Fig. 3From: Tofu processing wastewater as a low-cost substrate for high activity nattokinase production using Bacillus subtilisResponse surface curves showing the effects of each component in the medium on the production of nattokinase. The response curves show the interaction between different factors. a Interaction between TPW and glucose; b Interaction between MgSO4 and glucose; c Interaction between MgSO4 and TPW; d Interaction between CaCl2 and glucose; e Interaction between CaCl2 and TPW; f Interaction between MgSO4 and CaCl2Back to article page