[Fermentation conditions for production of alkaline elastase by alkaliphilic Bacillus XE22-4-1].

A extracellular alkaline elastase producing bacterial strain Bacillus XE22-4-1, with the optimum pH of 10.0 for its growth, was isolated and screened from alkali lake of Tibet. 2% glucose and 0.25% yeast extract are respectively the appropriate carbon and nitrogen source on elastase production. Soymeal can promote elastase production. The fermentation conditions in a 2 L stirred tank were investigated. The results have revealed that the dissolved oxygen is the most effective factor on elastase production. The maximum elastolytic activity reached 266 u/mL among 48 hours of fermentation by combination of enhancing aeration and changing the mixing speed.