استخلاص و تقدير صبغة البيتا كاروتين من بعض أنواع جنس الـ Rhodotorula المعزولة و دراسة إمكانية زيادة إنتاجها بالتطفير

Beta-carotene pigment was extracted from 6 strains collected from different sources related to some species of the genus Rhodotorula sp. The maximum productivity was in the strain Rhodotorula mucilaginosa BA61 with amount 10.25 gm/l. The minimum productivity was from the strain R. minuta BA78 with amount 5.39 gm/l. The effects of the chemical mutagen ( MNNG ) and the physical mutagen ( UVC ) on the viability of the strains was studied. The results revealed that the chemical mutagen ( MNNG ) with the concentration 0.2 mg/ml has the clear effect on the viability of the strains, which killing percentage reached to 65.91% in the strain R. minuta BA78. Results of the study of mutagenesis with UVC showed that increase in killing percentage for all the studied strains with the increase of radiation period. The maximum effect was with the strain R. minuta BA78, the killing percentage reach to 100% with the radiation period 20 minute. The companying effects of chemical with the concentration 0.2 mg / ml and physical mutagen was studied. The result showed increase in killing percentage for the studied strains which reach to 100% with the radiation period 15 and 20 minute for the strain R. minuta BA78. The maximum effect on Beta-carotene production was on the strain R. mucilaginosa BA61, the productivity reach to maximum with amount 11. 45gm / l.