Temperature Study for Select Enzyme Production Using Aspergillus niger

Christopher S. Ray


The goal of this study was to determine a temperature at which to grow the fungus Aspergillus niger in order to optimize the enzyme activity of pectinase and α-galactosidase while also evaluating the cell doubling time of the fungus at the temperatures run. Overall, it was hypothesized that higher temperatures during growth would improve the fungal growth rate and speed up the enzyme production needed for the desired soy flour carbohydrate hydrolysis.

Three biologically and industrially appropriate temperatures were chosen (20°C, 25°C, and 30°C). The fungus was grown in a shake flask and since the project objective was to optimize cell growth and enzyme production on soybean hull, a separate sucrose system was included to monitor fungal growth without interference from the solid substrate. All systems were tested at the same shaking speed, after which pectinase, α-galactosidase, pH change, and intracellular protein was measured throughout the growth cycle. Flasks 1-3 contained soy bean hull and flasks 4-6 contained sucrose as a carbon source.

Overall, this work is significant because it was previously unclear how sensitive the growth and enzyme production rates were to temperature and it was found that both 25°C and 30°C had positive results. This broadly impacts the field of enzyme production and possible commercialization of such enzymes.