unsaturated fatty acids (oleic and linoleic acids) is obtained. Practical Applications: In this work it was demonstrated the possibility of replacing an expensive edible oil (olive oil) by a non‐edible oil waste (WCO) for lipase production. Moreover, no more wastes are produced, since whole cells of Yarrowia lipolytica W29 (lipid‐rich biomass), are a potential source for food supplements. Thus, the bioprocess described fulfill the requisites of circular economy: a low cost substrate is used as raw material, added‐value products (lipase and lipid‐rich biomass) are obtained and no further wastes are generated (take‐make‐dispose concept). Waste cooking oils (WCO) are generated from vegetable oils used at high temperatures in food frying. The biological degradation of WCO by the oleaginous yeast Yarrowia lipolytica W29, with concomitant production of added‐value compounds (lipase and lipid‐rich biomass), allows the reduction of pollutant burden of these oily wastes.

Statistical evaluation of growth parameters in biofuel waste as a culture medium for improved production of single cell protein and amino acids by Yarrowia lipolytica

“…These can be conventional (starch, molasses, fruit, and vegetable wastes) and nonconventional (different fractions of petroleum, natural gas, ethanol, methanol, lignocellulosic biomass, waste cooking or motor oils, animal-waste fats, or waste streams from various industries). Because of such inexpenside feedstocks, microbial mass and microbial lipid produced by Yarrowia lipolytica (single cell protein and single cell oil) are considered as environmentally friendly processes (Dourou et al 2018;Groenewald et al 2013;Jach et al 2017;Jach and Serefko 2018;Katre et al 2012;Lopes et al 2018Lopes et al , 2019Papanikolaou et al 2001Papanikolaou et al , 2003Rywinska et al 2013).…”

Biovalorization of vegetable oil refinery wastewater into value‐added compounds by Yarrowia lipolytica

“…Lipid-rich biomass with 48% lipids in the dry mass was achieved in a medium containing waste cooking oils enriched in UFAs. 34 Y. lipolytica accumulated 15%-25% (w/w) lipids when cultivated on OMW-based media. 20 The efficiency of the optimized medium was elevated in the shake-flask and bioreactor cultures.…”

“…The production of lipid‐rich GRAS biomass in order to use for food or feed supplement is important in the biotechnology of microbial oil when waste fatty materials are employed as substrates . Researchers used different waste fatty materials, such as industrial derivative of tallow, waste cooking oils and OMW, to produce lipid‐rich biomass in previous studies …”

“…Papanikolaou et al obtained 52.0% lipid in the dry biomass by Y. lipolytica from industrial derivative of tallow. Lipid‐rich biomass with 48% lipids in the dry mass was achieved in a medium containing waste cooking oils enriched in UFAs . Y. lipolytica accumulated 15%–25% (w/w) lipids when cultivated on OMW‐based media …”

“…[29][30][31][32] Researchers used different waste fatty materials, such as industrial derivative of tallow, waste cooking oils and OMW, to produce lipid-rich biomass in previous studies. [33][34][35][36] We used VORW as waste fatty material as substrate to produce added-value compounds such as lipase, microbial oil and lipid-rich biomass by Y. lipolytica which allows the reduction of pollutant burden of these oily wastes.…”