Liberation Of Free Fatty Acid Research Articles

Influence of Lactobacillus plantarum on managing lipolysis and flavor generation of Staphylococcus xylosus and Saccharomyces cerevisiae in fish paste

To investigate the influence of Lactobacillus plantarum on managing lipolysis and flavor generation of Staphylococcus xylosus and Saccharomyces cerevisiae, three strains, Lactobacillus plantarum 120 (Lp-120), Staphylococcus xylosus 135 (Sx-135) and Saccharomyces cerevisiae 31 (Sc-31), isolated from traditional fermented fish were cocultured in fish paste with and without the addition of tert-butylhydroquinone (TBHQ). For comparison, the groups without inoculation of Lp-120 were acidified by glucono-delta-lactone (GDL) to exclude the effect of acidogenesis by Lp-120. The results showed that Sx-31 exhibited the highest liberation of FFAs at 4911 mg/kg dry matter (DM), followed by Sx-135 (4661 mg/kg DM) under monoculture and acidic conditions. However, when co-inoculated with Lp-120, although the growth of Sc-31 was slightly promoted, its lipolytic activity declined dramatically as evidenced by the lowest FFA concentration of 3414 mg/kg DM, accompanied by decreased free fatty acid (FFA) oxidation. Furthermore, when cocultured with Lp-120, the growth of Sx-135 was remarkably inhibited, and the release of FFAs (3984 mg/kg DM) also showed a moderate decline, but FFA oxidation was at the highest level. The results suggested that during fermentation of fish with the mixed-culture of the three strains, the liberation and oxidation of FFAs mainly resulted from Staphylococcus xylosus, followed by Saccharomyces cerevisiae. However, Lactobacillus plantarum inhibited the lipolysis and flavor generation caused by Staphylococcus xylosus and Saccharomyces cerevisiae, especially Saccharomyces cerevisiae.

Lipolytic bacteria and the dynamics of flavor production in Indonesian tempeh

Abstract. Nur N, Meryandini A, Suhartono MT, Suwanto A. 2020 Lipolytic bacteria and the dynamics of flavor production in Indonesian Tempeh. Biodiversitas 21: 3818-3825. During the process of tempeh maturation, lipolytic bacteria become an integral part of tempeh and even have important roles in determining the quality of resulting tempeh. This study was conducted to examine correlation between lipolytic bacteria which were present in three tempeh samples i.e. CMG, EMP, RTI, and their roles in liberation of free fatty acid. Lipolytic bacteria were found in each tempeh sample which were approximately 0.1 % of total bacterial population. CMG harbored the highest lipolytic bacterial population at 1.04 × 106 cfu g-1 followed by EMP at 2.88 × 105 cfu g-1, and RTI at 1.72 × 104 cfu g-1. Tempeh aroma and texture showed strong correlation between the numbers of bacterial population during the period or stages of tempeh maturation. Moreover, we also found a unique correlation between dynamic of lipolytic population and aroma changes. Free fatty acid profiling indicates that lipolysis activity was presence during fermentation of tempe where each tempeh samples showed some differences in liberation of dominant free fatty acid. 16S rRNA sequencing from a hundred of lipolytic isolates was identified and classified as member of the phylum Proteobacteria, Firmicutes, and Actinobacteria, other isolates were classified as uncultured clone.

The role of microbes in free fatty acids release and oxidation in fermented fish paste

To better understand the role of fermentative microorganisms in lipid changes during the processing of fermented fish, sterile fish paste with or without the antioxidant tert-butylhydroquinone (TBHQ) was used to investigate the roles of three strains isolated from traditional fermented fish in free fatty acid (FFA) liberation and lipid oxidation. The results showed that the addition of 0.03% TBHQ had no significant influence (P > 0.05) on the strain growth but could effectively inhibit fatty acid oxidation. Staphylococcus xylosus 135 demonstrated the highest liberation of FFAs, followed by Saccharomyces cerevisiae 31, with its released FFAs being almost all polyunsaturated fatty acids (PUFA). Furthermore, the highest amount of PUFA oxidation in FFAs was observed in the samples inoculated with Staphylococcus xylosus 135 (802 mg/kg DM), followed by Lactobacillus plantarum 120 (476 mg/kg DM) and Saccharomyces cerevisiae 31(388 mg/kg DM). The results suggested that Staphylococcus xylosus may play a major role in the lipolysis and lipid oxidation during the processing of fermented fish. Lactobacillus plantarum also contributed to the fatty acid oxidation although it had no obvious lipolysis ability.

