Fatty Acid Methyl Ester Analysis Research Articles

The Influence of Soy Isoflavones and Soy Isoflavones with Inulin on Kidney Morphology, Fatty Acids, and Associated Parameters in Rats with and without Induced Diabetes Type 2.

Diabetes mellitus resulting from hyperglycemia stands as the primary cause of diabetic kidney disease. Emerging evidence suggests that plasma concentrations of soy isoflavones, substances with well-established antidiabetic properties, rise following supplemental inulin administration. The investigation encompassed 36 male Sprague-Dawley (SD) rats segregated into two cohorts: non-diabetic and diabetic, induced with type 2 diabetes (high-fat diet + two intraperitoneal streptozotocin injections). Each cohort was further divided into three subgroups (n = 6): control, isoflavone-treated, and isoflavone plus inulin-treated rats. Tail blood glucose and ketone levels were gauged. Upon termination, blood samples were drawn directly from the heart for urea, creatinine, and HbA1c/HbF analyses. One kidney per rat underwent histological (H-E) and immunohistochemical assessments (anti-AQP1, anti-AQP2, anti-AVPR2, anti-SLC22A2, anti-ACC-alpha, anti-SREBP-1). The remaining kidney underwent fatty acid methyl ester analysis. Results unveiled notable alterations in water intake, body and kidney mass, kidney morphology, fatty acids, AQP2, AVPR2, AcetylCoA, SREBP-1, blood urea, creatinine, and glucose levels in control rats with induced type 2 diabetes. Isoflavone supplementation exhibited favorable effects on plasma urea, plasma urea/creatinine ratio, glycemia, water intake, and kidney mass, morphology, and function in type 2 diabetic rats. Additional inulin supplementation frequently modulated the action of soy isoflavones.

Curtobacterium salicis sp. nov., isolated from willow tree stems in Washington state.

Curtobacterium sp. strain WW7 is a Gram-positive, non-motile, orange rod-shaped bacterium isolated from branches of wild willow (Salix sitchensis) trees. The WW7T strain has optimum growth in the temperature range between 25 and 30°C, a pH range of 6-7.7, and tolerates up to 5.5% (w/v) of NaCl. The genome sequencing of strain WW7T revealed a genome size of approximately 3.8 Mbp and a G + C content of 71.3mol%. The phylogenomic analyses support the WW7T affiliation to a novel Curtobacterium lineage, with Curtobacterium herbarum being the closest type-strain. Chemotaxonomic analysis indicates that the carbon sources assimilation profile of strain WW7T was similar to the type strains, i.e. Curtobacterium luteum, Curtobacterium albidum, and Curtobacterium flaccumfaciens, while no assimilation of the organic acids succinate, alpha-ketobutyrate, mono methyl-succinate, and lactate was observed. Finally, fatty acid methyl ester analysis identifies anteiso-C15:0 and anteiso-C17:0 as major cellular fatty acids which is a common feature for members of the Curtobacterium genus. Based on the results of phylogenomic and chemotaxonomic analyses, strain WW7T represents a novel Curtobacterium lineage, for which the name Curtobacterium salicis sp. nov. is proposed. The type strain is WW7T (DSM 34805T-NRRL B-68078T).

Genetic and chemical control of tuberculostearic acid production in Mycobacterium avium subspecies paratuberculosis.

