OBJECTIVE: The main objective of this study was to explore oleaginous yeast, Yarrowia lipolytica isolated from soil and optimization of culture conditions and medium components to obtained better quality microbial oil for biodiesel production.
METHODS: Fifty yeast strains were isolated from soil from different regions of Lahore and eleven of them were selected for oil production. The isolated yeast colonies were screened to further check their lipid producing capabilities by the qualitative analysis. Five yeast strains were designated as oleaginous because they produced more than 16% of oil based on their biomass. To estimate the total lipid content of yeast cells, the extraction of lipids was done by performing the procedure proposed by Bligh and Dyer. The transesterification of yeast oils was performed by using different methods. There were three different strategies customized to transesterifying microbial oil using base catalyzed transesterification, acid catalyzed transesterification and enzyme-based transesterification. After completion of transesterification, sample was used for fatty acid methyl esters (FAMEs) were analyzed by gas-chromatograph with ionization detector type MS.
RESULTS: The isolate IIB-10 identified as Yarrowia lipolytica produced maximum amount of lipids i.e. 22.8%. More amount of biomass was obtained when cane molasses was utilized as carbon source where it produced 29.4 g/L of biomass while sucrose and lactose were not utilized by IIB-10 and no biomass was obtained. Similarly, meat extracts showed best results when it was used as nitrogen source because it resulted in 35.8 g/L biomass of Yarrowia lipolytica IIB-10. The culturing conditions like size of inoculum, effect of pH and time of incubation were also studied. The 10% of inoculum size produced 25.4 g/L biomass at 120 h incubation time, while the pH 7 was the optimum pH at which 24.8 g/L biomass was produced by Yarrowia lipolytica IIB-10. GC-MS analysis showed that biodiesel produced by transesterification contained similar fatty acids as found in vegetable oil for this reason it is widely accepted feedstock for biodiesel production.
CONCLUSION: The analysis of fatty acids methyl esters showed the similar composition of microbial oil as in vegetable oils and high amount of methyl esters were obtained after transesterification. Therefore, potentially oleaginous yeast could be used to generate a large amount of lipids for biodiesel production that will be the better substitute of petroleum-based diesel and will also control the environmental pollution.
METHODS: Data from the first wave Malaysian Elders Longitudinal Research (MELoR) study comprising urban dwellers aged 55 years and above were utilized. Twelve-month fall histories were established during home-based, computer-assisted interviews which physical performance, anthropometric and laboratory measures were obtained during a hospital-based health check. Gait speed, exhaustion, weakness, and weight loss were employed as frailty markers.
RESULTS: Data were available for 1415 participants, mean age of 68.56 ± 7.26 years, 57.2% women. Falls and metabolic syndrome were present in 22.8% and 44.2%, respectively. After adjusting for age, sex, and multiple comorbidities, metabolic syndrome was significantly associated with falls in the sample population [odds ratio (OR): 1.33, 95% confidence interval (CI): 1.03; 1.72]. This relationship was attenuated by the presence of slow gait speed, but not exhaustion, weakness, or weight loss.
CONCLUSION: Metabolic syndrome was independently associated with falls among older adults, and this relationship was accounted for by the presence of slow gait speed. Future studies should determine the value of screening for frailty and falls with gait speed in older adults with metabolic syndrome as a potential fall prevention measure.