Short Fatty Acids Research Articles

Effect of pH, yeast extract and inorganic carbon on chain elongation for hexanoic acid production

Several anaerobic bioconversion technologies produce short chain volatile fatty acids and sometimes ethanol, which can together be elongated to hexanoic acid (C6 acid) by Clostridium kluyveri in a secondary fermentation process. Initiatives are needed to further optimize the process. Therefore, five strategies were tested aiming at elucidating their influence on hexanoic acid production from mixtures of acetic acid, butyric acid and ethanol. pH-regulated bioreactors, maintained at pH 7.5, 6.8 or 6.4 led to maximum C6 acid concentrations of, respectively, 19.4, 18.3 and 13.3 g L−1. At pH 6.8, yeast extract omission resulted in a decrease of the hexanoic acid concentration to 12.0 g L−1 while the addition of an inorganic carbon source, such as bicarbonate, for pH control, increased the C6 acid concentration up to 21.4 g L−1. This research provides guidelines for efficient improved production of hexanoic acid by pure cultures of C. kluyveri, contributing to the state of art.

Changes in fatty acids composition, antioxidant potential and induction period of UHT-treated tea whitener, milk and dairy drink

BackgroundIn developing and developed countries, several versions of safe and shelf-stable Ultra High Temperature, UHT-treated products are manufactured. Terminologies and formulations of UHT-treated tea whitener, milk and dairy drink considerably vary. Comprehensive studies have been performed on UHT-treated milk; however, fatty acids compositional changes and oxidation status of UHT-treated tea whitener and dairy drink at different storage intervals have not been reported in literature.MethodsUHT-treated tea whitener, milk and dairy drink samples (450 each) of the same manufacturing date were purchased from the market and stored at ambient temperature (25-30 °C) for 90 days. At the time of collection, all the samples were only one week old. Samples of UHT-treated tea whitener, milk and dairy drink were regarded as treatments and every treatment was replicated five times. Chemical composition, fatty acid profile, 2, 2-Diphenyl-1-picrylhydrazyle (DPPH) radical scavenging activity, total antioxidant activity, reducing power, antioxidant activity in linoleic acid system and induction period were determined at 0, 45 and 90 days of storage.ResultsFat content in freshly collected samples of UHT treated-tea whitener, milk and dairy drink were 6 and 3.5%. UHT treated milk had highest total antioxidant capacity, antioxidant activity in linoleic acid and 2, 2-Diphenyl-1-picrylhydrazyle (DPPH) free radical scavenging activity followed by UHT tea whitener and dairy drink. In freshly collected samples of UHT-treated milk, concentrations vitamin A and E were 0.46 μg/100 g and 0.63 mg/100 g, respectively. UHT-treated tea whitener had the lowest concentrations of vitamin A and E. With the progression of storage period, amount of vitamin A and E decreased. In freshly collected samples, amount of short, medium and unsaturated fatty acids in UHT-treated milk were 10.54, 59.71 and 27.44%, respectively. After 45 days of storage of UHT-treated milk, the loss of short, medium and unsaturated fatty acid was 7%, 7.1 and 5.8%, respectively. After 90 days of storage of UHT-treated milk, the loss of short, medium and unsaturated fatty acid was 8.53, 13.51 and 11.88%, accordingly. After 45 days of storage of UHT-treated tea whitener, the loss of medium and unsaturated fatty acid was 1.6 and 0.99%, respectively. After 90 days of storage, the loss of medium and unsaturated fatty acids were 8.2 and 6.6%, respectively. The induction period of fresh UHT-treated tea whitener, milk and dairy drink was 15.67, .74 and 7.27 h. Strong correlations were recorded between induction period and peroxide value of UHT-treated products.ConclusionThis investigation disclosed that UHT-treated tea whitener had 6% fat content with no short-chain fatty acids. Antioxidant capacity of UHT-treated milk was higher than dairy drink and tea whitener. Due to the presence of partially hydrogenated fat, oxidative stability of UHT-treated tea whitener was better than UHT-treated milk and dairy drink. Vitamin A and E was not found in UHT-treated tea whitener. For the anticipation of oxidative stability of UHT-treated milk, dairy drink and tea whitener, induction period/ Rancimat method can be used.

