Effect of Tempeature of Incubation on the Growth, Sporulation and Secondary Metabolites Production of Aspergillus umbrosus

Abstract

Temperature is one of the most important factors influencing growth, sporulation and survival of the microorganisms. On a certain optimum temperature microorganisms will grow normally and will produce antibiotic. In this study the cultures of A. umbrosus (Bainier & Sartory) were grown on the modified Richard’s medium and then incubated at different temperature, i.e.; 15, 20, 25, 26, 30, 35, 40, 45 and 50°C for 12 days at pH 5. In respect of the incubation temperature Aspergillus umbrosus has shown a very narrow range of tolerance. Below 20°C, growth rate was very less with minimum sporulation and light yellow colouration of the medium.  Optimum growth occurred at 30°C with equally good growth at 26°C. This gives a range of 26-30°C for its best growth. It tolerated temperature up to 35°C, beyond which it did not grow at all, there were no growth visualized at 40, 45 and 50°C Sporulation was also good at 26 and 30°C with dark-brown coloration of the medium, indicated the secretion of secondary metabolites. At 35°C the growth and sporulation were negatively affected and the medium colour was also greenish.