The effect of salinity and osmotic pressure of the medium on the growth, sporulation and changes in the total organic acid content of Aspergillus flavus and Penicillium chrysogenum.

Extreme conditions of a medium effects the growth of microorganisms. The effect of salinity (NaCl) and osmotic pressure on the vegetative and reproductive growth as well as on changes in the amount of total organic acid of Aspergillus flavus and Penicillium chrysogenum; isolated from the soil; have been studied in this investigation. The vegetative growth of both species increased with an increase in the NaCl content of the nutrient medium. The maximum increase was observed in A. flavus in the nutrient medium containing 9% NaCl, as compared to the control. On the other hand the salinity and the osmotic pressure values, depending on the changes in the salinity; had inhibitive effects on the production of conidia of A. flavus and stimulative effects on those of Penicillium chrysogenum. P. chrysogenum for maximum production of conidia was observed in the nutrient medium containing 1% NaCl whereas maximum vegetative growth was recorded in the nutrient medium containing 9% NaCl. However, no definite results were obtained concerning a parallelity between the increase in vegetative and reproductive growth. In view of these observations, for a production of total organic acid incubation medium of the fungal species, each species must reach a particular conidia production, and salinity and osmotic pressure of the medium effects their production differently depending on the species.

The effect of osmotic pressure and salinity of the medium on the growth and sporulation of Aspergillus niger and Paecilomyces lilacinum species.

The effect of osmotic pressure and salinity on the production of conidia and growth of Aspergillus niger and Paecilomyces lilacinum, isolated from the soil, have been studied in this investigation. The maximum production of conidia in both species was observed in the nutrient medium containing 1% NaCl wheras maximum growth was recorded in the nutrient medium containing 3% NaCl. It has been thus observed that the salinity and the osmotic pressure related to it effect the reproductive as well as the vegetative development of both species, and these effects have been observed to be different. The sensitivity of both fungal species to the salt was also investigated. Conidia were not observed in the P. lilacinum species grown in nutrient medium with 5% NaCl whereas conidial development did take place in the case of Aspergillus niger grown in the nutrient medium containing 5% NaCl.