Biochemical evaluation of antibacterial activity of short and medium chain fatty acids in broiler

The objective of the present study was to evaluate the antimicrobial effect of short and medium fatty acid chain. Total number of 2000 Cobb broiler chicks (mixed sexes) were commercially purchased from EL Dakahlia poultry company that were 1d old were reared up to 40d of age. Corn and soybean meal based starter and grower diet were supplemented. Chicken were randomly divided in to two main group, 1st group act as normal control, 2nd group was add C12( mixed short and medium fatty acid) in drinking water for 3 day each 8 day at 11, 22 and 33 days age. Blood sample were collected before and after taking C12 treatment for biochemical examination. Supplementation of C12 caused decrease in serum level of AST, ALT, glucose, cholesterol, triglyceride, and pro-inflammatory cytokines as IL-6, increase HDL and total protein. Evaluation of antimicrobial activity of C12.

Screening of single or combined administration of 9 probiotics to reduce ammonia emissions from laying hens.

The effects of single/combined administration of 9 probiotics on ammonia (NH3) emissions during in vitro fermentation of the caecal contents of laying hens were studied. Not all of the probiotics reduced NH3 emissions. Pichia farinose, Bacillus coagulans, Lactobacillus plantarum, Pichia guilliermondii, and Bacillus subtilis reduced NH3 production by approximately 35.1 to 39%. Compared with the control group, the greatest NH3 inhibition was achieved via the combined application of P. guilliermondii, B. subtilis, and L. plantarum at 1:2:1, resulting in a 46% reduction. Effective probiotics use decreased crude protein digestibility, pH, ammonium nitrogen, valerate levels, and urease and uricase activity, but increased urea, purine trione, nitrate nitrogen, total volatile fatty acids, and acetate levels. The relative abundance of the bacteria responsible for fermenting carbohydrates to produce short fatty acids was increased. Under different treatments, the KEGG Orthology (KO) metabolic pathways of NH3 production and utilization were diverse. Hence, the application of probiotics to control NH3 emissions is dependent on the types and combined ratio of the organisms involved.

CHRONIC LYMPHOCYTIC LEUKAEMIA RELIES ON LIPID SCAVENGING AND SYNTHESIS AS AN ENERGY SOURCE

Dysregulation of cancer cell bioenergetics is one of the hallmarks of cancer. The Warburg effect is one such documented change. However, glucose metabolism is not universally increased in cancer cells. Uptake of 18F-FDG in chronic lymphocytic leukemia (CLL) fails as a marker of proliferation and whilst the underlying reason is poorly understood it suggests that CLL cells utilize energy sources other than glucose to proliferate. Using genetic, proteomic and lipidomic analyses, complemented with microscopy and nutrient uptake assays the preferred metabolic pathways of CLL cells have been identified. We measured the uptake of fluorescently labelled short, medium and long-chain fatty acids (LCFA) and the glucose analog 2-NBDG by flow cytometry and confocal microscopy. Three CLL lines (MEC1, MEC2, OSU-CLL) prefer LCFA, over short and medium chain and show a low uptake of 2-NBDG. We have also confirmed these findings in primary CLL samples. Using qPCR and western blot analysis we have identified varying levels of LCFA uptake receptors. We found an up-regulation of proteins involved in lipogenesis in quiescent peripheral CLL cells, and an increase in β-oxidation proteins in the proliferative compartment of the lymph node. Together with our morphological examination using electron and confocal microscopy we suggest that peripheral CLL cells scavenge lipids, which are stored in lipid droplets and protected from degradation by a high expression of PLIN proteins. These cells circulate back to the proliferation centres, the lipid droplets are degraded, likely by lipophagy which frees fatty acids for β-oxidation. Our results begin to unravel CLL bioenergetics and dysregulation of cellular metabolism that occurs in this disease. We are now investigating whether the manipulation of these pathways, particularly lipophagy, may represent a novel therapeutic approach in CLL.

