Novel chromatographic purification of succinic acid from whey fermentation broth by anionic exchange resins.

Replacement of the petroleum-based refineries with the biorefinery is regarded as an essential step towards a "zero" waste (circular) economy. Biobased succinic acid (SA) is listed by the United States Department of Energy among the top ten chemicals with the potential to replace chemicals from petroleum synthesis with renewable sources. Purification of bio-based succinic acid from fermentation by-products such as alcohols, formic acid, acetic acid and lactic is a major drawback of fermentative SA production. This study addresses this issue through a novel chromatographic separation using three distinct anionic resins: Amberlite IRA958 Cl (strong base anion exchange resin), Amberlite HPR 900 OH (strong base anion exchange resin) and Amberlyst A21 (week base anion exchange resin). The influence of process variables such as flow rate (0.18 BV/h, 0.42 BV/h and 0.84 BV/h), eluent concentration (1%, 5% and 10% HCl) and temperature (20, 30 and 40 °C) were investigated. The results indicated SA separation efficiency of 76.1%, 69.3% and 81.2% for Amberlyst A21, Amberlite HPR 900 OH and Amberlite IRA958 Cl, respectively. As the regenerant HCl concentration increased from 1 to 10%, calculated succinic acid separation efficiencies decreased from 80.3 to 70.7%. Notably, as the regenerant strength increased from 1 to 10%, the total amount of organic acids desorbed from the resin sharply increased. At operation temperatures of 20, 30 and 40 °C, SA separation efficacies were 81.2%, 73.9% and 76.4%, respectively. The insights from this study will be of great value in design of chromatographic separation systems for organic acids.

Isolated Ascites in a Monochorionic Twin after Fetoscopic Laser Ablation Is Not Necessarily Secondary to Recurrence or Anaemia: Bowel Complications in Twin-to-Twin Transfusion Syndrome after Fetoscopic Laser Ablation.

BACKGROUND/PURPOSE: We report a case study of jejunal atresia and the results of a systematic literature review of all reported cases of bowel complications occurring after fetoscopic laser ablation (FLA) for the treatment of twin-to-twin transfusion syndrome (TTTS). METHODS: A systematic literature review was performed of bowel complications after FLA for TTTS according to PRISMA guidelines. RESULTS: There are 11 published cases of small bowel atresia, 5 cases of necrotising enterocolitis (NEC), and 2 cases with foetal bowel perforations. Recipient twins were more likely to be affected by small bowel atresia (7 recipient and 4 donor cases) and NEC (3 recipient and 2 donor twins). Prenatal ultrasonographic abnormalities were demonstrated in 7 out of 9 cases with bowel atresia and in both cases of bowel perforation. The overall survival rate for neonates with bowel complications after FLA is 72%, but is much lower for co-twins at 22%. The survival rates for jejunoileal atresia and NEC are 91 and 40%, respectively. CONCLUSIONS: It is uncertain as to whether these bowel anomalies are due to bowel ischaemia associated with TTTS, the treatment with FLA, or a combination of both. Cases with prenatal abdominal ultrasonographic abnormalities after FLA should have close prenatal and postnatal assessment to detect bowel complications.

Influence of arsenic and boron on the water quality index in mining stressed catchments of Emet and Orhaneli streams (Turkey).

Emet and Orhaneli stream basins are characterized by intense mining of colemanite, the main borate mineral in the area. Unlike other global borate deposits, the colemanite of this region contains arsenic minerals (realgar and orpiment). Undoubtedly, improper management of mine wastes causes pollution of water resources, affecting human life and biota. In the present study, spatial and temporal variation in water quality of Emet and Orhaneli streams was assessed. The water quality index (WQI) model was used to rate the overall status of the water, and geographical information systems (GIS) was used to aid the visualization of results. No significant differences in WQIs for the three-monitoring periods (March, July and October 2017) were noted. The WQI in the region is highly influenced by arsenic (As) and boron (B), with a strong positive correlation (p < 0.05, r2 = 0.971). The As and B concentrations in Emet stream were 1.88-1907 µg/L and 0.01-1900 mg/L, respectively. Whereas for Orhaneli stream, respective As and B levels ranged from 5.17 to 116 µg/L and 0.01 to 5.45 mg/L. Globally, the As level in Emet stream basin is comparable to some of the words major contaminated regions such as Rapti River Basin (India) and Xieshui River (China). However, the uniqueness of this basin is seen in B and As trends, and input routes like active geothermal waters and weathering of the realgar (AsS) and orpiment (As2S3) from colemanite nodules. This paper demonstrates the influence of pollutants associated with basin geochemistry and exploration of mineral resources on WQI.

Batch fermentation of succinic acid from cheese whey by Actinobacillus succinogenes under variant medium composition.

