Acid protease production by solid-state fermentation using Aspergillus oryzae MTCC 5341: optimization of process...

Area of Science:

• Biotechnology
• Enzyme Production
• Microbial Fermentation

Background:

• Aspergillus oryzae MTCC 5341 produces extracellular acid proteases on wheat bran.
• Solid-state fermentation (SSF) is a key method for enzyme production.
• Optimization of SSF is crucial for maximizing enzyme yields.

Purpose of the Study:

• To optimize the solid-state fermentation (SSF) of Aspergillus oryzae MTCC 5341 for enhanced acid protease production.
• To identify optimal operating conditions for maximizing acid protease yield.
• To develop a predictive model for acid protease production using response-surface methodology.

Main Methods:

• Solid-state fermentation (SSF) of Aspergillus oryzae on wheat bran.
• Optimization of fermentation parameters including pH, temperature, defatted soy flour addition, and fermentation time.
• Application of response-surface methodology (RSM) for modeling and optimization.

Main Results:

• Initial optimization identified conditions (pH 5, 30°C, 4% defatted soy flour, 120 h) yielding 8.64 x 10^5 U/g bran.
• RSM predicted optimal levels (pH 5.4, 31°C, 4.4% defatted soy flour, 123 h) for maximum activity of 8.93 x 10^5 U/g bran.
• Experimental verification achieved 8.47 x 10^5 U/g bran, 94.8% of the predicted value, representing a four-fold increase over previous reports.

Conclusions:

• Optimized SSF conditions significantly enhance acid protease production by Aspergillus oryzae.
• The developed predictive model accurately forecasts enzyme production levels.
• This research reports the highest acid protease activity achieved to date using this microbial strain and substrate.