Tuberculostearic acid (TBSA) is a fatty acid unique to mycobacteria and some corynebacteria and has been studied due to its diagnostic value, biofuel properties, and role in membrane dynamics. In this study, we demonstrate that TBSA production can be abrogated either by addition of pivalic acid to mycobacterial growth cultures or by a bfaA gene knockout encoding a flavin adenine dinucleotide (FAD)-binding oxidoreductase. Mycobacterium avium subspecies paratuberculosis (Map) growth and TBSA production were inhibited in 0.5-mg/mL pivalic acid-supplemented cultures, but higher concentrations were needed to have a similar effect in other mycobacteria, including Mycobacterium smegmatis. While Map C-type strains, isolated from cattle and other ruminants, will produce TBSA in the absence of pivalic acid, the S-type Map strains, typically isolated from sheep, do not produce TBSA in any condition. A SAM-dependent methyltransferase encoded by bfaB and FAD-binding oxidoreductase are both required in the two-step biosynthesis of TBSA. However, S-type strains contain a single-nucleotide polymorphism in the bfaA gene, rendering the oxidoreductase enzyme vestigial. This results in the production of an intermediate, termed 10-methylene stearate, which is detected only in S-type strains. Fatty acid methyl ester analysis of a C-type Map bfaA knockout revealed the loss of TBSA production, but the intermediate was present, similar to the S-type strains. Collectively, these results demonstrate the subtle biochemical differences between two primary genetic lineages of Map and other mycobacteria as well as explain the resulting phenotype at the genetic level. These data also suggest that TBSA should not be used as a diagnostic marker for Map.IMPORTANCEBranched-chain fatty acids are a predominant cell wall component among species belonging to the Mycobacterium genus. One of these is TBSA, which is a long-chain middle-branched fatty acid used as a diagnostic marker for Mycobacterium tuberculosis. This fatty acid is also an excellent biolubricant. Control of its production is important for industrial purposes as well as understanding the biology of mycobacteria. In this study, we discovered that a carboxylic acid compound termed pivalic acid inhibits TBSA production in mycobacteria. Furthermore, Map strains from two separate genetic lineages (C-type and S-type) showed differential production of TBSA. Cattle-type strains of Mycobacterium avium subspecies paratuberculosis produce TBSA, while the sheep-type strains do not. This important phenotypic difference is attributed to a single-nucleotide deletion in sheep-type strains of Map. This work sheds further light on the mechanism used by mycobacteria to produce tuberculostearic acid.

Fatty Acid Methyl Ester Profiling of Californian Xylella fastidiosa Strains

Xylella fastidiosa ssp. fastidiosa ( Xff) is the causal agent of Pierce's disease of grapevine, a management-intensive and potentially deadly disease. However, different stains and other subspecies, such as Xylella fastidiosa ssp. multiplex ( Xfm), exist in the same regions and vary in capacity to cause disease. All strains differ in the fatty acids that comprise cell membranes, as these allow adaptations to specific host microenvironments. Therefore, studies were initiated to observe the fatty acid profiles of different Californian Xf isolates via fatty acid methyl ester (FAME) analysis. Observations revealed that the four Xff strains had similar FAME profiles that were distinct from those of the three Xfm strains, even in isolates that originated from the same host plant species. These data show consistent differences between Xff and Xfm strains and demonstrate the potential that FAME profiling has for Xylella subspecies identification of novel isolates. [Formula: see text] The author(s) have dedicated the work to the public domain under the Creative Commons CC0 “No Rights Reserved” license by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law, 2024.

Bicarbonate-assisted microalgae cultivation for drinking water RO reject recycling and bioproduct generation

This study undrapes a microalgae-mediated approach for recycling drinking water reverse osmosis (RO) reject with bicarbonate supplementation. Among the tested strains, Chlorella pyrenoidosa exhibited a significantly (p ≤ 0.05) higher biomass growth (760.81 ± 34.24 mg L−1) at 4.0 g L−1 bicarbonate in RO reject. Whereas Scenedesmus sp. showed the maximum biomass yield of 1041.81 ± 33.32 mg L−1 in RO reject without bicarbonate. Moreover, bicarbonate in RO reject promoted biofuel precursor synthesis, with Scenedesmus obliquus and Chlorella sorokiniana acquiring maximum carbohydrate (339.41 ± 13.68 mg L−1) and lipid (1453.57 ± 44.29 mg L−1) yields at 0.5 and 1.0 g L−1 bicarbonate, respectively. The fatty acid methyl ester (FAME) and theoretical methane potential (TMP) analyses showed improved biodiesel quality and biogas yield from bicarbonate-supplemented RO reject-grown microalgal biomass. Thus, the present findings inferred that bicarbonate supplementation to RO reject could be an economically feasible approach for RO reject recycling and microalgae-mediated resource recovery.

