Fig. 3From: Ameliorating effects of chicken feathers in plant growth promotion activity by a keratinolytic strain of Bacillus subtilis PF1 A Visual observation of ammonia production by strain PF1 (a) and control (b) test. B Production of ammonia by Bacillus subtilis PF1 in the presence of different concentrations of feathers. The result is represented as mean ± standard deviation of three independent variablesBack to article page