Abstract 5299: Role of short chain free fatty acid receptors in colorectal cancer

Abstract One of the well established risk factors for colorectal cancer is dietary profile. A well recognized negative association of dietary fiber with colorectal cancer warrants further understanding of the underlying mechanism. Bacterial fermentation of dietary fibre results in formation of short chain free fatty acids in the gut. There are two receptors for these fatty acids one of which has been implicated in colorectal cancer. Free fatty acid receptor 2 has been associated with development of colorectal adenoma in a mouse model. We analyzed the differential expression of FFAR2 gene in colorectal cancer patients. Further, we generated genetically engineered colorectal cancer cell line with reduced level of expression of these receptors. These engineered cells were found to have enhanced rate of cell proliferation. In order to understand the mechanism of increased proliferation, we explored the involevement of glucose uptake and cAMP pathways. While there was an increased level of glucose uptake in engineered cells, there was no evidence of involvement of Protein kinase A mediated cAMP pathway. Further studies are needed to fully establish the connection between dietary fibre, gut microbiota and colorectal cancer. Citation Format: Amal AlGhamdi, Saeed AlMahri, Maaged AlAkiel, Sameer Mohammad, Mohammad Aziz. Role of short chain free fatty acid receptors in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5299.

Gut bacteria are critical for optimal muscle function: a potential link with glucose homeostasis.

Gut microbiota is involved in the development of several chronic diseases, including diabetes, obesity, and cancer, through its interactions with the host organs. It has been suggested that the cross talk between gut microbiota and skeletal muscle plays a role in different pathological conditions, such as intestinal chronic inflammation and cachexia. However, it remains unclear whether gut microbiota directly influences skeletal muscle function. In this work, we studied the impact of gut microbiota modulation on mice skeletal muscle function and investigated the underlying mechanisms. We determined the consequences of gut microbiota depletion after treatment with a mixture of a broad spectrum of antibiotics for 21 days and after 10 days of natural reseeding. We found that, in gut microbiota-depleted mice, running endurance was decreased, as well as the extensor digitorum longus muscle fatigue index in an ex vivo contractile test. Importantly, the muscle endurance capacity was efficiently normalized by natural reseeding. These endurance changes were not related to variation in muscle mass, fiber typology, or mitochondrial function. However, several pertinent glucose metabolism markers, such as ileum gene expression of short fatty acid chain and glucose transporters G protein-coupled receptor 41 and sodium-glucose cotransporter 1 and muscle glycogen level, paralleled the muscle endurance changes observed after treatment with antibiotics for 21 days and reseeding. Because glycogen is a key energetic substrate for prolonged exercise, modulating its muscle availability via gut microbiota represents one potent mechanism that can contribute to the gut microbiota-skeletal muscle axis. Taken together, our results strongly support the hypothesis that gut bacteria are required for host optimal skeletal muscle function.

Chemogenetics defines receptor-mediated functions of short chain free fatty acids.

Differentiating actions of short chain fatty acids (SCFAs) at free fatty acid receptor 2 (FFA2) from other free fatty acid-responsive receptors and from non-receptor-mediated effects has been challenging. Using a novel chemogenetic and knock-in strategy, whereby an engineered variant of FFA2 (FFA2-DREADD) that is unresponsive to natural SCFAs but is instead activated by sorbic acid replaced the wild-type receptor, we determined that activation of FFA2 in differentiated adipocytes and colonic crypt enteroendocrine cells of mouse accounts fully for SCFA-regulated lipolysis and release of the incretin glucagon-like peptide-1 (GLP-1), respectively. In vivo studies confirmed the specific role of FFA2 in GLP-1 release and also demonstrated a direct role for FFA2 in accelerating gut transit. Thereby, we establish the general principle that such a chemogenetic knock-in strategy can successfully define novel G-protein-coupled receptor (GPCR) biology and provide both target validation and establish therapeutic potential of a 'hard to target' GPCR.