Direct and rapid profiling of triacylglycerols in extra virgin olive oil using UHPLC-MS/MS

Extra virgin olive oil (EVOO) prices reached record levels in 2023, due to the decline in global production, mainly linked to drought in the Mediterranean. Without effective controls, the already widespread fraud in this sector will irrevocably worsen. However, the reliability of the current standard method (CSM) for controlling the authenticity of EVOO has been questioned. Besides, authors have recently called for the replacement of certain steps to reduce analysis time and solvent consumption. In fact, CSM based on HPLC-RID analysis of triacylglycerols (TAGs) and GC analysis of fatty acid methyl esters (FAMEs) is tedious and very time consuming. Here, we optimized and validated a UHPLC-APCI-MS/MS method capable of unambiguously identifying 33 TAGs in EVOO in less than 6 min. The limit of detection calculated for the available TAG standards is between 0.3 and 2.5 ng/ml (0.02 ng–0.13 ng of injected quantity). The linearity of the method in real samples is satisfactory (r2 > 0.99, n = 6) for 27 TAGs with an average area greater than 0.04 %. In real samples, the between-run precision (RSD %) for 29 TAGs with mean area greater than 0.02% does not exceed 11.6%, provided that the injected amount is equal to or greater than 4 μg of EVOO sample. The application of this method to eleven EVOO samples, including a control sample from the International Olive Council, and the processing of the data with a PCA model allow their fine discrimination according to their TAG profiles. In addition to eliminating the GC step of FAME analysis, the high productivity of the proposed method significantly reduces the cost of this essential control step compared to CSM.

Microbial community response to cover cropping varied with time after termination

AbstractThis study evaluates cover crop (CC) effects on microbial community structure in a winter wheat–sorghum–fallow rotation with pea, oat, and canola; mixtures of pea and oat; pea and canola; pea, oat, and canola; and six species mixture (SSM) of pea, oat, canola, hairy vetch, forage radish, and barley as CCs, and fallow as treatments. Soil microbial community structure was analyzed at CC termination (phase I), 36 days (phase II), and a year (phase III) after termination using an ester‐linked fatty acid methyl ester analysis. Total microbial biomass (TMB) under oats was significantly greater than under canola (by 47%) in phase I (p ≤ 0.05). The TMB was >48% under pea, pea + canola, and SSM, and arbuscular mycorrhizal fungi was 70%–93% more under pea, canola, and their mixtures than fallow in phase II. While microbial abundance varied with CCs at and after 36 days post‐termination, these effects did not persist for a year. Long fallow period after cropping or cover cropping appears detrimental to microbial community proliferation.

SAT265 Stearoyl CoA Desaturase Knockdown Increases Saturated And Monounsaturated Fatty Acid Concentrations In SDHB KD Cells But Not In hPheo1 Wild-type Progenitor Cells

Abstract Disclosure: H.K. Ghayee: Other; Self; Royalties form the University of Texas Southwestern Medical Center. N. Bala: None. Y. Xu: None. S.G. Tevosian: None. M. Kozuch: None. N.D. Denslow: None. A.A. Alli: None. Introduction: Pheochromocytoma and paraganglioma (PPGL) patients with mutations in the succinate dehydrogenase B subunit (SDHB) frequently develop metastatic lesions and have a poor prognosis. The stearoyl-CoA desaturase 1 (SCD1) protein plays an important role in lipid metabolism. SCD1 inhibitors have shown great potential as new treatments for various diseases including cancer. Hypothesis: siRNA mediated knockdown of SCD1 compared to non-targeting siRNA would result in differences in the concentrations of saturated fatty acids and monounsaturated fatty acids in SDHB KD cells compared to hPheo1 wild-type (WT) progenitor cells. Methods: Fatty acid concentrations were assessed by fatty acid methyl ester (FAME) analysis. SCD1 expression was assessed by quantitative polymerase chain reaction (qPCR) and Western blotting analysis. Results: Analyses showed a significant decrease in SCD1 in SDHB KD cells compared to hPheo1 WT cells. Fatty acid methyl ester analysis showed the concentrations of the saturated fatty acids myristic acid, palmitic acid, and stearic acid, and the monounsaturated fatty acids palmitoleic acid and oleic acid are increased at least 2-fold in SDHB KD cells transfected with SCD1 siRNA compared to non-targeting siRNA. Conclusions: Fatty acid changes noted in hPheo1 SDHB KD cells were not seen in hPheo1 WT cells after siRNA mediated knockdown of SCD1. This suggests that SDHB deficiency and loss of FADH2 production interacts specifically with lipid desaturation pathways. Presentation: Saturday, June 17, 2023

Amygdalobacter indicium gen. nov., sp. nov., and Amygdalobacter nucleatus sp. nov., gen. nov.: novel bacteria from the family Oscillospiraceae isolated from the female genital tract.

