DefinePK

Abstract

Bacillus subtilis ATCC 11774 was exploited to produce amino acids on a medium containing olive cake as non-traditional carbon and nitrogen source. Initially, the potential proteolysis of B. subtilis ATCC 11774 was sequentially optimized for protease production based on statistical strategy. In which, the two level Plackett-Burman design revealed peptone and olive cake as the significant factors affecting protease production. Optimization of both constituents in addition to pH using central composite design maximized protease production (30.3 U mL-1 min-1) by an overall 4.59-fold increase as compared to the non-optimized (6.6 U mL-1 min-1) medium, with marked evidence for the biosynthesis of total free amino acids, being 3403 μg mL-1, accompanied with the reduction in final culture pH down to 4.3. The differentiation of the filtrate of optimized protease production medium using amino acid analyzer revealed glutamic acid (1185.9 μg mL-1) as the highest synthesized amino acid. Other minor amounts of amino acids were also detected. Interestingly, this is the first report on the production of amino acids from olive cake-based medium.