Viscometric Studies on the Biodegradation of Some Vegetable Oils using Aspergillus Niger

The continual utilization of vegetable oils in homes, restaurants, hotels and cosmetic industries require their preservation against microorganisms. Aerobic biodegradation of four different seed oils were carried out using Aspergillus niger in order to determined their susceptibility to these common microbes in a temperate climate. The intrinsic viscosities of the inoculated oils, incubated at temperature of 35oC, were determined from the relative viscosities measured at intervals of seven days for six weeks. The viscosities of the un-inoculated oils were determined and used as control. A gradual increase in the viscosities with increase in the time of incubation was observed. This was ascribed to the possible growth of the microbes as they consume the smaller molecules formed during the break down of the oil. A remarkable change in the colour of the oils sample was noticed. This was then attributed to break down of compounds responsible for colours in these oils. The maximum viscosity values were obtained on the twenty eight day of incubation beyond which a decline was observed.  This was credited to the formation of secondary metabolites. The Fourier Transform- Infra Red spectrogram and the pH supported the secretion of enzymes and subsequent conversion of oil to secondary metabolites by the Aspergillus niger.  Absorption peaks at 2923.04-2930.09cm-1 and 3359.14-3429.69 cm-1 were due to hydroxyl and carboxyl groups in the biodegraded compounds. Edible oils with high free fatty acid value would therefore, biodegrade easily if contaminated by common fungi such as Aspergillusniger at temperature of 35oC.  The consumption of edible oil without frying commonly practiced in Nigeria may have been the source of diseases such as diarrhea, flu, vomiting, etc. It is recommended that edible Oils such as Palm, Ground nut, Cotton seed oil should be stored at temperature below 30oC and properly covered to prevent any contact with fungi. Keywords: Oil, Biodegradation, Aspergillus niger, Viscosit

Characteristics and outcomes of COVID-19 patients admitted to hospital with and without respiratory symptoms

Background: COVID-19 is primarily known as a respiratory illness; however, many patients present to hospital without respiratory symptoms. The association between non-respiratory presentations of COVID-19 and outcomes remains unclear. We investigated risk factors and clinical outcomes in patients with no respiratory symptoms (NRS) and respiratory symptoms (RS) at hospital admission. Methods: This study describes clinical features, physiological parameters, and outcomes of hospitalised COVID-19 patients, stratified by the presence or absence of respiratory symptoms at hospital admission. RS patients had one or more of: cough, shortness of breath, sore throat, runny nose or wheezing; while NRS patients did not. Results: Of 178,640 patients in the study, 86.4 % presented with RS, while 13.6 % had NRS. NRS patients were older (median age: NRS: 74 vs RS: 65) and less likely to be admitted to the ICU (NRS: 36.7 % vs RS: 37.5 %). NRS patients had a higher crude in-hospital case-fatality ratio (NRS 41.1 % vs. RS 32.0 %), but a lower risk of death after adjusting for confounders (HR 0.88 [0.83-0.93]). Conclusion: Approximately one in seven COVID-19 patients presented at hospital admission without respiratory symptoms. These patients were older, had lower ICU admission rates, and had a lower risk of in-hospital mortality after adjusting for confounders