Four obligately anaerobic Gram-positive bacteria representing one novel genus and two novel species were isolated from the female genital tract. Both novel species, designated UPII 610-JT and KA00274T, and an additional isolate of each species were characterized utilizing biochemical, genotypic and phylogenetic analyses. All strains were non-motile and non-spore forming, asaccharolytic, non-cellulolytic and indole-negative coccobacilli. Fatty acid methyl ester analysis for UPII 610-JT and KA00274T and additional isolates revealed C16 : 0, C18 : 0, C18:1ω9c and C18:2ω6,9c to be the major fatty acids for both species. UPII 610-JT had a 16S rRNA gene sequence similarity of 99.4 % to an uncultured clone sequence (AY724740) designated as Bacterial Vaginosis Associated Bacterium 2 (BVAB2). KA00274T had a 16S rRNA gene sequence similarity of 96.5 % to UPII 610-JT. Whole genomic DNA mol% G+C content was 42.2 and 39.3 % for UPII 610-JT and KA00274T, respectively. Phylogenetic analyses indicate these isolates represent a novel genus and two novel species within the Oscillospiraceae family. We propose the names Amygdalobacter indicium gen. nov., sp. nov., for UPII 610-JT representing the type strain of this species (=DSM 112989T, =ATCC TSD-274T) and Amygdalobacter nucleatus gen. nov., sp. nov., for KA00274T representing the type strain of this species (=DSM 112988T, =ATCC TSD-275T).

Normolipidic diet containing deep-fried saturated and unsaturated fatty acids rich edible oils promotes metabolic dysregulation and inflammatory microenvironment in Wistar rats.

Deleterious health impacts of high dietary intake of deep-fried edible oils have been reported however, their health impacts at normal dietary levels are yet to be evaluated. This study investigated the influence of prolonged consumption of thermally oxidised long-chain saturated and unsaturated edible oils on metabolic dysregulation and inflammation. The thermally oxidised oils used in the study possess higher p-anisidine values and free fatty acid contents compared to unoxidised oils. Fourier transform infrared spectroscopy and fatty acid methyl ester analysis confirmed the presence of free fatty acids, hydroperoxides, and aldehydes, formed during thermal oxidation. The study analysed the effects of dietary intake of 5% sunflower oil, palm oil, and their thermally-oxidised forms in male Wistar rats for six months. Unoxidised and thermally oxidised palm oil-fed animals experienced metabolic syndrome with obesity-associated inflammatory changes. However, sunflower oil-fed animals exhibited increased inflammation, as evidenced by enhanced C-reactive protein, IL-6, and lipoprotein-associated phospholipase A2 activity and hepatosteatosis condition. This study indicates that prolonged consumption of thermally oxidised oil leads to the dysregulation of carbohydrate and lipid metabolism andpromotes inflammatory microenvironment in Wistar rats that may contribute to metabolic syndrome associated with obesity and hepatic steatosis.

Mixotrophic Cultivation of Chlorella vulgaris on Banana Waste for Biodiesel Production

Environmentally friendly biofuels are currently produced in large quantities using algal lipids. Objective: To perform mixotrophic cultivation of Chlorella vulgaris on Banana Waste for Biodiesel Production. Methods: Banana waste was treated with acid/alkaline, ground, and sun dried. The resultant hydrolysate was used into studies comparing photoautotrophic and mixotrophic conditions in microalgae culture. When biomass productivity and lipid content were measured. For mono-unsaturated, poly-unsaturated, and saturated forms, the lipid content differed. The research used analytical methods for fatty acid methyl ester analysis, such as GC-MS. Results: Mixotrophic cultivation exhibited a much higher biomass productivity (135 mg L-1 d-1) than photoautotrophic cultivation (115 mg L-1 d-1). Additionally, mixotrophically raised biomass had a much larger (w/w) lipid content (45%) than photo-autotrophically raised biomass (30 %). Higher amount of polyunsaturated fatty acids (palmitic and oleic acids) was shown by Lipidome. Conclusions: High-quality biofuel might be made possible by the regular availability of polyunsaturated fatty acids (64 mg g-1 of dry biomass) in the lipid contents of mixotrophically produced algal biomass