Immunomodulatory molecules regulate adhesin gene expression in Staphylococcus aureus: Effect on bacterial internalization into bovine mammary epithelial cells

Staphylococcus aureus is a major pathogen of subclinical bovine mastitis that usually is chronic and recurrent, which has been related to its ability to internalize into bovine mammary epithelial cells (bMECs). Previously, we reported that short and medium fatty acids and cholecalciferol reduce S. aureus internalization into pretreated-bMECs with these molecules suggesting a role as immunomodulatory agents. Hence, we assessed the role of sodium butyrate (NaB), sodium octanoate (NaO) and cholecalciferol on S. aureus adhesin expression and its internalization into bMECs. S. aureus pre-treated 2 h with 0.5 mM or 2 mM NaB showed a reduction in internalization into bMECs (∼35% and ∼55%; respectively), which coincided with a down-regulated expression of clumping factor B (ClfB). Also, the S. aureus internalization reduction by 2 mM NaB (2 h) agreed with a down-regulated expression of sdrC. Moreover, the 2 mM NaB (24 h) pre-treatment induced bacterial internalization (∼3-fold), which was related with an up-regulation of spa, clfB and sdrC genes. Also, NaO (0.25 mM and 1 mM) only reduced S. aureus internalization when bacteria were grown 2 h with this molecule but there was no relationship with adhesin expression. In addition, cholecalciferol (50 nM) reduced bacteria internalization at similar levels (∼50%) when bacteria were grown 2 and 24 h in broth supplemented with this compound, which correlated with spa and sdrC mRNA expression down-regulated at 2 h, and fnba and clfB mRNA expression decreased at 24 h. In conclusion, our data support the fact that fatty acids and cholecalciferol regulate adhesin gene expression as well as bacteria internalization in nonprofessional phagocytic cells, which may lead to development of anti-virulence agents for control of pathogens.

Zwitterionic polymeric ionic liquid-based sorbent coatings in solid phase microextraction for the determination of short chain free fatty acids

Five different zwitterionic sorbent coatings based on polymeric ionic liquids (PILs) were developed by the on fiber UV co-polymerization of the zwitterionic monomers 1-vinyl-3-(alkylsulfonate)imidazolium or 1-vinyl-3-(alkylcarboxylate)imidazolium and different dicationic ionic liquid (IL) crosslinkers. The developed sorbent coatings were applied in headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry for the determination of short chain free fatty acids in wine. The sorbent coatings were found to extract these analytes via a non-competitive extraction mechanism. The methodology was optimized for the two best zwitterionic PIL coatings and compared to the commercially-available carboxen/polydimethylsiloxane (CAR/PDMS) and polyacrylate (PA) fibers. The sorbent coating based on the 1-vinyl-3-(propanesulfonate)imidazolium IL (Fiber 1) was more sensitive than PA while providing similar limits of detection to CAR/PDMS for the determination of analytes in a diluted synthetic wine sample. At the same time, Fiber 1 required lower extraction times (only 20 min versus 60 min for CAR/PDMS and 40 min for PA), exhibited higher reproducibility (with relative standard deviation lower than 8.9% for a spiked level of 7 µM) and was more tolerant to ethanol present within the sample. The zwitterionic PILs were also applied for the analysis of red wine, and the results were in agreement with those obtained for CAR/PDMS. The analytes were detected and quantified in the concentration range from 0.18 ± 0.03 mg L−1 to 4.8 ± 0.9 mg L−1, depending on the analyte and fiber.

Intake of individual fatty acids and risk of prostate cancer in the European prospective investigation into cancer and nutrition.

