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Spathaspora passalidarum is a natural xylose fermenting yeast that have the fungal pathway for converting xylose to ethanol. The second enzyme in this pathway is NAD +-dependent Xylitol dehydrogenase which converts xylitol to xylulose. In this study, the sequence of the nucleotides for XYL2 gene is found in JGI site. It consists of 1098 bp and code for 365 amino acids. The forward and reverse primers were designed with restriction sites on the 5` termini which are SacII and NotI restriction enzyme respectively using Lasergene 9.0 program. Genomic DNA was isolated and purified from S .passalidarum and amplified using PCR and it cloned into pSN303 resulting of the pYIM2 plasmid. Then it is transformed into Escherichia coli. This plasmid was isolated from E. coli and retransformed into S. cerevisiae and transformant is called YJTY2. Results showed that enzyme specific activities with NAD + as cofactors were 2.32 and 0.0 U/mg for S. cerevisiae YJTY2 and S. cerevisiae (CENPK2.1D) respectively. The enzyme did not show any activity with NADP + as a cofactor. This enzyme is NAD + dependent and can be used in combination with xylose reductase in S. cerevisiae to be able to ferment xylose.

The study was conducted to determine the impact of the magnetic field poles on aflatoxins produced by Aspergillus flavus. The subjected fungus to the northern pole, southern pole, both poles and their influences were compared with the control at which the fungus was not affected by magnetic field energy. Aspergillus flavus was influenced by magnetic field energy which applied through a magnet at different forces (5, 7,10,30,50 Gauss) for seven days at temperature of 27 o C. There are no different between the uses of magnate with 5 or 50 Gauss. The effect of magnetic field poles was observed on the growth of Aspergillus flavus on solid and liquid media. The southern pole had a positive effect on the growth of Aspergillus flavus by increasing the diameter of the colony or the turbidity of growth medium, while the northern pole had a negative influence on the growth of A. flavus, diameter or the turbidity, while the treatment of northern and southern poles together and the control treatment are equal. The most important conclusion that have been observed was the effect of magnetic field poles on the concentration of total aflatoxin produced by A. flavus, which was 454.73 ppb (when treated with southern pole) and 25.40 ppb (when treated with northern pole) while the control 212.46 ppb and both poles 88.33 ppb by using ELISA technique.

The effect of static magnetic field (MF) on the growth and biochemical indices of five fungal genera were studied. Exposing the above genera to the northern pole, southern pole and both poles and their influences were compared with the control treatment (without MF energy). The static MF of 10 gauss was applied to the above fungal genera for seven days at 28°C. The effect of static MF energy on the growth of fungal genera on solid media Sabouraud Dextrose Agar (SDA) and Potato Dextrose Agar (PDA) was classified as stimulatory, inhibitory and no observable effect on growth of fungal genera. The effects of MF poles (southern, northern and both) inhibited the growth of Fusarium oxysporum, while the MF poles stimulated the growth of fungal genera (Aspergillus niger, Alternaria alternate and Penicillium chrysogenium) and had no observable effect of southern pole and both poles on growth of Rhizopus oryzae, while the northern pole inhibited the growth of R. oryzae compared with control group by measuring the growth diameter (cm). The effects of MF poles on the biochemical indices of the fungal genera were performed by filtering the growth and measuring the enzyme activity in the filterate. Exposing the fungal genera to the northern pole, southern pole. The fungal genera were influenced by MF energy for 3 days at 28°C and pH6.5 showed increased in the activities of amylase and protease due to northern pole at significant difference (at the 0.05 levels), the northern pole increased amylase activity (U/ml) in the culture medium filteratedof P. chrysogenumup to (0.246 U/ml) higher than other mentioned genera, A. niger, F. oxysporum, R. oryzae and A. alternata 0.172, 0.146, 0.116, 0.105U/ml respectively. The northern pole increased protease activity (U/ml) in the culture filterate of P. chrysogenumup to (0.081 U/ml) higher than other mentioned genera, A. niger, A. alternata , R. oryzae and F. oxysporum 0.08, 0.074, 0.056,0.054U/ml respectively and decreased when treated with southern pole however it was higher than the control treatment under optimum condition.