Biodegradability of bacterial cellulose polymer below the soil and its effects on soil bacteria diversity

The increasing demand for sustainable materials has led to a surge in research on biodegradable polymers. This study evaluated the weight and visual changes of bacterial cellulose (BC) polymers and nylon membranes during an eight-week biodegradation study below soil. Scanning electron microscope (SEM) images were taken to investigate morphological changes from decomposition. Changes in soil microbial communities and the relationship between microbial abundance and BC biodegradation were investigated. BC was produced from the fermentation of coffee kombucha using 15 % d-dextrose C6H12O6 (DE) as the nutrient carbohydrate substrate. BCs were purified with 0.5 mol/L aqueous NaOH solution and 1.5 % (v/v) aqueous NaOCl and then freeze-dried. The biodegradation study was conducted using seedling pots and nylon membrane filters inside a greenhouse over eight weeks, with sample points taken at various intervals. Soil characteristics such as pH, nutrient content, texture, organic matter, and soil moisture were analyzed. Results showed that BC polymers underwent significant weight losses and visual decomposition, while nylon membranes did not show any weight or visual losses. Approximately 75 % of the BC polymers were decomposed by the end of the study. Fatty acid methyl ester (FAMEs) analysis showed increased microbial absolute abundance (nmol/g) for BC treatments over biodegradation time. FAMEs principal component analysis (PCA) ordination plots showed the relative abundance of fungi increased in BC microbial communities suggesting fungi's attraction to cellulose. Soil bacterial DNA analysis revealed the dominance of Proteobacteria for all treatments. PCA plots and Faith-pd index Alpha Diversity results showed significant bacterial community variations for week 2 of the biodegradation study compared to the other weeks. Adonis microbial community Beta Diversity analysis showed significant differences between treatments (p = 0.001). PCA plots also showed a slight differentiation of the bacterial communities with BC compared to bacterial communities with nylon and soil (control). This study confirms that BC is easily decomposed in soil and that its biodegradability is likely driven by fungal communities.

Sampling and Characterization of Bioaerosols in Poultry Houses.

Two poultry Confined Animal Feeding Units (CAFUs), "House A" and "House B", were selected from the TAMU poultry facility for the study, and samples were collected over a five-day period. Bioaerosol sampling was conducted using a Wetted Wall Cyclone (WWC) bioaerosol collector at the two CAFU houses, in which House A housed approximately 720 broiler chickens and roosters, while House B remained unoccupied and served as a reference. Both houses consisted of 24 pens arranged on either side of a central walkway. Bacterial content analysis was conducted using microbial plating, real-time Polymerase Chain Reaction (PCR), and Fatty Acid Methyl Ester (FAME) analysis, while ambient temperature and relative humidity were also monitored. The concentrations of microorganisms in House A showed a highly dynamic range, ranging from 4000 to 60,000 colony forming units (CFU) per cubic meter of air. Second, the WWC samples contained approximately ten-fold more bacterial DNA than the filter samples, suggesting higher levels of viable cells captured by the WWC. Third, significant concentrations of pathogens, including Salmonella, Staphylococcus, and Campylobacter, were detected in the poultry facility. Lastly, the WWC system demonstrated effective functionality and continuous operation, even in the challenging sampling environment of the CAFU. The goal of this study was to characterize the resident population of microorganisms (pathogenic and non-pathogenic) present in the CAFUs and to evaluate the WWC's performance in such an environment characterized by elevated temperature, high dust content, and feathers. This knowledge could then be used to improve understanding microorganism dynamics in CAFUs including the spread of bacterial infections between animals and from animals to humans that work in these facilities, as well as of the WWC performance in this type of environment (elevated temperature, high content of dust and feathers). A more comprehensive understanding can aid in improving the management of bacterial infections in these settings.

