Investigation the Effect of Exposure Aspergillus niger Isolate to the UV Radiation on Its Superphosphate Fertilizer Dissolving Efficiency in Calcareous Soil

A laboratory experiment was conducted to demonstrate the importance of improving the efficiency of six isolates of Aspergillus niger fungi. Four isolates were exposed to UV-rays radiation at a distance of 30 cm, a wavelength of 254–255 nm during M15, M30, and M45 minutes. Exposure periods, both of wild (no UV-rays exposure) and no A.niger (C) as controls, all six isolates were identified molecularly by polymerase chain reaction technique extracted DNA of A. niger was analyzed to ensure gene completion through multiple sequence alignment by bioinformatic programs to study the improvement of dissolving efficiency of mutant and wild A. niger. They were incubated after the addition of superphosphate fertilizer (47% P2O5) at 90 mg P kg–1 applied to soil with controls( no A. niger or no superphosphate) for I, II, III, and IV weeks of incubation periods at 28 ± 1 °C. In addition, the DNA extraction and purification by NanoDrop of Thermo Scientific-200 A280/A260 ratio was 2.01 and confirmed that the sequences of nitrogenous bases by the method of multiple sequence alignment (MSA) as compared to the reference sequence of A. niger recorded in the gene bank under the accession number LC632396. Results proved that the M30 minutes exposure UV-rays radiation period was the superior dose when mutant Aspergillus niger obtained the highest amount of dissolved phosphate, reducing soil-pH with maximum biomass of A. niger during the M30 isolate during the third week (III).