The associations of individual dietary fatty acids with prostate cancer risk have not been examined comprehensively. We examined the prospective association of individual dietary fatty acids with prostate cancer risk overall, by tumor subtypes, and prostate cancer death. 142,239 men from the European Prospective Investigation into Cancer and Nutrition who were free from cancer at recruitment were included. Dietary intakes of individual fatty acids were estimated using center‐specific validated dietary questionnaires at baseline and calibrated with 24‐h recalls. Multivariable Cox regression models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). After an average follow‐up of 13.9 years, 7,036 prostate cancer cases and 936 prostate cancer deaths were ascertained. Intakes of individual fatty acids were not related to overall prostate cancer risk. There was evidence of heterogeneity in the association of some short chain saturated fatty acids with prostate cancer risk by tumor stage (p heterogeneity < 0.015), with a positive association with risk of advanced stage disease for butyric acid (4:0; HR1SD = 1.08; 95%CI = 1.01–1.15; p‐trend = 0.026). There were no associations with fatal prostate cancer, with the exception of a slightly higher risk for those who consumed more eicosenoic acid (22:1n‐9c; HR1SD = 1.05; 1.00–1.11; p‐trend = 0.048) and eicosapentaenoic acid (20:5n‐3c; HR1SD = 1.07; 1.00–1.14; p‐trend = 0.045). There was no evidence that dietary intakes of individual fatty acids were associated with overall prostate cancer risk. However, a higher intake of butyric acid might be associated with a higher risk of advanced, whereas intakes of eicosenoic and eicosapentaenoic acids might be positively associated with fatal prostate cancer risk.

A cellulolytic fungal biofilm enhances the consolidated bioconversion of cellulose to short chain fatty acids by the rumen microbiome

The ability of the multispecies biofilm membrane reactors (MBM reactors) to provide distinguished niches for aerobic and anaerobic microbes at the same time was used for the investigation of the consolidated bioprocessing of cellulose to short chain fatty acids (SCFAs). A consortium based consolidated bioprocess (CBP) was designed. The rumen microbiome was used as the converting microbial consortium, co-cultivated with selected individual aerobic fungi which formed a biofilm on the tubular membrane flushed with oxygen. The beneficial effect of the fungal biofilm on the process yields and productivities was attributed to the enhanced cellulolytic activities compared with those achieved by the rumen microbiome alone. At 30 °C, the MBM system with Trichoderma reesei biofilm reached a concentration 39% higher (7.3 g/L SCFAs), than the rumen microbiome alone (5.1 g/L) using 15 g/L crystalline cellulose as the substrate. Fermentation temperature was crucial especially for the composition of the short chain fatty acids produced. The temperature increase resulted in shorter fatty acids produced. While a mixture of acetic, propionic, butyric, and caproic acids was produced at 30 °C with Trichoderma reesei biofilm, butyric and caproic acids were not detected during the fermentations at 37.5 °C carried out with Coprinopsis cinerea as the biofilm forming fungus. Apart from the presence of the fungal biofilm, no parameter studied had a significant impact on the total yield of organic acids produced, which reached 0.47 g of total SCFAs per g of cellulose (at 30 °C and at pH 6, with rumen inoculum to total volume ratio equal to 0.372).

Nutritional and Microbiological Composition of Serra Estrela Cheese: A Paradigm to Overcome