Acinetobacter soli SP2 Capable of High-Efficiency Degradation of Food Emulsifier Polysorbate 80.

Emulsifiers like polysorbate family, carboxymethyl cellulose are widely used in the preparation of drugs, vaccines, food, cosmetics, and skin care products. In this study, strain SP2 is isolated for the high-efficiency utilization of emulsifier as its sole carbon and energy source. Strain grows on the polysorbate family with generation time ranging from 0.8 to 2.2h. It is sensitive to ampicillin, gentamicin, imipenem, penicillin, and vancomycin, but resistant to amikacin, cefoxitin, erythromycin, kanamycin, nalidixic acid, and tetracycline. Based on 16S rRNA gene, strain is identified as Acinetobacter soli. Compared to M. pamicella, which is capable of degrading 50% polysorbate 80 within 3 days, isolate PS2 could dispose 51.6% polysorbate 80 within only 8h. Using cell crude extract from strain SP2, the liberation of free fatty acid in the reaction mixture containing polysorbate 80 suggests that the mechanism for polysorbate utilization belongs to the β-oxidation.

Distinct Pathways of ERK1/2 Activation by Hydroxy-Carboxylic Acid Receptor-1

Mechanistic investigations have shown that, upon agonist activation, hydroxy-carboxylic acid receptor-1(HCA1) couples to a Gi protein and inhibits adenylate cyclase activity, leading to inhibition of liberation of free fatty acid. However, the underlying molecular mechanisms for HCA1 signaling remain largely unknown. Using CHO-K1 cells stably expressing HCA1, and L6 cells, which endogenously express rat HCA1 receptors, we found that activation of ERK1/2 by HCA1 was rapid, peaking at 5 min, and was significantly blocked by pertussis toxin. Furthermore, time course experiments with different kinase inhibitors demonstrated that HCA1 induced ERK1/2 activation via the extracellular Ca2+, PKC and IGF-I receptor transactivation-dependent pathways. In addition, we observed that pretreated the cells with M119K, an inhibitor of Gβγ subunit-dependent signaling, effectively attenuated the ERK1/2 activation triggered by HCA1, suggesting a critical role for βγ-subunits in HCA1-activated ERK1/2 phosphorylation. Furthermore, the present results also indicated that the arrestin2/3 were not required for ERK1/2 activation. In conclusion, our findings demonstrate that upon binding to agonist, HCA1 receptors initially activate Gi, leading to dissociation of the Gβγ subunit from activated Gi, and subsequently induce ERK1/2 activation via two distinct pathways: one PKC-dependent pathway and the other IGF-IR transactivation-dependent pathway. Our results provide the first in-depth evidence that defines the molecular mechanism of HCA1-mediated ERK1/2 activation.

Metabolic phenotyping of the cyanobacterium Synechocystis 6803 engineered for production of alkanes and free fatty acids

