Catalytic and physical features of a naturally immobilized Yarrowia lipolytica lipase in cell debris (LipImDebri) displaying high thermostability.

Lipase activity (337 U/g dry weight of cell debris) was detected in cell debris after ultrasound treatment of Yarrowia lipolytica cells cultivated in residual frying palm oil. It is a naturally immobilized lipase with protein content of 47%, herein called LipImDebri. This immobilized biocatalyst presents low hydrophobicity (8%), that can be increased adjusting pH and buffer type. Despite apparent intact cells, electron microscopy showed a shapeless and flat surface for LipImDebri and optical microscopy revealed no cell viability. Besides, an inferior mean diameter (3.4 mm) in relation to whole cells reveals structure modification. A high negative zeta potential value (- 33.86 mV) for pH 6 and 25 °C suggests that LipImDebri is a stable suspension in aqueous solution. Fourier Transform Infrared Spectra (FTIR) expose differences between LipImDebri and extracellular lipase extract signaling a physical interaction between enzyme and cell debris, which is possibly the reason for the high thermostability (k d = 0.246 h-1; t 1/2 = 2.82 h at 50 °C, pH 7.0). A good adjustment of LipImDebri kinetic data with Hill equation (R 2 = 0.95) exposes an allosteric behavior related to the presence of more than one lipase isoform. These features reveal that LipImDebri can be a good catalyst for industrial applications.

Efficient production of bioactive structured lipids by fast acidolysis catalyzed by Yarrowia lipolytica lipase, free and immobilized in chitosan-alginate beads, in solvent-free medium.

Structured lipids (SL) represent a new generation of lipids, considered bioactive compounds. Medium-chain, oleic (18:1n-9), and medium-chain fatty acid (MCFA) structured lipids (MOM-SL) were produced by acidolysis reaction in solvent-free medium with capric (10:0) and lauric (12:0) free fatty acids (FFAs) and triolein or olive oil, using Yarrowia lipolytica lipase as biocatalyst. MCFAs were rapidly incorporated into sn-1,3 SL in acidolysis reactions with triolein and olive oil, up until 30% of incorporation efficiency of capric and lauric acids in SLs. The kinetics of MCFA incorporation in MOM-SL was influenced by the FFA:TAG molar ratio, and for reactions between triolein and lauric acid, increasing FFA:TAG from 2:1 to 4:1 enhanced MCFA incorporation in SL. Y. lipolytica lipase showed a strictly 1,3-regioselective profile in acidolysis reaction, confirmed by nuclear magnetic resonance spectroscopy. Immobilization of this lipase by microencapsulation in chitosan-alginate beads resulted in similar incorporation efficiency for lauric acid with olive oil TAG and this reaction could be performed for 5 cycles without catalytic activity loss. This lipase showed promising properties as a potential biocatalyst that may be effectively used in production of bioactive structured lipids, which might be applied for prevention of metabolic and inflammatory disorders related to obesity.

Jussara berry (Euterpe edulis M.) oil-in-water emulsions are highly stable: the role of natural antioxidants in the fruit oil.

BACKGROUND: Antioxidants help prevent lipid oxidation, and therefore are critical to maintain sensory quality and chemical characteristics of edible oils. Jussara berry (Euterpe edulis M.) oil is a source of minor compounds with potential antioxidant activity. The aim of this work was to investigate the role of such compounds on the effectiveness to prevent or delay oxidation of oil present in oil-in-water emulsions, and how the emulsions' physical stability would be affected. RESULTS: Jussara berry oil extracted by ethanol extraction, its stripped variations (partially stripped, highly stripped and highly stripped with added butylhydroxytoluene), and expeller-pressed oil were used to prepare oil-in-water emulsions. Jussara berry oils were analyzed before emulsions preparation to ensure their initial quality and composition, and oil-in-water emulsions were analyzed regarding their oxidative and physical stability. Ethanol extracted oil emulsion presented higher oxidative stability than highly stripped oil emulsion with added synthetic antioxidant butylahydroxytoluene (oxidative stability index 45% lower, after 60 days, and reached undetectable levels after 90 days). All emulsions remained physically stable for up to 120 days of storage. CONCLUSION: Our results indicate that natural antioxidants in jussara berry oil protect emulsions from oxidation while keeping physical stability unchanged. © 2018 Society of Chemical Industry.

Use of Yarrowia lipolytica Lipase Immobilized in Cell Debris for the Production of Lipolyzed Milk Fat (LMF).

Lipase immobilized on Yarrowia lipolytica cell debris after sonication of yeast cells (LipImDebri) was used in hydrolysis reaction as a novel strategy to produce lipolyzed milk fat (LMF). Extracellular (4732.1 U/L), intracellular (130.0 U/g), and cell debris (181.0 U/g) lipases were obtained in a 4 L bioreactor using residual frying oil as inducer in 24 h fermentation process. LipImDebri showed a good operational stability retaining 70% of lipolytic activity after the second cycle and 40% after the fourth. The highest degree of hydrolysis (28%) was obtained with 500 mg LipImDebri for 6 h of lipolysis of anhydrous milk fat. LMF produced with LipImDebri presented high contents of oleic (35.2%), palmitic (25.0%), and stearic (15.4%) acids and considerable amounts of odor-active short and medium chain fatty acids (C:4⁻C:10) (8.13%).

Patent Landscape on Structured Lipids Produced by Enzyme Technology.

BACKGROUND: Lipid modification results in several benefits for the food industry, biotechnology advances and human health. Customizing bioactive lipids is very appealing because it improves the product's nutritional quality. Lipases are sustainable biocatalysts that can be reused, show selectivity towards substrates and reactions occur in mild conditions. OBJECTIVES: We aimed at systematically searching for patents deposited worldwide, that approached the production of structured lipids by using lipases as biocatalysts. METHOD: A patent-search strategy was set up in Questel-Orbit and the search strategy adopted was based on the combination of specific keywords in the title/abstract of the documents, encompassing thoroughly the search scope. We revised all patents relating structured lipids produced by enzyme reactions and provided an overview of the main objectives of the patents describing it, as well as a view of the principal depositors, years of publication and principal countries of deposit, as a mean to access the technological landscape on the subject. RESULTS: Forty-four documents, published over the last 34 years, were retrieved. Nine main patents' objectives were found, and the two major groups are: SL with bioactive properties and/or with fatty acids (FA) esterified at specific triacylglycerol positions and SL analogous of natural lipids. China, Japan and USA were the three main patent depositors. CONCLUSION: Although the number of patents retrieved was relatively low, this review indicates that SL production aiming at improvements in nutritional/health and/or physical attributes for food enhancement is a new field, and technological interest and innovation have been increasing over the last ten years.