Strategy for lipid extraction and transesterification to enhance Chlorella sorokiniana strain BV 12 feedstock utilization

Efficient production and recovery of fatty acid methyl esters (FAMEs) from lipid containing feedstock is the key step of biodiesel production. This enhances the utilization of feedstock and improves the final economics of the process. Currently, direct and indirect transesterification strategies are being employed for biodiesel production from microalgae with few reports of tailoring the process to a specific feedstock. In this study, Chlorella sorokiniana strain BV 12 was grown in modified BG-11 medium and biomass was harvested. This was subjected to different physical, chemical and physico-chemical strategies for increasing the transesterification yield. The transesterified lipid was evaluated for various biodiesel properties like iodine value, saponification value, acid value, peroxide value and cetane number. After harvesting, gravimetric lipid yield of 161.7 mg/g and 4117.5 µg/g of FAME were obtained. Extraction of lipid was dependent on the cell disruption technique as it is accumulated intracellularly as droplets. Sonication resulted in maximum FAME production using either dry (4724.2 µg/g) and wet (4835.8 µg/g) biomass which shows that wet biomass is more suitable for processing. Gravimetric results favour the extraction by sonication showing a 63.22% increase in lipid recovery. Testing of different solvents for extraction showed methanol as most favourable for FAME analysis with acidic catalyst like HCl and H2SO4 giving FAME with better ignition value (∼51, Cetane number).

Isolation and characterization of phosphate-solubilizing bacterium Pantoea rhizosphaerae sp. nov. from Acer truncatum rhizosphere soil and its effect on Acer truncatum growth.

The Acer truncatum Bunge, widely distributed in North China, shows excellent tolerance to low-P soils. However, little information is available on potential phosphate-solubilizing bacterial (PSB) strains from the A. truncatum rhizosphere. The objectives of this work were to isolate and characterize PSB from A. truncatum rhizosphere soil and to evaluate the effect of inoculation with the selected strain on A. truncatum seedlings. The strains were characterized on the basis of phenotypic characteristics, carbon source utilization pattern, fatty acid methyl esters analysis, 16S rRNA gene and the whole-genome sequence. A Gram-negative and rod-shaped bacterium, designated MQR6T, showed a high capacity to solubilize phosphate and produce indole-3-acetic acid (IAA) and siderophores. The strain can solubilize tricalcium phosphate (TCP) and rock phosphate (RP), and the solubilization of TCP was about 60% more effective than RP. Phylogenetic analyses based on the 16S rRNA gene and whole-genome sequences revealed that strain MQR6T formed a distinct phyletic lineage as a new species within the genus Pantoea. The digital DNA-DNA hybridization value between strain MQR6T and the closely related strains was 19.5-23.3%. The major cellular fatty acids were summed feature 3 (C16:1ω7c and/or C16:1ω6c), summed feature 8 (C18:1ω6c and/or C18:1ω7c), C14:0, C16:0, and C17:0 cyclo. Several genes related to IAA production, phosphonate transport, phosphate solubilization and siderophore biogenesis were found in the MQR6T genome. Furthermore, inoculation with the strain MQR6T significantly improved plant height, trunk diameter, dry weight and P accumulation in roots and shoot of A. truncatum seedlings compared to non-inoculated control. These plant parameters were improved even further in the treatment with both inoculation and P fertilization. Our results suggested that MQR6T represented a new species we named Pantoea rhizosphaerae, as a plant growth-promoting rhizobacterium that can solubilize inorganic P and improve growth of A. truncatum seedlings, emerging as a potential strategy to improve A. truncatum cultivation.

Biotechnological product potential of Auxenochlorella protothecoides including biologically active compounds (BACs) under nitrogen stress conditions.

