الفهرس 
. Effect of carbon source on carotenoid production by Rhodotorula spOnly 14 pages are availabe for public view
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Abstract
Six of yeast isolates able to produce carotenoid were isolated from different plants. All the isolates are belonging to Rhodotorula spp. were identified by physiological and molecular genetic tools. Physiological identification were carried out by assimilation of carbon sources, assimilation of nitrogen sources and antibiotic resistance pattern using disk diffusion method. The fragment size polymorphism (FSP) were used for molecular genetic identification. The Internal Transcribed Spacer (ITS1) and (ITS2) regions of the isolates were amplified separately. The isolates were grouped based on fragment size polymorphism (FSP) of the ITS amplicon. For precise and final identification, the ITS-PCR products were subjected to sequencing followed by Blastn analysis. The obtained results revealed that two isolates were identified as Rhodotorula mucilaginosa, and the other four isolates were identified as R. glutinis.
The carotenoid production was studied in all Rhodotorula isolates after 3, 6 and 12 days, Isolation strain Rh.5 was the highest isolate for comparing with the carotenoid production other isolates.
The cell density was determined by several methods, wet weight, dry weight, optical density (O.D) and colony forming unit (CFU). All of methods after different incubation period were achieved the Rh.5 the best growth rate compare all isolates but the statics analysis were resulted no different significant between all isolates in growth rate.
Total lipid was measured for the six different Rhodotorula spp after two days, Rh.2 and Rh.3 give high level of lipid production. Correlation between β-carotene and lipid formation were evaluated. After 6 and 12 days. Total lipid production in all isolates were decreased after 12 days but disparity in β-carotene production after 6 and 12 days. Lipid production and β-carotene were correlated by used Person correlation. After 6 days, The correlation coefficient was 0.53 Average correlation non-significant. After 12 days, the correlation coefficient was 0.52 so average correlations non-significant also.
Genetic improvement for Rhodotorula glutinis ACGEBFAC Rh.5 was mutagenized to induce over production of carotenoid by Chemical mutagenesis EMS (Ethyl Methane Sulfonate). The results indicated that the mutagenesis can improve the productivity of β-carotene. The improved mutants could be selected from variants that induced by mutagenesis.