Fig. 3
![Fig. 3](http://media.springernature.com/full/springer-static/image/art%3A10.1186%2Fs13068-017-0932-8/MediaObjects/13068_2017_932_Fig3_HTML.gif)
Response surface plots of Box–Behnken design for optimization of the β-glucosidase enzyme production by B. subtilis RA10. Figure shows the interaction between a beef extract and Paddy straw, b NaNO3 and beef extract, c PEG 6000 and paddy straw, d NaNO3 and PEG 6000