Nitrogen stress can influence microalgae's growth characteristics, and microalgae grown in nitrogen-deficient conditions may produce higher or lower levels of biotechnological products as a result of metabolic changes. In photoautotrophic and heterotrophic cultures, nitrogen limitation has been proven effective in promoting lipid accumulation. In spite of this, no study has demonstrated a significant correlation between lipid content and other biotechnological products such as bioactive compounds (BACs).This research examines a strategy for lipid accumulation as well as the potential production of BACs with antibacterial properties in parallel with that strategy. This concept involved the treatment of the microalga Auxenochlorella protothecoides with low and high concentrations of ammonium (NH4+). This particular experiment reached a maximum lipid content of 59.5% using a 0.8 mM NH4+ concentration, resulting in the yellowing of the chlorophyll levels. Agar diffusion assays were conducted to determine the antibacterial activity of different extracts derived from the biomass when stressed with different levels of nitrogen.Algal extracts prepared by a variety of solvents showed different levels of antibacterial activity against representative strains of both gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria. Among the extracts tested, 500mg/L ethyl acetate extract had the greatest antibacterial activity against Escherichia coli. In order to identify the components responsible for the extract's antibacterial activity, fatty acid methyl ester (FAME) analysis was performed. It has been suggested that the lipid fraction may be a valuable indicator of these activities since some lipid components are known to possess antimicrobial properties. In this regard, it was found that the amount of polyunsaturated fatty acid (PUFA) significantly decreased by 53.4% under the conditions with the highest antibacterial activity observed.

Purification and characterization of a psychrophilic lipase from Serratia marcescens VT 1 and its application in methyl ester synthesis

Lipase from Serratia marcescens VT 1 with a molecular weight of 62 kDa was purified by 9.42 fold with 16.89 % recovery by DEAE Cellulose and Sephadex G-75 columns. The characterization studies showed the optimum temperature and pH were 30 °C and 7, with good stability from 10 to 30 °C and pH 7. The lipase displayed good stability in the presence of metal ions Ca2+ and Na+, surfactants Gum arabic and Triton X-100, inhibitor EDTA, and organic solvents hexane and methanol. The serine inhibitor PMSF reduced lipase activity by 66 %. Vmax and Km kinetic parameters were 35.21 μmol/ml/min and 0.823 mM with p-nitrophenyl palmitate as substrate. The induction of methyl palmitate, methyl stearate, methyl oleate, and methyl linoleate from palm oil was confirmed by fatty acid methyl ester (FAME) analysis. The present study showed that the Serratia marcescens VT 1 lipase is a psychrophilic, neutral, and serine lipase efficacious of methyl esters genesis.

First Report of Bacterial Leaf Spot on Spinach (Spinacia oleracea) Caused by Pseudomonas sp. in South Carolina.

A large grower of Brassica leafy greens and spinach in South Carolina observed a severe outbreak of leaf spot on 150 hectares of spinach (Spinacia oleracea) in Orangeburg County, SC in 2013. The entire field was lost due to the outbreak. Symptoms appeared on 8-week old plants as tan to white necrotic spots with black centers, water-soaking and no discernable chlorotic borders. Lesions varied from 2 mm to 1 cm in diameter and often coalesced to cover >50% of the leaves. Symptomatic spinach plants cv. Vancouver were collected in 2013 from the field. Bacterial streaming was evident from the border of necrotic lesions under magnification. Lesion border regions were excised, surface-disinfested with 0.5% NaOCl, macerated in sterilized distilled water and streaked onto nutrient agar (NA) and Pseudomonas Agar F (PAF). Bacterial growth was observed on NA and PAF; several single colonies were selected and re-streaked onto PAF. Colonies fluoresced blue under UV light after 48 h at 28oC. Two of the strains were subjected to 16S rRNA sequencing (GenBank accessions OM983506 and OM983507) and Fatty Acid Methyl Ester (FAME) analysis (MIDI LABS, Newark, DE). FAME results had a best similarity index (0.788) to Pseudomonas cichorii/viridiflava. The 16S sequences were queried to Pseudomonas type-strains in GenBank resulting in best matches: P. ovata (99.23% identity with 99% coverage) and P. maditerranea (99.04% identity with 100% coverage). Additionally, sequences had 97.33% identity with 100% coverage as a P. cichorii type strain, and only 96.86% identity with 97% coverage as a P. viridiflava type strain. These two strains were tested for pathogenicity on the spinach cv. Vancouver. Bacteria were grown on PAF for 48 h, and a bacterial suspension was prepared with sterile distilled water with the addition of 0.001% Latron (Plant Health Technologies, Boise, ID) and adjusted to an optical density of 0.4 at OD600. Six-week-old plants (eight plants) were sprayed with the bacterial suspension to runoff, placed at 100% relative humidity for 72 h, and then put in a growth chamber at 25oC with a 12 h diurnal light cycle for 10 days. Eight plants of 'Vancouver' were sprayed with water and 0.001% Latron as controls. Both strains were pathogenic on 'Vancouver' and caused symptoms similar to those observed in the field. Symptoms were not observed on negative controls. The same bacterial colonies were recovered from the lesions on inoculated plants, fulfilling Koch's postulates. Comparative rep-PCR analysis using the BOXA1R primer (Versalovic et al. 1994) showed both strains had identical DNA-banding profiles. All identification methods used indicate that this is a different Pseudomonas species from the one reported on spinach in California by Koike et al (2002). The top producers of spinach in SC stopped large-scale production in 2014 as a result of this pathogen. In 2020, due to inability of processors to obtain sufficient quantities of spinach, SC growers again planted the crop. Growers experienced yield losses due to similar symptoms on the crop. BOX-PCR of isolated strains of bacteria from these plants showed a DNA banding pattern similar to the 2013 strains.