Background: Milk and dairy products are an excellent source of well-balanced nutrients with multiple uses as a snack, dessert or food ingredient. Serra Estrela cheese, a traditional variety manufactured in the centre region of Portugal, is part of the mankind´s ancient cultural heritage, made from raw sheep milk it is assumed as an iconic gourmet cheese, when compared with other Portuguese cheeses. This work intended to monitor the manufacturing process along the period of production, to evaluate the factors that are decisive for the reproducibility of Serra Estrela cheese in geographical and temporal terms, as well as to achieve the knowledge of the Serra Estrela cheese lipid nutritional characteristics. Methods: Twenty-four Serra Estrela cheese samples originating from representative cheese producers of the region were analysed for their nutritional characteristics, such as moisture, fat, protein and salt, using the FT-NIR (fourier-transform near infrared spectroscopy) technique as an expeditious method. A gas chromatography with flame ionization detection (GC-FID) was used to perform the lipid fraction study. Microbiological analyses were performed for Escherichia coli and coagulase-positive Staphylococcus. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS version 23.0). The level of significance was accessed by Tukey’s test considering p-value < 0.05 to be significant. Results: In the cheeses studied, the moisture varied from 46 % to 52 %, the butyric content from 19 to 30 %, the protein content between 19 and 24 % and the salt from 0.9 to 1.8 %. The determinations of Escherichia coli and coagulase-positive Staphylococcus in some Serra Estrela cheeses exceeded the maximum allowed values per law in Portugal. Regarding to the fatty acids profile, there was no obvious tendency observed, but was found a significative amount of short and medium chain saturated fatty acids, as well as polyunsaturated fatty acids. Conclusion: Considering that year 2017 was considered an exceptional year, both in terms of the severe drought and the fires that devastated the region, with repercussions on health and animal production, it is reasonable that some cheeses exceeded the maximum permissible levels of microorganisms. Although there are significantly differences between the total fat and protein content of Serra Estrela cheeses from different producers, relatively to polyunsaturated, ω-3 and ω-6 fatty acids fractions, all cheese producers are very homogeneous. This work was extremely important for an initial evaluation of the Portuguese Serra Estrela cheese production in 17/18 and for the design of future experimental work.

Volatile Fatty Acid Production from Anaerobic Digestion of Organic Residues.

Short chain volatile fatty acids (VFAs) from acetic acid (C2) to valeric acid (C5) are important starting chemicals for chemical industry. The production of VFAs from rejected resources (organic residues) using self-sustaining technologies has an exciting potential in supporting the US chemical industry to achieve the goal that 20% of chemicals produced in the USA will be bio-based. Acidogenic anaerobic digestion as a robust, well-established, and versatile biological technology can be applied as an alternative approach for the valorization of organic residues (municipal, agricultural, and industrial wastes) by the production of VFAs. In a typical acidogenic anaerobic digestion operation, residue type, pretreatment, reactor operation, and VFA recovery are the key factors that influence VFA production. This chapter discusses these factors and provides an experimental approach of VFA production from organic residues.

Sodium Butyrate Ameliorates Streptozotocin-Induced Type 1 Diabetes in Mice by Inhibiting the HMGB1 Expression.

Type 1 diabetes (T1D) is an autoimmune disease characterized by the immune cell-mediated progressive destruction of pancreatic β-cells. High-mobility group box 1 protein (HMGB1) has been recognized as a potential immune mediator to enhance the development of T1D. So we speculated that HMGB1 inhibitors could have anti-diabetic effect. Sodium butyrate is a short fatty acid derivative possessing anti-inflammatory activity by inhibiting HMGB1. In the current study, we evaluated the effects of sodium butyrate in streptozotocin (STZ)-induced T1D mice model. Diabetes was induced by multiple low-dose injections of STZ (40 mg/kg/day for 5 consecutive days), and then sodium butyrate (500 mg/kg/day) was administered by intraperitoneal injection for 7 consecutive days after STZ treatment. Blood glucose, incidence of diabetes, body weight, pancreatic histopathology, the amounts of CD4+T cell subsets, IL-1β level in serum and pancreatic expressions levels of HMGB1, and NF-κB p65 protein were analyzed. The results showed that sodium butyrate treatment decreased blood glucose and serum IL-1β, improved the islet morphology and decreased inflammatory cell infiltration, restored the unbalanced Th1/Th2 ratio, and down-regulated Th17 to normal level. In addition, sodium butyrate treatment can inhibit the pancreatic HMGB1 and NF-κB p65 protein expression. Therefore, we proposed that sodium butyrate should ameliorate STZ-induced T1D by down-regulating NF-κB mediated inflammatory signal pathway through inhibiting HMGB1.