Bio-based succinic acid production has attracted global attention since its consideration as a potential replacement to petroleum-based platform chemicals. This study used three different CO2 sources, namely NaHCO3, K2CO3 and MgCO3 for fermentation of succinic acid (SA) by Actinobacillus succinogenes under three distinct substrate conditions i.e. lactose, whey and whey devoid of any supplements. Batch experiments were performed in both anaerobic flasks and 5L benchtop fermenter. SA fermentation in anaerobic flasks was unfettered by supplementary nutrients. However, fermentation in the benchtop fermenter devoid of supplementary nutrients resulted into 42% reduction in SA yield as well as lower SA productivities. Furthermore, a significant reduction of cell growth occurred in anerobic flasks at pH < 6.0, and complete termination of bacterial activity was noted at pH < 5.3. The highest SA titer, yield and productivity of 15.67 g/L, 0.54 g/g and 0.33 g/L/h, respectively, was recorded from whey fermentation with MgCO3. The present study further highlights significant inhibitory effect of K2CO3 buffered medium on Actinobacillus succinogenes. Thus, we can claim that environmental pollution as well as costs of SA production from whey can be reduced by leveraging on whey residual nutrients to support the activity of Actinobacillus succinogenes.

Distal renal tubular acidosis and severe hypokalemia: a case report and review of the literature.

BACKGROUND: Distal renal tubular acidosis is a relatively infrequent condition with complex pathophysiology that can present with life-threatening electrolyte abnormalities. CASE PRESENTATION: We describe a case of a 57-year-old Caucasian woman with previous episodes of hypokalemia, severe muscle weakness, and fatigue. Upon further questioning, symptoms of dry eye and dry mouth became evident. Initial evaluation revealed hyperchloremic metabolic acidosis, severe hypokalemia, persistent alkaline urine, and a positive urinary anion gap, suggestive of distal renal tubular acidosis. Additional laboratory workup and renal biopsy led to the diagnosis of primary Sjögren's syndrome with associated acute tubulointerstitial nephritis. After potassium and bicarbonate supplementation, immunomodulatory therapy with hydroxychloroquine, azathioprine, and prednisone was started. Nonetheless, her renal function failed to improve and remained steady with an estimated glomerular filtration rate of 42 ml/min/1.73 m2. The literature on this topic was reviewed. CONCLUSIONS: Cases of renal tubular acidosis should be carefully evaluated to prevent adverse complications, uncover a potentially treatable condition, and prevent the progression to chronic kidney disease. Repeated episodes of unexplained hypokalemia could be an important clue for diagnosis.

Heavy metal pollution and spatial distribution in surface sediments of Mustafakemalpasa stream located in the world's largest borate basin (Turkey).

Mining activities in addition to the geology of Mustafakemalpasa catchment have for long been linked to its deteriorating water and sediment quality. This study assessed contamination levels of heavy metals and other major elements (Pb, As, B, Cd, Zn, Cr, Mo, Co, Ni, Cu, and Ag) in surface sediments of the area, and identified possible pollution sources. Sediment quality indicators, such as contamination factor (CF), enrichment factor (EF), geo-accumulation index (Igeo) and sediment quality guidelines were used, in addition to multivariate statistical technics; Pearson Correlation Matrix (PCM), Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). The highest contamination (annual average > 110 mg kg-1) was revealed by B, Cr, Ni, Zn and As. Moreover, As, Cd and Ni levels exceeded their respective probable effect concentrations (PEC), posing a potential negative impact to biota. The highest Igeo values were recorded for Cr, B, Ni, As and Zn, and occurred near urban settlements and mining sites, particularly of coal and chromium. The present study also suggests use of site rank index (SRI) as an alternative to pollution load index (PLI), since the former is derived from the data of interest and eliminates arbitrary classifications. The sources of heavy metals in the sediments were attributed to fly ashes of coal-powered plants, urban waste leachate and weathering of sulfide ore minerals for Pb, Zn and Cu; urban-industrial wastes and mining wastes for Ni. Although Cr, As, Cd and B were ascribed to natural occurrence, their presences in river sediment is accelerated by mining.

Positron emission tomography in recurrent hepatoblastoma.

Early detection of recurrent hepatoblastoma is not always possible with conventional imaging methods such as computed tomography (CT) and magnetic resonance imaging (MRI). This article describes three cases of recurrent hepatoblastoma in which positron emission tomography (PET) using F(18)-fluoro-deoxy-glucose (FDG-PET) was used to locate the site of recurrence. In the first two patients, FDG-PET accurately located recurrent disease where it was not detected by conventional imaging modalities, including CT and MRI. In the third patient, FDG-PET imaging also located the recurrent disease in an MRI-identified adrenal metastasis. The technique of "coregistration" using PET with CT and MRI scans was used in the cases described. This improves the anatomical localization of metabolically active sites and was particularly useful for determining the surgical approach. The difficulties of conventional imaging in locating early tumor recurrence or metastatic disease in hepatoblastoma make FDG-PET imaging an important investigation that may impact patient management.