We demonstrate a simple high-throughput single-cell approach that exploits the ultrahigh brightness and non-invasive nature of synchrotron infrared beam to characterize strains of the cyanobacterium Synechocystis 6803 (S. 6803) constructed with altered metabolic traits affecting the acyl-CoA pool. Their metabolic responses to the modified traits were phenotyped by single-cell synchrotron radiation Fourier transform infrared (SR-FTIR) spectromicroscopy and multivariate analysis. SR-FTIR difference spectra and cluster vector plots segregated the strains as phenotypic populations based on signals in the hydrocarbon and biomolecular fingerprint regions, although each population incorporated a stochastic distribution of cells with different metabolic properties. All engineered strains exhibited an increase in FTIR features attributed to functional groups in hydrocarbon, fatty acid (FA), and/or FA ester chains, and a decrease in polysaccharide features. The metabolic signatures obtained by SR-FTIR were consistent with detailed qualitative and quantitative metabolic information provided in GC/MS/NMR data. A strain with extra copies of the FAR and FAD genes, encoding, respectively, the fatty acyl-ACP reductase and fatty aldehyde decarbonylase enzymes in the alkane biosynthesis pathway, showed up to a fivefold increase in the intracellular levels of heptadecane, a threefold increase in 9-heptadecene, and a significant increase in secreted 16:0 and 18:0 free FAs (FFAs). Inactivation of the AAS gene, encoding acyl-ACP synthetase, prevented re-thioesterification of FFAs generated from membrane lipid recycling and led to elevated levels and of intracellular FFAs of an altered composition, and a decrease in heptadecane and secreted FFAs. Introduction of a FatB gene, encoding a thioesterase (TE), which catalyzes the liberation of FFAs from acyl-ACP, yielded little effect in itself. However, the activity of the TE enzyme was clearly manifested in combination with AAS inactivation; A TE-containing train lacking AAS showed a dramatic (30-fold) increase in intracellular FFAs (with the majority being 16:0) and increases in heptadecane and secreted FFAs.

Distinct Kinetic and Spatial Patterns of Protein Kinase C (PKC)- and Epidermal Growth Factor Receptor (EGFR)-dependent Activation of Extracellular Signal-regulated Kinases 1 and 2 by Human Nicotinic Acid Receptor GPR109A

Nicotinic acid (niacin) has been widely used as a lipid-lowering drug for several decades, and recently, orphan G protein-coupled receptor GPR109A has been identified as a receptor for niacin. Mechanistic investigations have shown that, upon niacin activation, GPR109A couples to a G(i) protein and inhibits adenylate cyclase activity, leading to inhibition of liberation of free fatty acid. However, the underlying molecular mechanisms for GPR109A signaling remain largely unknown. Using CHO-K1 cells stably expressing GPR109A and A431 cells, which are a human epidermoid cell line with high levels of endogenous expression of functional GPR109A receptors, we found that activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) by niacin was rapid, peaking at 5 min, and was significantly blocked by pertussis toxin. Furthermore, time course experiments with different kinase inhibitors demonstrated that GPR109A induced ERK1/2 activation via the matrix metalloproteinase/epidermal growth factor receptor transactivation pathway at both early and later time points (2-5 min); this pathway was distinct from the PKC pathway-mediated ERK1/2 phosphorylation that occurs at early time points (≤2 min) in response to niacin. Overexpression of Gβγ subunit scavengers βARK1-CT and the Gα subunit of transducin led to a significant reduction of ERK1/2 phosphorylation, suggesting a critical role for βγ subunits in GPR109A-activated ERK1/2 phosphorylation. Using arrestin-2/3-specific siRNA and an internalization-deficient GPR109A mutant, we found that arrestin-2 and arrestin-3 were not involved in GPR109A-mediated ERK1/2 activation. In conclusion, our findings demonstrate that upon binding to niacin GPR109A receptors initially activate G(i), leading to dissociation of the Gβγ subunit from activated G(i), and subsequently induce ERK1/2 activation via two distinct pathways, one PKC-dependent pathway occurring at a peak time of ≤2 min and the other matrix metalloproteinase-dependent growth factor receptor transactivation occurring at both early and later time points (2-5 min).

Formation and degradation of lipid bodies found in the riboflavin-producing fungus Ashbya gossypii

Microdroplets in the hyphae of Ashbya gossypii were found to become stained by Nile red. Purification of the stainable substance showed that the yellow fluorescent bodies consisted of triacylglycerol. During growth on glucose as the carbon source 8%–12% of the mycelial dry weight was found to be neutral lipid. When glucose declined in the medium, the content decreased to 3%–4% and the respiration quotient shifted to 0.6 indicating a reserve function of the fat. The fatty acid composition of the storage lipid was found to be strongly influenced by the carbon source. Mycelia cultivated on glucose contained 5% linoleic acid and 20% palmitoleic acid in their neutral fat while linoleic acid made up 54% and palmitoleic acid was not detectable (< 0.1%) in soybean-oil-grown mycelia. When plant oil was given as the sole carbon source, the fatty acid composition of the storage lipid showed a high similarity to the fed fat. 14C-labelled free oleic acid added to a culture growing on soybean oil was immediately incorporated into the fungal lipid. A pulse of 0.9 g/l free palmitoleic acid, fed during growth on olive oil, increased the content of this particular fatty acid in the fungal triacylglycerol from 0.8% to 9.6%. In addition, a liberation of free fatty acid and diacylglyceride was found in the culture supernatant when pure triolein was given as the sole carbon source. Obviously, the fungus cleaved the lipid serving as the carbon source extracellularly and used the liberated fatty acids for its storage lipid formation.

