4939
DALIA MUSTAFA MOHAMMED ABD EL MOWLA
STUDIES ON PRODUCTION OF BIODIESEL FROM YEAST
Biodiesel, lipids-producing yeast, extraction lipid, fatty acid profile, 26S rRNA gene, cultural conditions
The present work aimed to study the yeast producing lipid and promising for biodiesel production. The objective of study included isolation yeast capable of producing lipid , screening for the most efficient isolates, estimation biomass, lipid weight and lipid content, determination of the optimum nutritional and environmental conditions for lipid production and analysis the fatty acid profiles and comparing to biodiesel oil Results could be summarized in the following points; A number of 76 yeast isolates were isolated from different sources included soil, organic manure, rotted fruits and different pickles based on the typical morphological character of yeast using light microscope. These isolates were screened on its ability to accumulate the intracellular lipid within the cells by culturing on nitrogen-limited medium (productive medium) and using Sudan Black B staining technique. A number of lipid producing yeast isolates (60) were detected. Estimation of biomass, lipid yield and lipid content were done for 33 oleaginous yeast isolates, based on amount of lipid accumulation. Four isolates (S5, D5, J3 and C9) proved to be the more promising isolates depending on the previous parameters of biomass, lipid yield and lipid content. The biologicalactivity of these isolates was studied in N-limited medium. The growth parameters such as lipid content, biomass yield, consumed sugar, sugar utilization efficiency, conversion coefficient, lipid productivity were determined during the fermentation time course. The lipid synthesis was partially associated with linear growth phase and during stationary phase. The fatty acids profile analysis was achieved that the lipid extracted from the four promising yeast isolates mainly contained the principal fatty acids (triacylglyceols, TAGs) as palmitic acid (C16:0),stearic acid (C18:0), oleic acid (C18:1) and linoleic acid (C18:2) which is similar to that of vegetable oils. The ratio of saturated and unsaturated fatty acids for the four oleaginous yeasts was also varied. The isolates S5 and D5 which showed the most potential ability in producing lipid and had the similar fatty acid profile of plant oils, were identified by a molecular genetics technique. They were identified as Candida tropicalis (S5) and Issatchenkia orientalis (D5). The highest biomass, lipid weight, lipid content, consumed sugar, sugar utilization efficiency, yield factor, conversion coefficient and lipid productivity were achieved by growing Candida tropicalis (S5) on Nlimited medium containing (80 g/l) glucose , mixture of yeast extract (1 g/l) and NH4(SO4)2 (1 g/l) with C/N ratio 115 with pH 6 and incubation under shaking condition at 30 ºC for 6 days, While Issatchenkia orientalis (D5) growing on N-limited medium containing (157.5 g/l) glucose, urea (1.36 g/l), C/N ratio was 100 with pH 5.5 and under shaking condition at 30 ºC for 4 days. So, it was suggested that the yeast strains Candida tropicalis (S5) and Issatchenkia orientalis (D5) could play a key role in the economic production of biodiesel.
2015
M.Sc
Ain Shams
Agriculture