Production of ethanol from hemicellulose fraction of cocksfoot grass using pichia stipitis

Abstract Background In this study, cocksfoot grass (Dactylis glomerata), an abundant lignocellulosic biomass was pretreated using different operational parameters using wet explosion (WEx) pretreatment for accessing the bioethanol potential of the hemicellulose fraction. Utilization of the hemicellulose liquid hydrolysate to ethanol is essential for economically feasible cellulosic ethanol processes. Fermentation of the separated hemicellulose liquid hydrolysates obtained after the WEx pretreatment was done by Pichia stipitis CBS 6054 (Scheffersomyces stipitis). Results The fermentation of the WEx liquid hydrolysate from the pretreatment at higher severity (180°C, 15 min, 87 psi oxygen and 190°C, 15 min, 0.2% sulfuric acid) was fully inhibited probable by the presence of higher concentrations of inhibitory compounds such as furfural, HMF and acetic acid. The ethanol yield among other WEx conditions was in the range of 89 to 158 mL/kg DM, with the highest yield (92% of theoretical maximum value) found for the lower pretreatment severity at 160°C, 15 min, 87 psi oxygen. Conclusions Our findings from this present study demonstrated that the release of hemicellulose sugars in the liquid hydrolysate is maximal when a lower pretreatment severity is applied. This is evident as the highest ethanol yields were found under the pretreatment conditions at lower severity. </jats:sec

Predictors of outcome of chest tube drainage of nonpurulent exudative pleural effusions

Background Although chest tube drainage is the primary management method for many pleural effusions, it has a failure rate of 9.4–48%. In this study, we examined the factors that predict the outcome of management of nonpurulent exudative effusions. The aim of this study was to determine the predictors of outcomes of chest tube drainage of pleural effusions. Methodology Consecutive patients who had a chest tube drainage of nonpurulent exudative pleural effusions were followed up in a prospective observational cohort study until extubation and discharge. Data on the management of the patients were recorded, analysed and compared between groups of patients with good and poor outcomes. Results Of the 52 patients studied, 38 had good outcomes, while 14 had poor outcomes. The mean±sd age was 39.7±15.9 years. Multivariate analysis demonstrated that empyema thoracis complicating drainage was an independent predictor of a poor outcome, while the duration of drainage ≤14 days and duration of illness before presentation <30 days were predictive of a good outcome. Conclusion Our results show that the development of empyema thoracis during drainage, a long duration of drainage and a prolonged period of illness before presentation are predictive of the outcome of chest tube drainage