Stress tolerance and growth of trehaloseand mannitol deficient mutants inAspergillus niger

Abstract: There are several fungal species including Aspergillus niger that are responsible for foodspoilage. The conidia of Aspergillus niger contain mannitol and trehalose and thesecompounds act as stress protectants and keep the cells viable. In my experiments, Iobserved the survival after stress in trehalose and mannitol deficient mutants ofAspergillus niger and compared with wild type strains. I applied different treatments likeheat shock, freeze-drying and different energy sources on mutants and wild types sporesat different ages. The results indicate that 1-month-old spores of mutant of ΔtppB andΔmpdA are more vulnerable at high and low temperatures. These experiments indicatethat the trehalose deficient mutant ΔtppB and the mannitol deficient mutant ΔmpdA aremore sensitive compared to wild type and most probably due to their lower mannitol andtrehalose levels.