Integrating biological and chemical CO2 sequestration using green microalgae for bioproducts generation

Microalgae cultivation is considered an attractive negative emission technology (NET) due to its ability to remove carbon dioxide (CO2) from the atmosphere as well as from flue gases. Moreover, some microalgae can uptake dissolved carbon in the form of bicarbonate (HCO3-) and grow well by removing nutrients from various wastewater effluents without competing with freshwater resources. Conventional carbon mineralization is another NET where carbon is fixed into carbonate minerals such as calcite (CaCO3), magnesite (MgCO3), nesquehonite (MgCO3-3H2O), and nahcolite (NaHCO3), which can be reused in various applications such as construction and cosmetics, and in this case, to supply carbon to microalgae. Previous initial laboratory studies demonstrated the possibility of using metastable carbonates as a source of carbon for biomass growth of the freshwater microalga Scenedesmus obliquus. In this study, we present results from an experimental and modeling work where 100 L open raceway reactors were used to grow an algae polyculture using industrial nitrogen-rich wastewater. In addition, carbonates such as MgCO3-3H2O and sodium carbonate (Na2CO3) were added to the ponds to primarily buffer the pH and maintain it within the acceptable algae physiological values and to provide extra carbon to the cultures. Cultures using BG-11 growth medium and without addition of carbonates were run as controls. Continuous online monitoring of pH, temperature, and dissolved oxygen was performed while nutrients content and dry weight of algae culture were measured offline daily. A mathematical model coupled with geochemistry was implemented to describe the overall process of algae growth, carbonate dissolution, and solution composition. Biomass harvested from the raceway reactors was concentrated and oil and fatty acid methyl esters (FAME) content were determined. Results showed that biomass and oil content obtained were comparable to controls, indicating a successful metabolic-based pH control by the addition of carbonates in the ammonium-based media. Furthermore, FAME analysis revealed different profiles depending on the source of carbon used. Overall, this study suggests that integrating both types of NET strategies can contribute to the reduction of carbon emissions while producing biomass that can be further processed to generate a variety of bioproducts.

The effect of n-hexane as co-solvent in direct trans esterification of Spirulina platensis using microwave

The addition of co-solvent on in situ trans esterification was considered as one of method to improve the extractive process and increase in yield of biodiesel from microalgae. In this study, in situ trans esterification with co-solvent using microwave was studied for improving performance of in situ trans esterification from microalgae. The biodiesel produced from this method was compared with the in situ trans esterification without co-solvent addition. In the optimal reaction conditions (ratio of microalgae to methanol 1:15 w /v; 30 ml of co-solvent and 30 % of H2SO4) at 50 min of reaction time, yield of Fatty Acid Methyl Ester (FAME) produced was 81.04 % compared to only 75,246 % methyl ester produced by in situ trans esterification without co-solvents. The Fatty Acid Methyl Ester Analysis showed the methyl ester profile was a Medium Chain Fatty Acid, MCFA and the largest fatty acid component was dominated by Saturated Fatty Acid, SAFA.