Optimization of medium composition for erythritol production from glycerol by Yarrowia lipolytica using response surface methodology.

Several factors affecting erythritol production from glycerol by Yarrowia lipolytica Wratislavia K1 strain were examined in batch fermentations. Ammonium sulfate, monopotassium phosphate, and sodium chloride were identified as critical medium components that determine the ratio of polyols produced. The central composite rotatable experimental design was used to optimize medium composition for erythritol production. The concentrations of ammonium sulfate, monopotassium phosphate, and sodium chloride in the optimized medium were 2.25, 0.22, and 26.4 g L(-1), respectively. The C:N ratio was found as 81:1. In the optimized medium with 100 g L(-1) of glycerol the Wratislavia K1 strain produced 46.9 g L(-1) of erythritol, which corresponded to a 0.47 g g(-1) yield and a productivity of 0.85 g L(-1) hr(-1). In the fed-batch mode and medium with the total concentration of glycerol at 300 g L(-1) and C:N ratio at 81:1, 132 g L(-1) of erythritol was produced with 0.44 g g(-1) yield and a productivity of 1.01 g L(-1) hr(-1.)

Cardiogenic pulmonary oedema: alarmingly poor long term prognosis. Analysis of risk factors.

BACKGROUND: Acute heart failure (AHF) is a life-threatening condition associated with poor prognosis. AIM: To investigate the long term prognosis and identify prognostic factors among patients who were discharged after an episode of cardiogenic pulmonary oedema. METHODS: We enrolled 84 patients (M: 56%, n = 47) who were discharged with cardiogenic pulmonary oedema as a diagnosis. Clinical, biochemical and echocardiographic variables were collected and analysed. The completeness of two- and five-year follow-up was 100% and 96%, respectively. RESULTS: The median (IQR) age was 74 years (64-81), left ventricular ejection fraction was 35% (27-45), blood pressure on admission was 140/90 mm Hg (115-180/70-100), estimated glomerular filtration rate was 60 mL/min/1.73 m2 (45-73). Forty per cent (n = 34) of the patients had a history of atrial fibrillation (AF), however, AF was directly involved with pulmonary oedema only in 4% (n = 3) of the cases. Acute myocardial infarction (AMI) accounted for 34% (n = 29) of all the causes of pulmonary oedema and was associated with a better two-year prognosis compared to other causes of pulmonary oedema (p = 0.018). Two- and five-year mortality was 45% (n = 38) and 72% (n = 58), respectively. Co-morbidities were common. Ischaemic heart disease and arterial hypertension were present in 83% and 70% of the patients, respectively. Multivariable analysis identified increased left ventricular mass (RR 3.609, 95% CI 1.235-10.547, p = 0.017) and treatment with long-acting vasodilator drugs (LAVDs) (RR 4.881, 95% CI 1.618-14.727, p = 0.004) as independent negative prognostic factors, whereas in-hospital therapy with beta-blockers created a distinctly protective effect (RR 0.123, 95% CI 0.033-0.457, p = 0.002) in the two-year follow-up. Five-year mortality was independently associated with older age (RR 1.08, 95% CI 1.02-1.14, p = 0.005) and treatment with LAVDs (RR 6.4, 95% CI 1.47-28.14, p = 0.012), while percutaneous coronary intervention (RR 0.17, 95% CI 0.05-0.58, p = 0.004) significantly decreased the risk. CONCLUSIONS: AHF is a heterogeneous syndrome with a very high remote mortality. LAVDs administered during the hospital stay as well as older age on admission correlate with higher long-term overall mortality. In the age of percutaneous coronary intervention, AMI aetiology of pulmonary oedema is no longer a negative prognostic factor for the long-term prognosis.

Valorization of raw glycerol for citric acid production by Yarrowia lipolytica yeast

In the present report, citric acid production from raw glycerol in two fed-batch systems by acetate negative-mutants of Yarrowia lipolytica: Wratislavia 1.31 and Wratislavia AWG7 was compared. In the system, in which the total glycerol concentration was 200 g∙L-1, the substrate was added by pulsed additions, and in the other, in which the total glycerol concentration was 300 g∙L-1, the substrate was added at a constant feeding rate of 1.4 g∙h-1. Despite high citric acid concentrations (155.2 and 157.5 g∙L-1 with Y. lipolytica Wratislavia 1.31 and Y. lipolytica Wratislavia AWG7, respectively) obtained from 300 g∙L-1 of glycerol, the yield of citric acid was similar, i.e. about 0.6 g∙g-1. The volumetric citric acid productivity was markedly higher (1.05 and 0.94 g∙L-1h-1 with Y. lipolytica Wratislavia 1.31 and Y. lipolytica Wratislavia AWG7 strains, respectively) in the cultures containing 200 g∙L-1 of carbon source.

High-yield production of erythritol from raw glycerol in fed-batch cultures of Yarrowia lipolytica.

An acetate-negative mutant of Yarrowia lipolytica Wratislavia K1 was selected that, when grown with 300 g raw glycerol l(-1) at pH 3, produced 170 g erythritol l(-1) after 7 days, corresponding to a 56% yield and a productivity of 1 g l(-1) h(-1). The Wratislavia K1 strain did not produce citric acid.