Waste fat biodegradation and biomodification by Yarrowia lipolytica and a bacterial consortium composed of Bacillus spp. and Pseudomonas putida

Abstract

Fats, oils, and greases (FOGs) are a particular environmental threat. Biodegradation of FOGs is a challenge and in this study the biodegradation of waste cooking fats, namely butter and olive oil, was studied using a non‐conventional yeast, Yarrowia lipolytica strain LFMB 20, and a bioaugmentation product consisting of Bacillus spp. and Pseudomonas putida CP1 strain. The microorganisms were grown aerobically in shake‐flask experiments in an enriched medium supplemented with ca 0.85% w/v of waste fat. Analysis of the remaining substrate showed a removal of ca 90% of the fat by the yeast at the end of the incubation, while the bacteria removed ca 95% of both fats. Growth rate, biomass production and biomass yield per unit of fat consumed were all higher for the yeast compared to the bacterial consortium. The bacterial consortium exhibited autolysis and a significant decrease in its DCW value at the late growth phases of both fat substrate cultures. The main fatty acids (FAs) present in both fats were linoleic (Δ9,12C18:2), oleic (Δ9C18:1), palmitic (C16:0), palmitoleic (Δ9C16:1) and stearic (C18:0) acid. Both the bacterial consortium and Y. lipolytica preferentially removed Δ9C18:1 from the medium, while a negative selectivity against C18:0 was reported. Both inocula produced microbial mass that contained intra‐cellular lipid quantities, but the bacterial consortium gave significantly higher lipid in DCW values compared with the yeast (maximum values up to ca 63% w/w for the butter and ca 42% w/w for the olive oil while the respective values for both lipids were 22% ± 2% w/w for Y. lipolytica). In all cases, intra‐cellular lipids in DCW values decreased during the late growth phases, while their FA composition differed with those of the substrate fat.

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

“…Therefore, the ability of Y. lipolytica strains to produce biomass rich in various nutritional components on available cheap carbon sources like oily wastes is highly desired. Furthermore, biodegradation of these wastes is very important for environmental protection (Katre et al 2012;Saygün et al 2014;Vasiliadou et al 2018;Tzirita et al 2018). Additionally, there are no generated wastes according to the take-make-dispose concept (Lopes et al 2019).…”

Microbial valorization of waste cooking oils for valuable compounds production – a review

“…When bacterial consortium reached the stationary phase, lipids previously accumulated were re-consumed. The composition of these microbial lipids were dependent on growth phase, being only composed by unsaturated fatty acids (oleic and linoleic acids) during exponential phase and mainly composed by saturated fatty acids (stearic and palmitic acid) during the late growth phase (Tzirita et al, 2018).…”

“…The addition of magnesium and phosphate to Y. lipolytica cultures gave rise to an improvement of lipid content (Liu et al, 2015). To enhance the solubility of WCO and its bioavailability to microbial cells, several authors add to the medium chemical surfactants or emulsifiers, such as Tween 80 (Arous et al, 2017;El Bialy et al, 2011;Papanikolaou et al, 2011;Tzirita et al, 2018) or arabic gum (Lopes et al, 2019). However, Patel and Matsakas (2018) found an alternative approach to improve the accessibility of Cryptococcus curvatus cells to the WCO, avoiding the use of chemical compounds.…”

Yarrowia lipolytica and Lactobacillus paracasei Solid State Fermentation as a Valuable Biotechnological Tool for the Pork Lard and Okara’s Biotransformation

“…The pork lard was associated for a long time as a potential cause of vascular and heart disease [8] and therefore not used as much in food preparation. The price of animal fat is relatively low, which makes it a cheap and promising substrate for microbial fermentation [9] in order to obtain valuable metabolites (i.e., short-and medium-chain fatty acids) [10].…”

“…However, to the best of our knowledge, the fermentation of both okara and pork lard in a yeast and lactobacilli co-culture has not been investigated previously. Instead, Tzirita et al (2018) [10] reported on waste fat biodegradation by Y. lipolytica, Bacillus spp. and Pseudomonas putida consortium in order to produce lipids with significant industrial, ecological, and biotechnological interest.…”