The role of phospholipases from inflammatory macrophages in demyelination.

Activated macrophages harvested from rat peritoneum were shown to contain phospholipase A1, A2 and lysophospholipase activities which were defined on a series of radiolabelled phospholipid substrates. During in vitro culture of these elicited macrophage populations, phospholipase enzymes were secreted into the culture medium. Radiolabelled myelin, prepared from young rats after intracerebral injection of 14C acetate, was used as a substrate to analyze the susceptibility of central nervous system (CNS) myelin to attack by cell-associated and secreted macrophage enzymes. Homogenates of peritoneal macrophages degraded the myelin lipids at acid pH; phosphatidyl choline (PC) and ethanolamine phosphatide (EP) were both degraded with liberation of free fatty acid and small amounts of lysolipids. The ethanolamine lipids were most vulnerable; up to 20% of this fraction was degraded in six hours. Selected batches of macrophage culture supernatant similarly degraded the myelin EP at acid pH. These results suggest that phospholipase enzymes, released from activated macrophages in close proximity to the myelin sheath, may participate in primary demyelination in inflammatory CNS lesions.

The effect of CMP on the release of free fatty acids of rat brain in vitro.

With CMP, phosphatidylcholine can be converted to diacylglycerols and CDPcholine by reversal of the cholinephosphotransferase that is normally used for synthesis. Incubation of homogenates of rat brains at pH 8 with 20 mM MgCl2 increased the free fatty acid (FFA) levels 30 to 117%. The FFA levels increased 62 to 212% when 4 mM CMP was included. Diacylglycerols were also produced. Hydrolysis of the diacylglycerols to FFA was markedly inhibited by inclusion of 3 mM diisopropylphosphofluoridate in the incubation mixture. The composition of the fatty acids released by CMP resembles that of phosphatidylcholine except for some polyunsaturated fatty acids. These may have been released from the ethanolamine glycerophospholipids. Most of the CMP-stimulated release of FFA was blocked by inclusion of 1 mM CDPcholine in the incubation mixture. Rat brains were labeled by intracerebral injection of [3H]oleic acid. The labeled oleic acid was released primarily from phosphatidylcholine. Thus, measurements of both mass and radioactivity confirm that the reversal of cholinephosphotransferase followed by diacylglycerol lipase can be an important pathway for the liberation of FFA from phosphatidylcholine.

The Effect of X-Irradiation on the Phospholipase and Antioxidant Activities of Rat Intestinal Mucosa

The antioxidant effect of intestinal mucosa is the result of the liberation of free fatty acid from phospholipid by phospholipase. The fatty acid binds the iron and thus inhibits peroxidation of unsaturated lipids in the test system. The phospholipase and antioxidant activity of rat intestinal mucosa decreases markedly 24 hours postirradiation and to approximately the same extent. (auth)

The Preservation of Aqueous Preparations Containing Nonionic Surfactants I. : Growth of Microorganisms in Solutions and Dispersions of Nonionic Surfactants

Studies have shown that various microorganisms, including Pseudomonas aeruginosa, Aspergillus niger, Penicillium notatum , and Monilia albicans are capable of growing in solutions and dispersions of nonionic surfactants of the fatty acid ester type. It was observed that these organisms are capable of splitting the ester linkages of these surfactants. This is first evidenced visually by the appearance of free fatty acids in the inoculated surfactant solutions. Further study revealed that these test organisms produce esterases which split the fatty acid from the surfactant molecule. The presence of esterases was demonstrated using a tributyrin testing procedure. The liberation of free fatty acid from polyoxyethylene 20 sorbitan monostearate (Tween® 60) solutions is reported.