It can be clearly distinguished that there were
four phases in the fermentation for all the samples: first exponential
growth phase, limiting-step phase, second exponential growth
phase and stationary phase. As can be seen in Fig. 2a, the concentration
of acetate in blank test T00 was at about 1500 mg/L at initial
30 h where the soluble and easily digestible portions of the untreated
maize straw were converted.