Bivalent Ligand UDCA-LPE Inhibits Pro-Fibrogenic Integrin Signalling by Inducing Lipid Raft-Mediated Internalization.

Ursodeoxycholyl lysophosphatidylethanolamide (UDCA-LPE) is a synthetic bile acid-phospholipid conjugate with profound hepatoprotective and anti-fibrogenic functions in vitro and in vivo. Herein, we aimed to demonstrate the inhibitory effects of UDCA-LPE on pro-fibrogenic integrin signalling. UDCA-LPE treatment of human embryonic liver cell line CL48 and primary human hepatic stellate cells induced a non-classical internalization of integrin β1 resulting in dephosphorylation and inhibition of SRC and focal adhesion kinase (FAK). Signalling analyses suggested that UDCA-LPE may act as a heterobivalent ligand for integrins and lysophospholipid receptor1 (LPAR1) and co-immunoprecipitation demonstrated the bridging effect of UDCA-LPE on integrin β1 and LPAR1. The disruption of either the UDCA-moiety binding to integrins by RGD-containing peptide GRGDSP or the LPE-moiety binding to LPAR1 by LPAR1 antagonist Ki16425 reversed inhibitory functions of UDCA-LPE. The lack of inhibitory functions of UDCA-PE and UDCA-LPE derivatives (14:0 and 12:0, LPE-moiety containing shorter fatty acid chain) as well as the consistency of the translocation of UDCA-LPE and integrins, which co-fractionated with LPE but not UDCA, suggested that the observed UDCA-LPE-induced translocation of integrins was mediated by LPE endocytic transport pathway.

High-level production of short branched-chain fatty acids from waste materials by genetically modified Bacillus licheniformis

Short branched-chain fatty acids (SBCFAs) are multi-functional platform chemicals used in many fields. Currently, SBCFAs are produced mainly by chemical synthesis, which is high cost and lead to environmental pollution. The aim of this study was to achieve high-level production of SBCFAs from waste materials, bean dreg and crude glycerol. The Bacillus licheniformis DWc9n∗ was genetically modified by overexpression of SBCFAs synthesis genes via replacement of native promoter of bkd operon, the mutant strain DWc9n∗-PbacA produced 4.68 g/L of SBCFAs, increasing by 1.98-fold compared to wild-type strain. SBCFAs concentration was further increased to 7.85 g/L through process optimization. In a 5-L batch fermenter, the mutant showed SBCFAs production with high concentration (8.37 g/L) and productivity (0.20 g/L/h), which is the highest level of SBCFAs production based on low-value substrates fermentation. This is the first study describing efficient SBCFAs production by the modified B. licheniformis strain from bean dreg and crude glycerol.

Isolation and structural elucidation of pelgipeptin E, a novel pore-forming pelgipeptin analog from Paenibacillus elgii with low hemolytic activity.

Pelgipeptins are cyclic lipopeptides composed of nine amino acids and a short fatty acid chain. In the present study, we report a novel pelgipeptin peptide that was isolated from Paenibacillus elgii BC34-6 and named pelgipeptin E (PGP-E). The molecular mass of PGP-E was 1072 Da as determined by liquid chromatography-mass spectrometry and the amino acid sequence was elucidated by tandem mass spectrometry. The complete molecular structure of PGP-E was characterized using 2D NMR spectroscopy. PGP-E consisted of a cyclic peptide backbone of Dab1-Val2-Dab3-Phe4-Leu5-Dab6-Val7-Leu8-Ser9 and a lipid chain (-CH2CH2CH3). PGP-E had broad antimicrobial activity against gram-negative and -positive bacteria, including methicillin-resistant Staphylococcus aureus strains. Furthermore, the mode of action of PGP-E was investigated using calcein dye leakage and membrane depolarization assays, which suggest that PGP-E acts via a membrane-active mechanism. The hemolytic activity of PGP-E was significantly lower than that of melittin, a well-known membrane-active peptide derived from bee venom. These results suggest that PGP-E is a potential candidate in the development of new peptide antibiotics.

