abstract
The surface characteristics of immobilized yeast before and after adding CO2-laser pretreated corn stover
(LPCS) substrates were investigated using bioethanol production. Response surface methodology (RSM),
based on the BoxeBehnken design (BBD) for experiments, was used to optimize the doping condition. An
optimum experimental condition was obtained at pH 4.5, 2.08% yeast concentration, and 0.20% LPCS
substrates. Under this condition, doping LPCS increased the yield of bioethanol from 53% to 84%, which
matched the predicted value. After doping LPCS, the results of inverted microscope (IM) and atomic force
microscopy (AFM) illustrated that the immobilized gel beads changed from rod-like in shape with a
smooth surface to a larger rod-like ultrastructure with a rougher surface. The yield was relatively stable
within 28 d, with a downward trend subsequently appearing.
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