Abstract

This research focused on isolation and characterization of a new strain of Bacillussp. from alkaline soil, which was able to producing extracellular alkaline protease and amylase from date waste at pH ranging from 8 to 11 and temperatures of 20 to 50°C. Purification was conducted by fractionation, concentration, and cation exchange chromatography. The yield and fold of enzyme purification was 24% and 50 times, respectively. Molecular weight of purified enzyme was measured by SDS-PAGE as 24.7 kDa. Produced alkaline protease by Bacillus sp. 2 - 5 showed the most caseinolytic activity (without any gelatinolytic activity) at pH > 10. The highest protease activity was achieved in the following conditions: starch concentration (as carbon source) 0.5 g/L, yeast extract and casamino acid (as mixed nitrogen source) 0.5 and 0.3% (w/w), temperature of 45°C at pH 10.7 after 36 h. Based on the optimization studies of production and purification stages, specific and protease activity 143550 APU/mg and 57420 APU/mL were achieved.

Key words: Alkalophilic bacillus, alkaline protease, process variables, purification, Date waste.