A metagenomic analysis of the camel rumen\u2019s microbiome identifies the major microbes responsible for lignocellulose degradation and fermentation

BackgroundThe diverse microbiome present in the rumen of ruminant animals facilitates the digestion of plant-based fiber. In this study, a shotgun metagenomic analysis of the microbes adhering to plant fiber in the camel rumen was undertaken to identify the key species contributing to lignocellulose degradation and short chain volatile fatty acids (VFA) fermentation.ResultsThe density of genes in the metagenome encoding glycoside hydrolases was estimated to be 25 per Mbp of assembled DNA, which is significantly greater than what has been reported in other sourced metagenomes, including cow rumen. There was also a substantial representation of sequences encoding scaffoldins, dockerins and cohesins, indicating the potential for cellulosome-mediated lignocellulose degradation. Binning of the assembled metagenome has enabled the definition of 65 high-quality genome bins which showed high diversity for lignocellulose degrading enzymes. Species associated to Bacteroidetes showed a high proportion of genes for debranching and oligosaccharide degrading enzymes, while those belonging to Firmicutes and Fibrobacteres were rich in cellulases and hemicellulases and thus these lineages were probably the key for ensuring the degradation of lignocellulose. The presence of many “polysaccharide utilization loci” (PULs) in Bacteroidetes genomes indicates their broad substrate specificity and high potential carbohydrate degradation ability. An analysis of VFA biosynthesis pathways showed that genes required for the synthesis of acetate were present in a range of species, except for Elusimicrobiota and Euryarchaeota. The production of propionate, exclusively via the succinate pathway, was carried out by species belonging to the phyla Bacteroidetes, Firmicutes, Spirochaetes and Fibrobacteres. Butyrate was generated via the butyrylCoA: acetate CoA-transferase pathway by Bacteroidetes and Lentisphaerae species, but generally via the butyrate kinase pathway by Firmicutes species.ConclusionThe analysis confirmed the camel rumen’s microbiome as a dense and yet largely untapped source of enzymes with the potential to be used in a range of biotechnological processes including biofuel, fine chemicals and food processing industries.

Effect of Beta Cyclodextrin on the Reduction of Cholesterol in Ewe's Milk Manchego Cheese.

Beta-cyclodextrin (β-CD) is a cyclic oligosaccharide consisting of seven glucose units and is produced from starch using cyclodextrin glycotransferase enzymes to break the polysaccharide chain and forming a cyclic polysaccharide molecule. The use of β-CD in food research for reduction of cholesterol is increasing due to its affinity for non-polar molecules such as cholesterol. The aim of this study was to evaluate the feasibility of using β-CD in cholesterol removal from pasteurized ewe’s milk Manchego cheese and evaluate the effect on the main components of the milk, lipids, and flavor characteristics. Approximately 97.6% cholesterol reduction was observed in the cheese that was treated using β-CD. Physicochemical properties (fat, moisture and protein) were not changed by the β-CD treatment, except the soluble nitrogen and non-protein nitrogen that showed slight differences after the treatment. The amount of the different components of the lipid fraction (fatty acids, triglycerides and phospholipids) were similar in cheeses treated and not treated with β-CD. Flavor compound and short chain free fatty acids were not mostly significantly influenced by the effect of the β-CD. β-CD molecules are edible and nontoxic and as a result they can be used safely for cholesterol removal processing in cheese manufacturing. Therefore, the present study suggests that β-CD treatment is an effective process for cholesterol removal from Manchego cheese while preserving its properties.